Unify all uses of 'gcx and 'tcx.

src/librustc/cfg/construct.rs

@@ -8,7 +8,7 @@ use crate::hir::{self, PatKind};
 use crate::hir::def_id::DefId;
 
 struct CFGBuilder<'a, 'tcx: 'a> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     owner_def_id: DefId,
     tables: &'a ty::TypeckTables<'tcx>,
     graph: CFGGraph,
@@ -30,7 +30,7 @@ struct LoopScope {
     break_index: CFGIndex,    // where to go on a `break`
 }
 
-pub fn construct<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, body: &hir::Body) -> CFG {
+pub fn construct<'tcx>(tcx: TyCtxt<'tcx>, body: &hir::Body) -> CFG {
     let mut graph = graph::Graph::new();
     let entry = graph.add_node(CFGNodeData::Entry);
 

src/librustc/cfg/graphviz.rs

@@ -12,7 +12,7 @@ pub type Node<'a> = (cfg::CFGIndex, &'a cfg::CFGNode);
 pub type Edge<'a> = &'a cfg::CFGEdge;
 
 pub struct LabelledCFG<'a, 'tcx: 'a> {
-    pub tcx: TyCtxt<'tcx, 'tcx>,
+    pub tcx: TyCtxt<'tcx>,
     pub cfg: &'a cfg::CFG,
     pub name: String,
     /// `labelled_edges` controls whether we emit labels on the edges

src/librustc/cfg/mod.rs

@@ -49,7 +49,7 @@ pub type CFGNode = graph::Node<CFGNodeData>;
 pub type CFGEdge = graph::Edge<CFGEdgeData>;
 
 impl CFG {
-    pub fn new<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, body: &hir::Body) -> CFG {
+    pub fn new<'tcx>(tcx: TyCtxt<'tcx>, body: &hir::Body) -> CFG {
         construct::construct(tcx, body)
     }
 

src/librustc/dep_graph/dep_node.rs

@@ -204,10 +204,10 @@ macro_rules! define_dep_nodes {
         impl DepNode {
             #[allow(unreachable_code, non_snake_case)]
             #[inline(always)]
-            pub fn new<'a, 'gcx, 'tcx>(tcx: TyCtxt<'gcx, 'tcx>,
-                                       dep: DepConstructor<'gcx>)
+            pub fn new<'a, 'tcx>(tcx: TyCtxt<'tcx>,
+                                       dep: DepConstructor<'tcx>)
                                        -> DepNode
-                where 'gcx: 'a + 'tcx,
+                where 'tcx: 'a,
                       'tcx: 'a
             {
                 match dep {
@@ -307,7 +307,7 @@ macro_rules! define_dep_nodes {
             /// refers to something from the previous compilation session that
             /// has been removed.
             #[inline]
-            pub fn extract_def_id(&self, tcx: TyCtxt<'_, '_>) -> Option<DefId> {
+            pub fn extract_def_id(&self, tcx: TyCtxt<'_>) -> Option<DefId> {
                 if self.kind.can_reconstruct_query_key() {
                     let def_path_hash = DefPathHash(self.hash);
                     tcx.def_path_hash_to_def_id.as_ref()?
@@ -400,7 +400,7 @@ impl DefPathHash {
 
 impl DefId {
     #[inline(always)]
-    pub fn to_dep_node(self, tcx: TyCtxt<'_, '_>, kind: DepKind) -> DepNode {
+    pub fn to_dep_node(self, tcx: TyCtxt<'_>, kind: DepKind) -> DepNode {
         DepNode::from_def_path_hash(kind, tcx.def_path_hash(self))
     }
 }
@@ -442,50 +442,50 @@ rustc_dep_node_append!([define_dep_nodes!][ <'tcx>
 ]);
 
 pub trait RecoverKey<'tcx>: Sized {
-    fn recover(tcx: TyCtxt<'tcx, 'tcx>, dep_node: &DepNode) -> Option<Self>;
+    fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self>;
 }
 
 impl RecoverKey<'tcx> for CrateNum {
-    fn recover(tcx: TyCtxt<'tcx, 'tcx>, dep_node: &DepNode) -> Option<Self> {
+    fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self> {
         dep_node.extract_def_id(tcx).map(|id| id.krate)
     }
 }
 
 impl RecoverKey<'tcx> for DefId {
-    fn recover(tcx: TyCtxt<'tcx, 'tcx>, dep_node: &DepNode) -> Option<Self> {
+    fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self> {
         dep_node.extract_def_id(tcx)
     }
 }
 
 impl RecoverKey<'tcx> for DefIndex {
-    fn recover(tcx: TyCtxt<'tcx, 'tcx>, dep_node: &DepNode) -> Option<Self> {
+    fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self> {
         dep_node.extract_def_id(tcx).map(|id| id.index)
     }
 }
 
-trait DepNodeParams<'gcx: 'tcx, 'tcx>: fmt::Debug {
+trait DepNodeParams<'tcx>: fmt::Debug {
     const CAN_RECONSTRUCT_QUERY_KEY: bool;
 
     /// This method turns the parameters of a DepNodeConstructor into an opaque
     /// Fingerprint to be used in DepNode.
     /// Not all DepNodeParams support being turned into a Fingerprint (they
     /// don't need to if the corresponding DepNode is anonymous).
-    fn to_fingerprint(&self, _: TyCtxt<'gcx, 'tcx>) -> Fingerprint {
+    fn to_fingerprint(&self, _: TyCtxt<'tcx>) -> Fingerprint {
         panic!("Not implemented. Accidentally called on anonymous node?")
     }
 
-    fn to_debug_str(&self, _: TyCtxt<'gcx, 'tcx>) -> String {
+    fn to_debug_str(&self, _: TyCtxt<'tcx>) -> String {
         format!("{:?}", self)
     }
 }
 
-impl<'gcx: 'tcx, 'tcx, T> DepNodeParams<'gcx, 'tcx> for T
+impl<'tcx, T> DepNodeParams<'tcx> for T
 where
     T: HashStable<StableHashingContext<'tcx>> + fmt::Debug,
 {
     default const CAN_RECONSTRUCT_QUERY_KEY: bool = false;
 
-    default fn to_fingerprint(&self, tcx: TyCtxt<'gcx, 'tcx>) -> Fingerprint {
+    default fn to_fingerprint(&self, tcx: TyCtxt<'tcx>) -> Fingerprint {
         let mut hcx = tcx.create_stable_hashing_context();
         let mut hasher = StableHasher::new();
 
@@ -494,39 +494,39 @@ where
         hasher.finish()
     }
 
-    default fn to_debug_str(&self, _: TyCtxt<'gcx, 'tcx>) -> String {
+    default fn to_debug_str(&self, _: TyCtxt<'tcx>) -> String {
         format!("{:?}", *self)
     }
 }
 
-impl<'gcx: 'tcx, 'tcx> DepNodeParams<'gcx, 'tcx> for DefId {
+impl<'tcx> DepNodeParams<'tcx> for DefId {
     const CAN_RECONSTRUCT_QUERY_KEY: bool = true;
 
-    fn to_fingerprint(&self, tcx: TyCtxt<'_, '_>) -> Fingerprint {
+    fn to_fingerprint(&self, tcx: TyCtxt<'_>) -> Fingerprint {
         tcx.def_path_hash(*self).0
     }
 
-    fn to_debug_str(&self, tcx: TyCtxt<'gcx, 'tcx>) -> String {
+    fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String {
         tcx.def_path_str(*self)
     }
 }
 
-impl<'gcx: 'tcx, 'tcx> DepNodeParams<'gcx, 'tcx> for DefIndex {
+impl<'tcx> DepNodeParams<'tcx> for DefIndex {
     const CAN_RECONSTRUCT_QUERY_KEY: bool = true;
 
-    fn to_fingerprint(&self, tcx: TyCtxt<'_, '_>) -> Fingerprint {
+    fn to_fingerprint(&self, tcx: TyCtxt<'_>) -> Fingerprint {
         tcx.hir().definitions().def_path_hash(*self).0
     }
 
-    fn to_debug_str(&self, tcx: TyCtxt<'gcx, 'tcx>) -> String {
+    fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String {
         tcx.def_path_str(DefId::local(*self))
     }
 }
 
-impl<'gcx: 'tcx, 'tcx> DepNodeParams<'gcx, 'tcx> for CrateNum {
+impl<'tcx> DepNodeParams<'tcx> for CrateNum {
     const CAN_RECONSTRUCT_QUERY_KEY: bool = true;
 
-    fn to_fingerprint(&self, tcx: TyCtxt<'_, '_>) -> Fingerprint {
+    fn to_fingerprint(&self, tcx: TyCtxt<'_>) -> Fingerprint {
         let def_id = DefId {
             krate: *self,
             index: CRATE_DEF_INDEX,
@@ -534,18 +534,18 @@ impl<'gcx: 'tcx, 'tcx> DepNodeParams<'gcx, 'tcx> for CrateNum {
         tcx.def_path_hash(def_id).0
     }
 
-    fn to_debug_str(&self, tcx: TyCtxt<'gcx, 'tcx>) -> String {
+    fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String {
         tcx.crate_name(*self).as_str().to_string()
     }
 }
 
-impl<'gcx: 'tcx, 'tcx> DepNodeParams<'gcx, 'tcx> for (DefId, DefId) {
+impl<'tcx> DepNodeParams<'tcx> for (DefId, DefId) {
     const CAN_RECONSTRUCT_QUERY_KEY: bool = false;
 
     // We actually would not need to specialize the implementation of this
     // method but it's faster to combine the hashes than to instantiate a full
     // hashing context and stable-hashing state.
-    fn to_fingerprint(&self, tcx: TyCtxt<'_, '_>) -> Fingerprint {
+    fn to_fingerprint(&self, tcx: TyCtxt<'_>) -> Fingerprint {
         let (def_id_0, def_id_1) = *self;
 
         let def_path_hash_0 = tcx.def_path_hash(def_id_0);
@@ -554,7 +554,7 @@ impl<'gcx: 'tcx, 'tcx> DepNodeParams<'gcx, 'tcx> for (DefId, DefId) {
         def_path_hash_0.0.combine(def_path_hash_1.0)
     }
 
-    fn to_debug_str(&self, tcx: TyCtxt<'gcx, 'tcx>) -> String {
+    fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String {
         let (def_id_0, def_id_1) = *self;
 
         format!("({}, {})",
@@ -563,13 +563,13 @@ impl<'gcx: 'tcx, 'tcx> DepNodeParams<'gcx, 'tcx> for (DefId, DefId) {
     }
 }
 
-impl<'gcx: 'tcx, 'tcx> DepNodeParams<'gcx, 'tcx> for HirId {
+impl<'tcx> DepNodeParams<'tcx> for HirId {
     const CAN_RECONSTRUCT_QUERY_KEY: bool = false;
 
     // We actually would not need to specialize the implementation of this
     // method but it's faster to combine the hashes than to instantiate a full
     // hashing context and stable-hashing state.
-    fn to_fingerprint(&self, tcx: TyCtxt<'_, '_>) -> Fingerprint {
+    fn to_fingerprint(&self, tcx: TyCtxt<'_>) -> Fingerprint {
         let HirId {
             owner,
             local_id,

src/librustc/dep_graph/graph.rs

@@ -557,7 +557,7 @@ impl DepGraph {
     /// a node index can be found for that node.
     pub fn try_mark_green_and_read(
         &self,
-        tcx: TyCtxt<'_, '_>,
+        tcx: TyCtxt<'_>,
         dep_node: &DepNode,
     ) -> Option<(SerializedDepNodeIndex, DepNodeIndex)> {
         self.try_mark_green(tcx, dep_node).map(|(prev_index, dep_node_index)| {
@@ -569,7 +569,7 @@ impl DepGraph {
 
     pub fn try_mark_green(
         &self,
-        tcx: TyCtxt<'_, '_>,
+        tcx: TyCtxt<'_>,
         dep_node: &DepNode,
     ) -> Option<(SerializedDepNodeIndex, DepNodeIndex)> {
         debug_assert!(!dep_node.kind.is_eval_always());
@@ -603,7 +603,7 @@ impl DepGraph {
     /// Try to mark a dep-node which existed in the previous compilation session as green.
     fn try_mark_previous_green<'tcx>(
         &self,
-        tcx: TyCtxt<'tcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         data: &DepGraphData,
         prev_dep_node_index: SerializedDepNodeIndex,
         dep_node: &DepNode,
@@ -790,7 +790,7 @@ impl DepGraph {
     #[inline(never)]
     fn emit_diagnostics<'tcx>(
         &self,
-        tcx: TyCtxt<'tcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         data: &DepGraphData,
         dep_node_index: DepNodeIndex,
         did_allocation: bool,
@@ -841,7 +841,7 @@ impl DepGraph {
     //
     // This method will only load queries that will end up in the disk cache.
     // Other queries will not be executed.
-    pub fn exec_cache_promotions<'tcx>(&self, tcx: TyCtxt<'tcx, 'tcx>) {
+    pub fn exec_cache_promotions<'tcx>(&self, tcx: TyCtxt<'tcx>) {
         let green_nodes: Vec<DepNode> = {
             let data = self.data.as_ref().unwrap();
             data.colors.values.indices().filter_map(|prev_index| {

src/librustc/dep_graph/safe.rs

@@ -33,7 +33,7 @@ impl DepGraphSafe for DefId {
 
 /// The type context itself can be used to access all kinds of tracked
 /// state, but those accesses should always generate read events.
-impl<'gcx, 'tcx> DepGraphSafe for TyCtxt<'gcx, 'tcx> {}
+impl<'tcx> DepGraphSafe for TyCtxt<'tcx> {}
 
 /// Tuples make it easy to build up state.
 impl<A, B> DepGraphSafe for (A, B)

src/librustc/hir/check_attr.rs

@@ -88,7 +88,7 @@ impl Target {
 }
 
 struct CheckAttrVisitor<'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
 }
 
 impl CheckAttrVisitor<'tcx> {
@@ -347,7 +347,7 @@ fn is_c_like_enum(item: &hir::Item) -> bool {
     }
 }
 
-fn check_mod_attrs<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, module_def_id: DefId) {
+fn check_mod_attrs<'tcx>(tcx: TyCtxt<'tcx>, module_def_id: DefId) {
     tcx.hir().visit_item_likes_in_module(
         module_def_id,
         &mut CheckAttrVisitor { tcx }.as_deep_visitor()

src/librustc/hir/def_id.rs

@@ -177,7 +177,7 @@ impl DefId {
         LocalDefId::from_def_id(self)
     }
 
-    pub fn describe_as_module(&self, tcx: TyCtxt<'_, '_>) -> String {
+    pub fn describe_as_module(&self, tcx: TyCtxt<'_>) -> String {
         if self.is_local() && self.index == CRATE_DEF_INDEX {
             format!("top-level module")
         } else {

src/librustc/hir/lowering.rs

@@ -413,8 +413,8 @@ impl<'a> LoweringContext<'a> {
         /// needed from arbitrary locations in the crate,
         /// e.g., the number of lifetime generic parameters
         /// declared for every type and trait definition.
-        struct MiscCollector<'lcx, 'interner: 'lcx> {
-            lctx: &'lcx mut LoweringContext<'interner>,
+        struct MiscCollector<'tcx, 'interner: 'tcx> {
+            lctx: &'tcx mut LoweringContext<'interner>,
             hir_id_owner: Option<NodeId>,
         }
 
@@ -458,8 +458,8 @@ impl<'a> LoweringContext<'a> {
             }
         }
 
-        impl<'lcx, 'interner> Visitor<'lcx> for MiscCollector<'lcx, 'interner> {
-            fn visit_pat(&mut self, p: &'lcx Pat) {
+        impl<'tcx, 'interner> Visitor<'tcx> for MiscCollector<'tcx, 'interner> {
+            fn visit_pat(&mut self, p: &'tcx Pat) {
                 match p.node {
                     // Doesn't generate a HIR node
                     PatKind::Paren(..) => {},
@@ -473,7 +473,7 @@ impl<'a> LoweringContext<'a> {
                 visit::walk_pat(self, p)
             }
 
-            fn visit_item(&mut self, item: &'lcx Item) {
+            fn visit_item(&mut self, item: &'tcx Item) {
                 let hir_id = self.lctx.allocate_hir_id_counter(item.id);
 
                 match item.node {
@@ -505,7 +505,7 @@ impl<'a> LoweringContext<'a> {
                 });
             }
 
-            fn visit_trait_item(&mut self, item: &'lcx TraitItem) {
+            fn visit_trait_item(&mut self, item: &'tcx TraitItem) {
                 self.lctx.allocate_hir_id_counter(item.id);
 
                 match item.node {
@@ -521,21 +521,21 @@ impl<'a> LoweringContext<'a> {
                 }
             }
 
-            fn visit_impl_item(&mut self, item: &'lcx ImplItem) {
+            fn visit_impl_item(&mut self, item: &'tcx ImplItem) {
                 self.lctx.allocate_hir_id_counter(item.id);
                 self.with_hir_id_owner(Some(item.id), |this| {
                     visit::walk_impl_item(this, item);
                 });
             }
 
-            fn visit_foreign_item(&mut self, i: &'lcx ForeignItem) {
+            fn visit_foreign_item(&mut self, i: &'tcx ForeignItem) {
                 // Ignore patterns in foreign items
                 self.with_hir_id_owner(None, |this| {
                     visit::walk_foreign_item(this, i)
                 });
             }
 
-            fn visit_ty(&mut self, t: &'lcx Ty) {
+            fn visit_ty(&mut self, t: &'tcx Ty) {
                 match t.node {
                     // Mirrors the case in visit::walk_ty
                     TyKind::BareFn(ref f) => {
@@ -559,11 +559,11 @@ impl<'a> LoweringContext<'a> {
             }
         }
 
-        struct ItemLowerer<'lcx, 'interner: 'lcx> {
-            lctx: &'lcx mut LoweringContext<'interner>,
+        struct ItemLowerer<'tcx, 'interner: 'tcx> {
+            lctx: &'tcx mut LoweringContext<'interner>,
         }
 
-        impl<'lcx, 'interner> ItemLowerer<'lcx, 'interner> {
+        impl<'tcx, 'interner> ItemLowerer<'tcx, 'interner> {
             fn with_trait_impl_ref<F>(&mut self, trait_impl_ref: &Option<TraitRef>, f: F)
             where
                 F: FnOnce(&mut Self),
@@ -579,8 +579,8 @@ impl<'a> LoweringContext<'a> {
             }
         }
 
-        impl<'lcx, 'interner> Visitor<'lcx> for ItemLowerer<'lcx, 'interner> {
-            fn visit_mod(&mut self, m: &'lcx Mod, _s: Span, _attrs: &[Attribute], n: NodeId) {
+        impl<'tcx, 'interner> Visitor<'tcx> for ItemLowerer<'tcx, 'interner> {
+            fn visit_mod(&mut self, m: &'tcx Mod, _s: Span, _attrs: &[Attribute], n: NodeId) {
                 self.lctx.modules.insert(n, hir::ModuleItems {
                     items: BTreeSet::new(),
                     trait_items: BTreeSet::new(),
@@ -593,7 +593,7 @@ impl<'a> LoweringContext<'a> {
                 self.lctx.current_module = old;
             }
 
-            fn visit_item(&mut self, item: &'lcx Item) {
+            fn visit_item(&mut self, item: &'tcx Item) {
                 let mut item_hir_id = None;
                 self.lctx.with_hir_id_owner(item.id, |lctx| {
                     if let Some(hir_item) = lctx.lower_item(item) {
@@ -624,7 +624,7 @@ impl<'a> LoweringContext<'a> {
                 }
             }
 
-            fn visit_trait_item(&mut self, item: &'lcx TraitItem) {
+            fn visit_trait_item(&mut self, item: &'tcx TraitItem) {
                 self.lctx.with_hir_id_owner(item.id, |lctx| {
                     let hir_item = lctx.lower_trait_item(item);
                     let id = hir::TraitItemId { hir_id: hir_item.hir_id };
@@ -635,7 +635,7 @@ impl<'a> LoweringContext<'a> {
                 visit::walk_trait_item(self, item);
             }
 
-            fn visit_impl_item(&mut self, item: &'lcx ImplItem) {
+            fn visit_impl_item(&mut self, item: &'tcx ImplItem) {
                 self.lctx.with_hir_id_owner(item.id, |lctx| {
                     let hir_item = lctx.lower_impl_item(item);
                     let id = hir::ImplItemId { hir_id: hir_item.hir_id };

src/librustc/hir/upvars.rs

@@ -55,7 +55,7 @@ impl Visitor<'tcx> for LocalCollector {
 }
 
 struct CaptureCollector<'a, 'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     locals: &'a FxHashSet<HirId>,
     upvars: FxIndexMap<HirId, hir::Upvar>,
 }

src/librustc/ich/hcx.rs

@@ -61,12 +61,12 @@ pub enum NodeIdHashingMode {
 /// We could also just store a plain reference to the hir::Crate but we want
 /// to avoid that the crate is used to get untracked access to all of the HIR.
 #[derive(Clone, Copy)]
-struct BodyResolver<'gcx>(&'gcx hir::Crate);
+struct BodyResolver<'tcx>(&'tcx hir::Crate);
 
-impl<'gcx> BodyResolver<'gcx> {
+impl<'tcx> BodyResolver<'tcx> {
     // Return a reference to the hir::Body with the given BodyId.
     // DOES NOT DO ANY TRACKING, use carefully.
-    fn body(self, id: hir::BodyId) -> &'gcx hir::Body {
+    fn body(self, id: hir::BodyId) -> &'tcx hir::Body {
         self.0.body(id)
     }
 }
@@ -205,8 +205,8 @@ for &'b mut T {
     }
 }
 
-impl StableHashingContextProvider<'lcx> for TyCtxt<'gcx, 'lcx> {
-    fn get_stable_hashing_context(&self) -> StableHashingContext<'lcx> {
+impl StableHashingContextProvider<'tcx> for TyCtxt<'tcx> {
+    fn get_stable_hashing_context(&self) -> StableHashingContext<'tcx> {
         (*self).create_stable_hashing_context()
     }
 }

src/librustc/ich/impls_syntax.rs

@@ -508,9 +508,9 @@ fn stable_non_narrow_char(swc: ::syntax_pos::NonNarrowChar,
 
 
 
-impl<'gcx> HashStable<StableHashingContext<'gcx>> for feature_gate::Features {
+impl<'tcx> HashStable<StableHashingContext<'tcx>> for feature_gate::Features {
     fn hash_stable<W: StableHasherResult>(&self,
-                                          hcx: &mut StableHashingContext<'gcx>,
+                                          hcx: &mut StableHashingContext<'tcx>,
                                           hasher: &mut StableHasher<W>) {
         // Unfortunately we cannot exhaustively list fields here, since the
         // struct is macro generated.

src/librustc/ich/impls_ty.rs

@@ -11,8 +11,8 @@ use crate::middle::region;
 use crate::ty;
 use crate::mir;
 
-impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>>
-for &'gcx ty::List<T>
+impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>>
+for &'tcx ty::List<T>
     where T: HashStable<StableHashingContext<'a>> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
@@ -40,7 +40,7 @@ for &'gcx ty::List<T>
     }
 }
 
-impl<'a, 'gcx, T> ToStableHashKey<StableHashingContext<'a>> for &'gcx ty::List<T>
+impl<'a, 'tcx, T> ToStableHashKey<StableHashingContext<'a>> for &'tcx ty::List<T>
     where T: HashStable<StableHashingContext<'a>>
 {
     type KeyType = Fingerprint;
@@ -54,7 +54,7 @@ impl<'a, 'gcx, T> ToStableHashKey<StableHashingContext<'a>> for &'gcx ty::List<T
     }
 }
 
-impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::subst::Kind<'gcx> {
+impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::subst::Kind<'tcx> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
@@ -117,19 +117,19 @@ impl<'a> HashStable<StableHashingContext<'a>> for ty::RegionVid {
     }
 }
 
-impl<'gcx, 'tcx> HashStable<StableHashingContext<'gcx>> for ty::ConstVid<'tcx> {
+impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::ConstVid<'tcx> {
     #[inline]
     fn hash_stable<W: StableHasherResult>(&self,
-                                          hcx: &mut StableHashingContext<'gcx>,
+                                          hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
         self.index.hash_stable(hcx, hasher);
     }
 }
 
-impl<'gcx> HashStable<StableHashingContext<'gcx>> for ty::BoundVar {
+impl<'tcx> HashStable<StableHashingContext<'tcx>> for ty::BoundVar {
     #[inline]
     fn hash_stable<W: StableHasherResult>(&self,
-                                          hcx: &mut StableHashingContext<'gcx>,
+                                          hcx: &mut StableHashingContext<'tcx>,
                                           hasher: &mut StableHasher<W>) {
         self.index().hash_stable(hcx, hasher);
     }

src/librustc/infer/at.rs

@@ -30,24 +30,24 @@ use super::*;
 use crate::ty::Const;
 use crate::ty::relate::{Relate, TypeRelation};
 
-pub struct At<'a, 'gcx: 'tcx, 'tcx: 'a> {
-    pub infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+pub struct At<'a, 'tcx: 'a> {
+    pub infcx: &'a InferCtxt<'a, 'tcx>,
     pub cause: &'a ObligationCause<'tcx>,
     pub param_env: ty::ParamEnv<'tcx>,
 }
 
-pub struct Trace<'a, 'gcx: 'tcx, 'tcx: 'a> {
-    at: At<'a, 'gcx, 'tcx>,
+pub struct Trace<'a, 'tcx: 'a> {
+    at: At<'a, 'tcx>,
     a_is_expected: bool,
     trace: TypeTrace<'tcx>,
 }
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     #[inline]
     pub fn at(&'a self,
               cause: &'a ObligationCause<'tcx>,
               param_env: ty::ParamEnv<'tcx>)
-              -> At<'a, 'gcx, 'tcx>
+              -> At<'a, 'tcx>
     {
         At { infcx: self, cause, param_env }
     }
@@ -61,7 +61,7 @@ pub trait ToTrace<'tcx>: Relate<'tcx> + Copy {
                 -> TypeTrace<'tcx>;
 }
 
-impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> At<'a, 'tcx> {
     /// Hacky routine for equating two impl headers in coherence.
     pub fn eq_impl_headers(self,
                            expected: &ty::ImplHeader<'tcx>,
@@ -189,7 +189,7 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
     pub fn trace<T>(self,
                     expected: T,
                     actual: T)
-                    -> Trace<'a, 'gcx, 'tcx>
+                    -> Trace<'a, 'tcx>
         where T: ToTrace<'tcx>
     {
         self.trace_exp(true, expected, actual)
@@ -202,7 +202,7 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
                         a_is_expected: bool,
                         a: T,
                         b: T)
-                        -> Trace<'a, 'gcx, 'tcx>
+                        -> Trace<'a, 'tcx>
         where T: ToTrace<'tcx>
     {
         let trace = ToTrace::to_trace(self.cause, a_is_expected, a, b);
@@ -210,7 +210,7 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> Trace<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> Trace<'a, 'tcx> {
     /// Makes `a <: b` where `a` may or may not be expected (if
     /// `a_is_expected` is true, then `a` is expected).
     /// Makes `expected <: actual`.

src/librustc/infer/canonical/canonicalizer.rs

@@ -21,7 +21,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::indexed_vec::Idx;
 use smallvec::SmallVec;
 
-impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// Canonicalizes a query value `V`. When we canonicalize a query,
     /// we not only canonicalize unbound inference variables, but we
     /// *also* replace all free regions whatsoever. So for example a
@@ -41,9 +41,9 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
         &self,
         value: &V,
         query_state: &mut OriginalQueryValues<'tcx>,
-    ) -> Canonicalized<'gcx, V>
+    ) -> Canonicalized<'tcx, V>
     where
-        V: TypeFoldable<'tcx> + Lift<'gcx>,
+        V: TypeFoldable<'tcx> + Lift<'tcx>,
     {
         self.tcx
             .sess
@@ -85,9 +85,9 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     /// out the [chapter in the rustc guide][c].
     ///
     /// [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html#canonicalizing-the-query-result
-    pub fn canonicalize_response<V>(&self, value: &V) -> Canonicalized<'gcx, V>
+    pub fn canonicalize_response<V>(&self, value: &V) -> Canonicalized<'tcx, V>
     where
-        V: TypeFoldable<'tcx> + Lift<'gcx>,
+        V: TypeFoldable<'tcx> + Lift<'tcx>,
     {
         let mut query_state = OriginalQueryValues::default();
         Canonicalizer::canonicalize(
@@ -99,9 +99,9 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
         )
     }
 
-    pub fn canonicalize_user_type_annotation<V>(&self, value: &V) -> Canonicalized<'gcx, V>
+    pub fn canonicalize_user_type_annotation<V>(&self, value: &V) -> Canonicalized<'tcx, V>
     where
-        V: TypeFoldable<'tcx> + Lift<'gcx>,
+        V: TypeFoldable<'tcx> + Lift<'tcx>,
     {
         let mut query_state = OriginalQueryValues::default();
         Canonicalizer::canonicalize(
@@ -130,9 +130,9 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
         &self,
         value: &V,
         query_state: &mut OriginalQueryValues<'tcx>,
-    ) -> Canonicalized<'gcx, V>
+    ) -> Canonicalized<'tcx, V>
     where
-        V: TypeFoldable<'tcx> + Lift<'gcx>,
+        V: TypeFoldable<'tcx> + Lift<'tcx>,
     {
         self.tcx
             .sess
@@ -160,7 +160,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
 trait CanonicalizeRegionMode {
     fn canonicalize_free_region(
         &self,
-        canonicalizer: &mut Canonicalizer<'_, '_, 'tcx>,
+        canonicalizer: &mut Canonicalizer<'_, 'tcx>,
         r: ty::Region<'tcx>,
     ) -> ty::Region<'tcx>;
 
@@ -172,7 +172,7 @@ struct CanonicalizeQueryResponse;
 impl CanonicalizeRegionMode for CanonicalizeQueryResponse {
     fn canonicalize_free_region(
         &self,
-        canonicalizer: &mut Canonicalizer<'_, '_, 'tcx>,
+        canonicalizer: &mut Canonicalizer<'_, 'tcx>,
         r: ty::Region<'tcx>,
     ) -> ty::Region<'tcx> {
         match r {
@@ -221,7 +221,7 @@ struct CanonicalizeUserTypeAnnotation;
 impl CanonicalizeRegionMode for CanonicalizeUserTypeAnnotation {
     fn canonicalize_free_region(
         &self,
-        canonicalizer: &mut Canonicalizer<'_, '_, 'tcx>,
+        canonicalizer: &mut Canonicalizer<'_, 'tcx>,
         r: ty::Region<'tcx>,
     ) -> ty::Region<'tcx> {
         match r {
@@ -244,7 +244,7 @@ struct CanonicalizeAllFreeRegions;
 impl CanonicalizeRegionMode for CanonicalizeAllFreeRegions {
     fn canonicalize_free_region(
         &self,
-        canonicalizer: &mut Canonicalizer<'_, '_, 'tcx>,
+        canonicalizer: &mut Canonicalizer<'_, 'tcx>,
         r: ty::Region<'tcx>,
     ) -> ty::Region<'tcx> {
         canonicalizer.canonical_var_for_region_in_root_universe(r)
@@ -260,7 +260,7 @@ struct CanonicalizeFreeRegionsOtherThanStatic;
 impl CanonicalizeRegionMode for CanonicalizeFreeRegionsOtherThanStatic {
     fn canonicalize_free_region(
         &self,
-        canonicalizer: &mut Canonicalizer<'_, '_, 'tcx>,
+        canonicalizer: &mut Canonicalizer<'_, 'tcx>,
         r: ty::Region<'tcx>,
     ) -> ty::Region<'tcx> {
         if let ty::ReStatic = r {
@@ -275,9 +275,9 @@ impl CanonicalizeRegionMode for CanonicalizeFreeRegionsOtherThanStatic {
     }
 }
 
-struct Canonicalizer<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
-    infcx: Option<&'cx InferCtxt<'cx, 'gcx, 'tcx>>,
-    tcx: TyCtxt<'gcx, 'tcx>,
+struct Canonicalizer<'cx, 'tcx: 'cx> {
+    infcx: Option<&'cx InferCtxt<'cx, 'tcx>>,
+    tcx: TyCtxt<'tcx>,
     variables: SmallVec<[CanonicalVarInfo; 8]>,
     query_state: &'cx mut OriginalQueryValues<'tcx>,
     // Note that indices is only used once `var_values` is big enough to be
@@ -289,8 +289,8 @@ struct Canonicalizer<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
     binder_index: ty::DebruijnIndex,
 }
 
-impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for Canonicalizer<'cx, 'gcx, 'tcx> {
-    fn tcx<'b>(&'b self) -> TyCtxt<'gcx, 'tcx> {
+impl<'cx, 'tcx> TypeFolder<'tcx> for Canonicalizer<'cx, 'tcx> {
+    fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.tcx
     }
 
@@ -495,18 +495,18 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for Canonicalizer<'cx, 'gcx, 'tcx>
     }
 }
 
-impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> Canonicalizer<'cx, 'tcx> {
     /// The main `canonicalize` method, shared impl of
     /// `canonicalize_query` and `canonicalize_response`.
     fn canonicalize<V>(
         value: &V,
-        infcx: Option<&InferCtxt<'_, 'gcx, 'tcx>>,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        infcx: Option<&InferCtxt<'_, 'tcx>>,
+        tcx: TyCtxt<'tcx>,
         canonicalize_region_mode: &dyn CanonicalizeRegionMode,
         query_state: &mut OriginalQueryValues<'tcx>,
-    ) -> Canonicalized<'gcx, V>
+    ) -> Canonicalized<'tcx, V>
     where
-        V: TypeFoldable<'tcx> + Lift<'gcx>,
+        V: TypeFoldable<'tcx> + Lift<'tcx>,
     {
         let needs_canonical_flags = if canonicalize_region_mode.any() {
             TypeFlags::KEEP_IN_LOCAL_TCX |

src/librustc/infer/canonical/mod.rs

@@ -44,15 +44,15 @@ mod substitute;
 /// variables have been rewritten to "canonical vars". These are
 /// numbered starting from 0 in order of first appearance.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcDecodable, RustcEncodable, HashStable)]
-pub struct Canonical<'gcx, V> {
+pub struct Canonical<'tcx, V> {
     pub max_universe: ty::UniverseIndex,
-    pub variables: CanonicalVarInfos<'gcx>,
+    pub variables: CanonicalVarInfos<'tcx>,
     pub value: V,
 }
 
-pub type CanonicalVarInfos<'gcx> = &'gcx List<CanonicalVarInfo>;
+pub type CanonicalVarInfos<'tcx> = &'tcx List<CanonicalVarInfo>;
 
-impl<'gcx> UseSpecializedDecodable for CanonicalVarInfos<'gcx> {}
+impl<'tcx> UseSpecializedDecodable for CanonicalVarInfos<'tcx> {}
 
 /// A set of values corresponding to the canonical variables from some
 /// `Canonical`. You can give these values to
@@ -194,10 +194,10 @@ pub struct QueryResponse<'tcx, R> {
     pub value: R,
 }
 
-pub type Canonicalized<'gcx, V> = Canonical<'gcx, <V as Lift<'gcx>>::Lifted>;
+pub type Canonicalized<'tcx, V> = Canonical<'tcx, <V as Lift<'tcx>>::Lifted>;
 
-pub type CanonicalizedQueryResponse<'gcx, T> =
-    &'gcx Canonical<'gcx, QueryResponse<'gcx, <T as Lift<'gcx>>::Lifted>>;
+pub type CanonicalizedQueryResponse<'tcx, T> =
+    &'tcx Canonical<'tcx, QueryResponse<'tcx, <T as Lift<'tcx>>::Lifted>>;
 
 /// Indicates whether or not we were able to prove the query to be
 /// true.
@@ -254,7 +254,7 @@ impl<'tcx, R> Canonical<'tcx, QueryResponse<'tcx, R>> {
     }
 }
 
-impl<'gcx, V> Canonical<'gcx, V> {
+impl<'tcx, V> Canonical<'tcx, V> {
     /// Allows you to map the `value` of a canonical while keeping the
     /// same set of bound variables.
     ///
@@ -278,7 +278,7 @@ impl<'gcx, V> Canonical<'gcx, V> {
     /// let ty: Ty<'tcx> = ...;
     /// let b: Canonical<'tcx, (T, Ty<'tcx>)> = a.unchecked_map(|v| (v, ty));
     /// ```
-    pub fn unchecked_map<W>(self, map_op: impl FnOnce(V) -> W) -> Canonical<'gcx, W> {
+    pub fn unchecked_map<W>(self, map_op: impl FnOnce(V) -> W) -> Canonical<'tcx, W> {
         let Canonical {
             max_universe,
             variables,
@@ -294,7 +294,7 @@ impl<'gcx, V> Canonical<'gcx, V> {
 
 pub type QueryRegionConstraint<'tcx> = ty::Binder<ty::OutlivesPredicate<Kind<'tcx>, Region<'tcx>>>;
 
-impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// Creates a substitution S for the canonical value with fresh
     /// inference variables and applies it to the canonical value.
     /// Returns both the instantiated result *and* the substitution S.
@@ -478,7 +478,7 @@ impl<'tcx> CanonicalVarValues<'tcx> {
     /// `self.var_values == [Type(u32), Lifetime('a), Type(u64)]`
     /// we'll return a substitution `subst` with:
     /// `subst.var_values == [Type(^0), Lifetime(^1), Type(^2)]`.
-    pub fn make_identity(&self, tcx: TyCtxt<'tcx, 'tcx>) -> Self {
+    pub fn make_identity(&self, tcx: TyCtxt<'tcx>) -> Self {
         use crate::ty::subst::UnpackedKind;
 
         CanonicalVarValues {

src/librustc/infer/canonical/query_response.rs

@@ -29,7 +29,7 @@ use crate::ty::subst::{Kind, UnpackedKind};
 use crate::ty::{self, BoundVar, InferConst, Lift, Ty, TyCtxt};
 use crate::util::captures::Captures;
 
-impl<'gcx, 'tcx> InferCtxtBuilder<'gcx, 'tcx> {
+impl<'tcx> InferCtxtBuilder<'tcx> {
     /// The "main method" for a canonicalized trait query. Given the
     /// canonical key `canonical_key`, this method will create a new
     /// inference context, instantiate the key, and run your operation
@@ -42,20 +42,20 @@ impl<'gcx, 'tcx> InferCtxtBuilder<'gcx, 'tcx> {
     ///
     /// (It might be mildly nicer to implement this on `TyCtxt`, and
     /// not `InferCtxtBuilder`, but that is a bit tricky right now.
-    /// In part because we would need a `for<'gcx: 'tcx>` sort of
+    /// In part because we would need a `for<'tcx>` sort of
     /// bound for the closure and in part because it is convenient to
     /// have `'tcx` be free on this function so that we can talk about
     /// `K: TypeFoldable<'tcx>`.)
     pub fn enter_canonical_trait_query<K, R>(
-        &'tcx mut self,
+        &mut self,
         canonical_key: &Canonical<'tcx, K>,
-        operation: impl FnOnce(&InferCtxt<'_, 'gcx, 'tcx>, &mut dyn TraitEngine<'tcx>, K)
+        operation: impl FnOnce(&InferCtxt<'_, 'tcx>, &mut dyn TraitEngine<'tcx>, K)
             -> Fallible<R>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, R>>
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, R>>
     where
         K: TypeFoldable<'tcx>,
-        R: Debug + Lift<'gcx> + TypeFoldable<'tcx>,
-        Canonical<'gcx, <QueryResponse<'gcx, R> as Lift<'gcx>>::Lifted>: ArenaAllocatable,
+        R: Debug + Lift<'tcx> + TypeFoldable<'tcx>,
+        Canonical<'tcx, <QueryResponse<'tcx, R> as Lift<'tcx>>::Lifted>: ArenaAllocatable,
     {
         self.enter_with_canonical(
             DUMMY_SP,
@@ -73,7 +73,7 @@ impl<'gcx, 'tcx> InferCtxtBuilder<'gcx, 'tcx> {
     }
 }
 
-impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// This method is meant to be invoked as the final step of a canonical query
     /// implementation. It is given:
     ///
@@ -98,10 +98,10 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
         inference_vars: CanonicalVarValues<'tcx>,
         answer: T,
         fulfill_cx: &mut dyn TraitEngine<'tcx>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, T>>
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, T>>
     where
-        T: Debug + Lift<'gcx> + TypeFoldable<'tcx>,
-        Canonical<'gcx, <QueryResponse<'gcx, T> as Lift<'gcx>>::Lifted>: ArenaAllocatable,
+        T: Debug + Lift<'tcx> + TypeFoldable<'tcx>,
+        Canonical<'tcx, <QueryResponse<'tcx, T> as Lift<'tcx>>::Lifted>: ArenaAllocatable,
     {
         let query_response = self.make_query_response(inference_vars, answer, fulfill_cx)?;
         let canonical_result = self.canonicalize_response(&query_response);
@@ -127,9 +127,9 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
         &self,
         inference_vars: CanonicalVarValues<'tcx>,
         answer: T
-    ) -> Canonical<'gcx, QueryResponse<'gcx, <T as Lift<'gcx>>::Lifted>>
+    ) -> Canonical<'tcx, QueryResponse<'tcx, <T as Lift<'tcx>>::Lifted>>
     where
-        T: Debug + Lift<'gcx> + TypeFoldable<'tcx>,
+        T: Debug + Lift<'tcx> + TypeFoldable<'tcx>,
     {
         self.canonicalize_response(&QueryResponse {
             var_values: inference_vars,
@@ -148,7 +148,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
         fulfill_cx: &mut dyn TraitEngine<'tcx>,
     ) -> Result<QueryResponse<'tcx, T>, NoSolution>
     where
-        T: Debug + TypeFoldable<'tcx> + Lift<'gcx>,
+        T: Debug + TypeFoldable<'tcx> + Lift<'tcx>,
     {
         let tcx = self.tcx;
 
@@ -567,7 +567,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         unsubstituted_region_constraints: &'a [QueryRegionConstraint<'tcx>],
         result_subst: &'a CanonicalVarValues<'tcx>,
-    ) -> impl Iterator<Item = PredicateObligation<'tcx>> + 'a + Captures<'gcx> {
+    ) -> impl Iterator<Item = PredicateObligation<'tcx>> + 'a + Captures<'tcx> {
         unsubstituted_region_constraints
             .iter()
             .map(move |constraint| {
@@ -647,7 +647,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
 /// Given the region obligations and constraints scraped from the infcx,
 /// creates query region constraints.
 pub fn make_query_outlives<'tcx>(
-    tcx: TyCtxt<'_, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     outlives_obligations: impl Iterator<Item = (Ty<'tcx>, ty::Region<'tcx>)>,
     region_constraints: &RegionConstraintData<'tcx>,
 ) -> Vec<QueryRegionConstraint<'tcx>> {

src/librustc/infer/canonical/substitute.rs

@@ -14,7 +14,7 @@ use crate::ty::{self, TyCtxt};
 impl<'tcx, V> Canonical<'tcx, V> {
     /// Instantiate the wrapped value, replacing each canonical value
     /// with the value given in `var_values`.
-    pub fn substitute(&self, tcx: TyCtxt<'_, 'tcx>, var_values: &CanonicalVarValues<'tcx>) -> V
+    pub fn substitute(&self, tcx: TyCtxt<'tcx>, var_values: &CanonicalVarValues<'tcx>) -> V
     where
         V: TypeFoldable<'tcx>,
     {
@@ -29,7 +29,7 @@ impl<'tcx, V> Canonical<'tcx, V> {
     /// V, replacing each of the canonical variables.
     pub fn substitute_projected<T>(
         &self,
-        tcx: TyCtxt<'_, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         var_values: &CanonicalVarValues<'tcx>,
         projection_fn: impl FnOnce(&V) -> &T,
     ) -> T
@@ -46,7 +46,7 @@ impl<'tcx, V> Canonical<'tcx, V> {
 /// must be values for the set of canonical variables that appear in
 /// `value`.
 pub(super) fn substitute_value<'a, 'tcx, T>(
-    tcx: TyCtxt<'_, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     var_values: &CanonicalVarValues<'tcx>,
     value: &'a T,
 ) -> T

src/librustc/infer/combine.rs

@@ -44,8 +44,8 @@ use syntax::ast;
 use syntax_pos::{Span, DUMMY_SP};
 
 #[derive(Clone)]
-pub struct CombineFields<'infcx, 'gcx: 'infcx+'tcx, 'tcx: 'infcx> {
-    pub infcx: &'infcx InferCtxt<'infcx, 'gcx, 'tcx>,
+pub struct CombineFields<'infcx, 'tcx: 'infcx> {
+    pub infcx: &'infcx InferCtxt<'infcx, 'tcx>,
     pub trace: TypeTrace<'tcx>,
     pub cause: Option<ty::relate::Cause>,
     pub param_env: ty::ParamEnv<'tcx>,
@@ -57,7 +57,7 @@ pub enum RelationDir {
     SubtypeOf, SupertypeOf, EqTo
 }
 
-impl<'infcx, 'gcx, 'tcx> InferCtxt<'infcx, 'gcx, 'tcx> {
+impl<'infcx, 'tcx> InferCtxt<'infcx, 'tcx> {
     pub fn super_combine_tys<R>(
         &self,
         relation: &mut R,
@@ -65,7 +65,7 @@ impl<'infcx, 'gcx, 'tcx> InferCtxt<'infcx, 'gcx, 'tcx> {
         b: Ty<'tcx>,
     ) -> RelateResult<'tcx, Ty<'tcx>>
     where
-        R: TypeRelation<'gcx, 'tcx>,
+        R: TypeRelation<'tcx>,
     {
         let a_is_expected = relation.a_is_expected();
 
@@ -125,7 +125,7 @@ impl<'infcx, 'gcx, 'tcx> InferCtxt<'infcx, 'gcx, 'tcx> {
         b: &'tcx ty::Const<'tcx>,
     ) -> RelateResult<'tcx, &'tcx ty::Const<'tcx>>
     where
-        R: TypeRelation<'gcx, 'tcx>,
+        R: TypeRelation<'tcx>,
     {
         let a_is_expected = relation.a_is_expected();
 
@@ -208,24 +208,24 @@ impl<'infcx, 'gcx, 'tcx> InferCtxt<'infcx, 'gcx, 'tcx> {
     }
 }
 
-impl<'infcx, 'gcx, 'tcx> CombineFields<'infcx, 'gcx, 'tcx> {
-    pub fn tcx(&self) -> TyCtxt<'gcx, 'tcx> {
+impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> {
+    pub fn tcx(&self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 
-    pub fn equate<'a>(&'a mut self, a_is_expected: bool) -> Equate<'a, 'infcx, 'gcx, 'tcx> {
+    pub fn equate<'a>(&'a mut self, a_is_expected: bool) -> Equate<'a, 'infcx, 'tcx> {
         Equate::new(self, a_is_expected)
     }
 
-    pub fn sub<'a>(&'a mut self, a_is_expected: bool) -> Sub<'a, 'infcx, 'gcx, 'tcx> {
+    pub fn sub<'a>(&'a mut self, a_is_expected: bool) -> Sub<'a, 'infcx, 'tcx> {
         Sub::new(self, a_is_expected)
     }
 
-    pub fn lub<'a>(&'a mut self, a_is_expected: bool) -> Lub<'a, 'infcx, 'gcx, 'tcx> {
+    pub fn lub<'a>(&'a mut self, a_is_expected: bool) -> Lub<'a, 'infcx, 'tcx> {
         Lub::new(self, a_is_expected)
     }
 
-    pub fn glb<'a>(&'a mut self, a_is_expected: bool) -> Glb<'a, 'infcx, 'gcx, 'tcx> {
+    pub fn glb<'a>(&'a mut self, a_is_expected: bool) -> Glb<'a, 'infcx, 'tcx> {
         Glb::new(self, a_is_expected)
     }
 
@@ -355,8 +355,8 @@ impl<'infcx, 'gcx, 'tcx> CombineFields<'infcx, 'gcx, 'tcx> {
     }
 }
 
-struct Generalizer<'cx, 'gcx: 'cx+'tcx, 'tcx: 'cx> {
-    infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
+struct Generalizer<'cx, 'tcx: 'cx> {
+    infcx: &'cx InferCtxt<'cx, 'tcx>,
 
     /// The span, used when creating new type variables and things.
     span: Span,
@@ -415,8 +415,8 @@ struct Generalization<'tcx> {
     needs_wf: bool,
 }
 
-impl TypeRelation<'gcx, 'tcx> for Generalizer<'_, 'gcx, 'tcx> {
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> {
+impl TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 

src/librustc/infer/equate.rs

@@ -11,23 +11,23 @@ use crate::mir::interpret::ConstValue;
 use crate::infer::unify_key::replace_if_possible;
 
 /// Ensures `a` is made equal to `b`. Returns `a` on success.
-pub struct Equate<'combine, 'infcx: 'combine, 'gcx: 'infcx+'tcx, 'tcx: 'infcx> {
-    fields: &'combine mut CombineFields<'infcx, 'gcx, 'tcx>,
+pub struct Equate<'combine, 'infcx: 'combine, 'tcx: 'infcx> {
+    fields: &'combine mut CombineFields<'infcx, 'tcx>,
     a_is_expected: bool,
 }
 
-impl<'combine, 'infcx, 'gcx, 'tcx> Equate<'combine, 'infcx, 'gcx, 'tcx> {
-    pub fn new(fields: &'combine mut CombineFields<'infcx, 'gcx, 'tcx>, a_is_expected: bool)
-        -> Equate<'combine, 'infcx, 'gcx, 'tcx>
+impl<'combine, 'infcx, 'tcx> Equate<'combine, 'infcx, 'tcx> {
+    pub fn new(fields: &'combine mut CombineFields<'infcx, 'tcx>, a_is_expected: bool)
+        -> Equate<'combine, 'infcx, 'tcx>
     {
         Equate { fields: fields, a_is_expected: a_is_expected }
     }
 }
 
-impl TypeRelation<'gcx, 'tcx> for Equate<'combine, 'infcx, 'gcx, 'tcx> {
+impl TypeRelation<'tcx> for Equate<'combine, 'infcx, 'tcx> {
     fn tag(&self) -> &'static str { "Equate" }
 
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> { self.fields.tcx() }
+    fn tcx(&self) -> TyCtxt<'tcx> { self.fields.tcx() }
 
     fn a_is_expected(&self) -> bool { self.a_is_expected }
 

src/librustc/infer/error_reporting/mod.rs

@@ -67,7 +67,7 @@ mod need_type_info;
 
 pub mod nice_region_error;
 
-impl<'gcx, 'tcx> TyCtxt<'gcx, 'tcx> {
+impl<'tcx> TyCtxt<'tcx> {
     pub fn note_and_explain_region(
         self,
         region_scope_tree: &region::ScopeTree,
@@ -282,7 +282,7 @@ impl<'gcx, 'tcx> TyCtxt<'gcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn report_region_errors(
         &self,
         region_scope_tree: &region::ScopeTree,
@@ -445,13 +445,13 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         use ty::print::Printer;
         use ty::subst::Kind;
 
-        struct AbsolutePathPrinter<'gcx, 'tcx> {
-            tcx: TyCtxt<'gcx, 'tcx>,
+        struct AbsolutePathPrinter<'tcx> {
+            tcx: TyCtxt<'tcx>,
         }
 
         struct NonTrivialPath;
 
-        impl<'gcx, 'tcx> Printer<'gcx, 'tcx> for AbsolutePathPrinter<'gcx, 'tcx> {
+        impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
             type Error = NonTrivialPath;
 
             type Path = Vec<String>;
@@ -460,7 +460,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             type DynExistential = !;
             type Const = !;
 
-            fn tcx<'a>(&'a self) -> TyCtxt<'gcx, 'tcx> {
+            fn tcx<'a>(&'a self) -> TyCtxt<'tcx> {
                 self.tcx
             }
 
@@ -1546,7 +1546,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     fn report_inference_failure(
         &self,
         var_origin: RegionVariableOrigin,

src/librustc/infer/error_reporting/need_type_info.rs

@@ -9,16 +9,16 @@ use syntax::source_map::CompilerDesugaringKind;
 use syntax_pos::Span;
 use errors::DiagnosticBuilder;
 
-struct FindLocalByTypeVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+struct FindLocalByTypeVisitor<'a, 'tcx> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
     target_ty: Ty<'tcx>,
-    hir_map: &'a hir::map::Map<'gcx>,
-    found_local_pattern: Option<&'gcx Pat>,
-    found_arg_pattern: Option<&'gcx Pat>,
+    hir_map: &'a hir::map::Map<'tcx>,
+    found_local_pattern: Option<&'tcx Pat>,
+    found_arg_pattern: Option<&'tcx Pat>,
     found_ty: Option<Ty<'tcx>>,
 }
 
-impl<'a, 'gcx, 'tcx> FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> FindLocalByTypeVisitor<'a, 'tcx> {
     fn node_matches_type(&mut self, hir_id: HirId) -> Option<Ty<'tcx>> {
         let ty_opt = self.infcx.in_progress_tables.and_then(|tables| {
             tables.borrow().node_type_opt(hir_id)
@@ -47,12 +47,12 @@ impl<'a, 'gcx, 'tcx> FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> Visitor<'gcx> for FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
-    fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'gcx> {
+impl<'a, 'tcx> Visitor<'tcx> for FindLocalByTypeVisitor<'a, 'tcx> {
+    fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
         NestedVisitorMap::OnlyBodies(&self.hir_map)
     }
 
-    fn visit_local(&mut self, local: &'gcx Local) {
+    fn visit_local(&mut self, local: &'tcx Local) {
         if let (None, Some(ty)) = (self.found_local_pattern, self.node_matches_type(local.hir_id)) {
             self.found_local_pattern = Some(&*local.pat);
             self.found_ty = Some(ty);
@@ -60,7 +60,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
         intravisit::walk_local(self, local);
     }
 
-    fn visit_body(&mut self, body: &'gcx Body) {
+    fn visit_body(&mut self, body: &'tcx Body) {
         for argument in &body.arguments {
             if let (None, Some(ty)) = (
                 self.found_arg_pattern,
@@ -75,7 +75,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
 }
 
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn extract_type_name(
         &self,
         ty: Ty<'tcx>,
@@ -103,7 +103,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         body_id: Option<hir::BodyId>,
         span: Span,
         ty: Ty<'tcx>
-    ) -> DiagnosticBuilder<'gcx> {
+    ) -> DiagnosticBuilder<'tcx> {
         let ty = self.resolve_vars_if_possible(&ty);
         let name = self.extract_type_name(&ty, None);
 
@@ -230,7 +230,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         &self,
         span: Span,
         ty: Ty<'tcx>
-    ) -> DiagnosticBuilder<'gcx> {
+    ) -> DiagnosticBuilder<'tcx> {
         let ty = self.resolve_vars_if_possible(&ty);
         let name = self.extract_type_name(&ty, None);
 

src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs

@@ -5,7 +5,7 @@ use crate::infer::error_reporting::nice_region_error::NiceRegionError;
 use crate::infer::error_reporting::nice_region_error::util::AnonymousArgInfo;
 use crate::util::common::ErrorReported;
 
-impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     /// Print the error message for lifetime errors when both the concerned regions are anonymous.
     ///
     /// Consider a case where we have

src/librustc/infer/error_reporting/nice_region_error/find_anon_type.rs

@@ -5,7 +5,7 @@ use crate::middle::resolve_lifetime as rl;
 use crate::hir::intravisit::{self, NestedVisitorMap, Visitor};
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
 
-impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     /// This function calls the `visit_ty` method for the parameters
     /// corresponding to the anonymous regions. The `nested_visitor.found_type`
     /// contains the anonymous type.
@@ -60,9 +60,9 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
     // to the anonymous region.
     fn find_component_for_bound_region(
         &self,
-        arg: &'gcx hir::Ty,
+        arg: &'tcx hir::Ty,
         br: &ty::BoundRegion,
-    ) -> Option<(&'gcx hir::Ty)> {
+    ) -> Option<(&'tcx hir::Ty)> {
         let mut nested_visitor = FindNestedTypeVisitor {
             tcx: self.tcx(),
             bound_region: *br,
@@ -81,23 +81,23 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
 // walk the types like &mut Vec<&u8> and &u8 looking for the HIR
 // where that lifetime appears. This allows us to highlight the
 // specific part of the type in the error message.
-struct FindNestedTypeVisitor<'gcx, 'tcx> {
-    tcx: TyCtxt<'gcx, 'tcx>,
+struct FindNestedTypeVisitor<'tcx> {
+    tcx: TyCtxt<'tcx>,
     // The bound_region corresponding to the Refree(freeregion)
     // associated with the anonymous region we are looking for.
     bound_region: ty::BoundRegion,
     // The type where the anonymous lifetime appears
     // for e.g., Vec<`&u8`> and <`&u8`>
-    found_type: Option<&'gcx hir::Ty>,
+    found_type: Option<&'tcx hir::Ty>,
     current_index: ty::DebruijnIndex,
 }
 
-impl Visitor<'gcx> for FindNestedTypeVisitor<'gcx, 'tcx> {
-    fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'gcx> {
+impl Visitor<'tcx> for FindNestedTypeVisitor<'tcx> {
+    fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
         NestedVisitorMap::OnlyBodies(&self.tcx.hir())
     }
 
-    fn visit_ty(&mut self, arg: &'gcx hir::Ty) {
+    fn visit_ty(&mut self, arg: &'tcx hir::Ty) {
         match arg.node {
             hir::TyKind::BareFn(_) => {
                 self.current_index.shift_in(1);
@@ -208,15 +208,15 @@ impl Visitor<'gcx> for FindNestedTypeVisitor<'gcx, 'tcx> {
 // and would walk the types like Vec<Ref> in the above example and Ref looking for the HIR
 // where that lifetime appears. This allows us to highlight the
 // specific part of the type in the error message.
-struct TyPathVisitor<'gcx, 'tcx> {
-    tcx: TyCtxt<'gcx, 'tcx>,
+struct TyPathVisitor<'tcx> {
+    tcx: TyCtxt<'tcx>,
     found_it: bool,
     bound_region: ty::BoundRegion,
     current_index: ty::DebruijnIndex,
 }
 
-impl Visitor<'gcx> for TyPathVisitor<'gcx, 'tcx> {
-    fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'gcx> {
+impl Visitor<'tcx> for TyPathVisitor<'tcx> {
+    fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
         NestedVisitorMap::OnlyBodies(&self.tcx.hir())
     }
 
@@ -267,7 +267,7 @@ impl Visitor<'gcx> for TyPathVisitor<'gcx, 'tcx> {
         }
     }
 
-    fn visit_ty(&mut self, arg: &'gcx hir::Ty) {
+    fn visit_ty(&mut self, arg: &'tcx hir::Ty) {
         // ignore nested types
         //
         // If you have a type like `Foo<'a, &Ty>` we

src/librustc/infer/error_reporting/nice_region_error/mod.rs

@@ -14,7 +14,7 @@ mod outlives_closure;
 mod static_impl_trait;
 mod util;
 
-impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     pub fn try_report_nice_region_error(&self, error: &RegionResolutionError<'tcx>) -> bool {
         match *error {
             ConcreteFailure(..) | SubSupConflict(..) => {}
@@ -30,16 +30,16 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     }
 }
 
-pub struct NiceRegionError<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
-    infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
+pub struct NiceRegionError<'cx, 'tcx: 'cx> {
+    infcx: &'cx InferCtxt<'cx, 'tcx>,
     error: Option<RegionResolutionError<'tcx>>,
     regions: Option<(Span, ty::Region<'tcx>, ty::Region<'tcx>)>,
     tables: Option<&'cx ty::TypeckTables<'tcx>>,
 }
 
-impl<'cx, 'gcx, 'tcx> NiceRegionError<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> NiceRegionError<'cx, 'tcx> {
     pub fn new(
-        infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
+        infcx: &'cx InferCtxt<'cx, 'tcx>,
         error: RegionResolutionError<'tcx>,
         tables: Option<&'cx ty::TypeckTables<'tcx>>,
     ) -> Self {
@@ -47,7 +47,7 @@ impl<'cx, 'gcx, 'tcx> NiceRegionError<'cx, 'gcx, 'tcx> {
     }
 
     pub fn new_from_span(
-        infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
+        infcx: &'cx InferCtxt<'cx, 'tcx>,
         span: Span,
         sub: ty::Region<'tcx>,
         sup: ty::Region<'tcx>,
@@ -56,7 +56,7 @@ impl<'cx, 'gcx, 'tcx> NiceRegionError<'cx, 'gcx, 'tcx> {
         Self { infcx, error: None, regions: Some((span, sub, sup)), tables }
     }
 
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 

src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs

@@ -5,7 +5,7 @@ use crate::hir::{FunctionRetTy, TyKind};
 use crate::ty;
 use errors::{Applicability, DiagnosticBuilder};
 
-impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     /// When given a `ConcreteFailure` for a function with arguments containing a named region and
     /// an anonymous region, emit an descriptive diagnostic error.
     pub(super) fn try_report_named_anon_conflict(&self) -> Option<DiagnosticBuilder<'a>> {

src/librustc/infer/error_reporting/nice_region_error/outlives_closure.rs

@@ -9,7 +9,7 @@ use crate::hir::Node;
 use crate::util::common::ErrorReported;
 use crate::infer::lexical_region_resolve::RegionResolutionError::SubSupConflict;
 
-impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     /// Print the error message for lifetime errors when binding escapes a closure.
     ///
     /// Consider a case where we have

src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs

@@ -13,7 +13,7 @@ use crate::ty::print::{Print, RegionHighlightMode, FmtPrinter};
 
 use std::fmt::{self, Write};
 
-impl NiceRegionError<'me, 'gcx, 'tcx> {
+impl NiceRegionError<'me, 'tcx> {
     /// When given a `ConcreteFailure` for a function with arguments containing a named region and
     /// an anonymous region, emit a descriptive diagnostic error.
     pub(super) fn try_report_placeholder_conflict(&self) -> Option<DiagnosticBuilder<'me>> {
@@ -321,14 +321,14 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
     ) {
         // HACK(eddyb) maybe move this in a more central location.
         #[derive(Copy, Clone)]
-        struct Highlighted<'gcx, 'tcx, T> {
-            tcx: TyCtxt<'gcx, 'tcx>,
+        struct Highlighted<'tcx, T> {
+            tcx: TyCtxt<'tcx>,
             highlight: RegionHighlightMode,
             value: T,
         }
 
-        impl<'gcx, 'tcx, T> Highlighted<'gcx, 'tcx, T> {
-            fn map<U>(self, f: impl FnOnce(T) -> U) -> Highlighted<'gcx, 'tcx, U> {
+        impl<'tcx, T> Highlighted<'tcx, T> {
+            fn map<U>(self, f: impl FnOnce(T) -> U) -> Highlighted<'tcx, U> {
                 Highlighted {
                     tcx: self.tcx,
                     highlight: self.highlight,
@@ -337,12 +337,11 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
             }
         }
 
-        impl<'gcx, 'tcx, T> fmt::Display for Highlighted<'gcx, 'tcx, T>
+        impl<'tcx, T> fmt::Display for Highlighted<'tcx, T>
         where
             T: for<'a, 'b, 'c> Print<
-                'gcx,
                 'tcx,
-                FmtPrinter<'a, 'gcx, 'tcx, &'b mut fmt::Formatter<'c>>,
+                FmtPrinter<'a, 'tcx, &'b mut fmt::Formatter<'c>>,
                 Error = fmt::Error,
             >,
         {

src/librustc/infer/error_reporting/nice_region_error/static_impl_trait.rs

@@ -6,7 +6,7 @@ use crate::ty::{BoundRegion, FreeRegion, RegionKind};
 use crate::util::common::ErrorReported;
 use errors::Applicability;
 
-impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     /// Print the error message for lifetime errors when the return type is a static impl Trait.
     pub(super) fn try_report_static_impl_trait(&self) -> Option<ErrorReported> {
         if let Some(ref error) = self.error {

src/librustc/infer/error_reporting/nice_region_error/util.rs

@@ -24,7 +24,7 @@ pub(super) struct AnonymousArgInfo<'tcx> {
     pub is_first: bool,
 }
 
-impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     // This method walks the Type of the function body arguments using
     // `fold_regions()` function and returns the
     // &hir::Arg of the function argument corresponding to the anonymous

src/librustc/infer/error_reporting/note.rs

@@ -4,7 +4,7 @@ use crate::ty::{self, Region};
 use crate::ty::error::TypeError;
 use errors::DiagnosticBuilder;
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub(super) fn note_region_origin(&self,
                                      err: &mut DiagnosticBuilder<'_>,
                                      origin: &SubregionOrigin<'tcx>) {

src/librustc/infer/freshen.rs

@@ -41,17 +41,17 @@ use std::collections::hash_map::Entry;
 use super::InferCtxt;
 use super::unify_key::ToType;
 
-pub struct TypeFreshener<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+pub struct TypeFreshener<'a, 'tcx: 'a> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
     ty_freshen_count: u32,
     const_freshen_count: u32,
     ty_freshen_map: FxHashMap<ty::InferTy, Ty<'tcx>>,
     const_freshen_map: FxHashMap<ty::InferConst<'tcx>, &'tcx ty::Const<'tcx>>,
 }
 
-impl<'a, 'gcx, 'tcx> TypeFreshener<'a, 'gcx, 'tcx> {
-    pub fn new(infcx: &'a InferCtxt<'a, 'gcx, 'tcx>)
-               -> TypeFreshener<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> TypeFreshener<'a, 'tcx> {
+    pub fn new(infcx: &'a InferCtxt<'a, 'tcx>)
+               -> TypeFreshener<'a, 'tcx> {
         TypeFreshener {
             infcx,
             ty_freshen_count: 0,
@@ -113,8 +113,8 @@ impl<'a, 'gcx, 'tcx> TypeFreshener<'a, 'gcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for TypeFreshener<'a, 'gcx, 'tcx> {
-    fn tcx<'b>(&'b self) -> TyCtxt<'gcx, 'tcx> {
+impl<'a, 'tcx> TypeFolder<'tcx> for TypeFreshener<'a, 'tcx> {
+    fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 

src/librustc/infer/fudge.rs

@@ -22,7 +22,7 @@ fn const_vars_since_snapshot<'tcx>(
     }).collect())
 }
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     /// This rather funky routine is used while processing expected
     /// types. What happens here is that we want to propagate a
     /// coercion through the return type of a fn to its
@@ -133,8 +133,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     }
 }
 
-pub struct InferenceFudger<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+pub struct InferenceFudger<'a, 'tcx: 'a> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
     type_vars: (Range<TyVid>, Vec<TypeVariableOrigin>),
     int_vars: Range<IntVid>,
     float_vars: Range<FloatVid>,
@@ -142,8 +142,8 @@ pub struct InferenceFudger<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     const_vars: (Range<ConstVid<'tcx>>, Vec<ConstVariableOrigin>),
 }
 
-impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for InferenceFudger<'a, 'gcx, 'tcx> {
-    fn tcx<'b>(&'b self) -> TyCtxt<'gcx, 'tcx> {
+impl<'a, 'tcx> TypeFolder<'tcx> for InferenceFudger<'a, 'tcx> {
+    fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 

src/librustc/infer/glb.rs

@@ -8,23 +8,23 @@ use crate::ty::{self, Ty, TyCtxt};
 use crate::ty::relate::{Relate, RelateResult, TypeRelation};
 
 /// "Greatest lower bound" (common subtype)
-pub struct Glb<'combine, 'infcx: 'combine, 'gcx: 'infcx+'tcx, 'tcx: 'infcx> {
-    fields: &'combine mut CombineFields<'infcx, 'gcx, 'tcx>,
+pub struct Glb<'combine, 'infcx: 'combine, 'tcx: 'infcx> {
+    fields: &'combine mut CombineFields<'infcx, 'tcx>,
     a_is_expected: bool,
 }
 
-impl<'combine, 'infcx, 'gcx, 'tcx> Glb<'combine, 'infcx, 'gcx, 'tcx> {
-    pub fn new(fields: &'combine mut CombineFields<'infcx, 'gcx, 'tcx>, a_is_expected: bool)
-        -> Glb<'combine, 'infcx, 'gcx, 'tcx>
+impl<'combine, 'infcx, 'tcx> Glb<'combine, 'infcx, 'tcx> {
+    pub fn new(fields: &'combine mut CombineFields<'infcx, 'tcx>, a_is_expected: bool)
+        -> Glb<'combine, 'infcx, 'tcx>
     {
         Glb { fields: fields, a_is_expected: a_is_expected }
     }
 }
 
-impl TypeRelation<'gcx, 'tcx> for Glb<'combine, 'infcx, 'gcx, 'tcx> {
+impl TypeRelation<'tcx> for Glb<'combine, 'infcx, 'tcx> {
     fn tag(&self) -> &'static str { "Glb" }
 
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> { self.fields.tcx() }
+    fn tcx(&self) -> TyCtxt<'tcx> { self.fields.tcx() }
 
     fn a_is_expected(&self) -> bool { self.a_is_expected }
 
@@ -85,10 +85,10 @@ impl TypeRelation<'gcx, 'tcx> for Glb<'combine, 'infcx, 'gcx, 'tcx> {
     }
 }
 
-impl<'combine, 'infcx, 'gcx, 'tcx> LatticeDir<'infcx, 'gcx, 'tcx>
-    for Glb<'combine, 'infcx, 'gcx, 'tcx>
+impl<'combine, 'infcx, 'tcx> LatticeDir<'infcx, 'tcx>
+    for Glb<'combine, 'infcx, 'tcx>
 {
-    fn infcx(&self) -> &'infcx InferCtxt<'infcx, 'gcx, 'tcx> {
+    fn infcx(&self) -> &'infcx InferCtxt<'infcx, 'tcx> {
         self.fields.infcx
     }
 

src/librustc/infer/higher_ranked/mod.rs

@@ -9,7 +9,7 @@ use crate::ty::relate::{Relate, RelateResult, TypeRelation};
 use crate::ty::{self, Binder, TypeFoldable};
 use crate::mir::interpret::ConstValue;
 
-impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> CombineFields<'a, 'tcx> {
     pub fn higher_ranked_sub<T>(
         &mut self,
         a: &Binder<T>,
@@ -60,7 +60,7 @@ impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     /// Replaces all regions (resp. types) bound by `binder` with placeholder
     /// regions (resp. types) and return a map indicating which bound-region
     /// placeholder region. This is the first step of checking subtyping

src/librustc/infer/lattice.rs

@@ -27,8 +27,8 @@ use crate::ty::TyVar;
 use crate::ty::{self, Ty};
 use crate::ty::relate::{RelateResult, TypeRelation};
 
-pub trait LatticeDir<'f, 'gcx: 'f + 'tcx, 'tcx: 'f>: TypeRelation<'gcx, 'tcx> {
-    fn infcx(&self) -> &'f InferCtxt<'f, 'gcx, 'tcx>;
+pub trait LatticeDir<'f, 'tcx: 'f>: TypeRelation<'tcx> {
+    fn infcx(&self) -> &'f InferCtxt<'f, 'tcx>;
 
     fn cause(&self) -> &ObligationCause<'tcx>;
 
@@ -41,11 +41,11 @@ pub trait LatticeDir<'f, 'gcx: 'f + 'tcx, 'tcx: 'f>: TypeRelation<'gcx, 'tcx> {
     fn relate_bound(&mut self, v: Ty<'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, ()>;
 }
 
-pub fn super_lattice_tys<'a, 'gcx, 'tcx, L>(this: &mut L,
+pub fn super_lattice_tys<'a, 'tcx, L>(this: &mut L,
                                             a: Ty<'tcx>,
                                             b: Ty<'tcx>)
                                             -> RelateResult<'tcx, Ty<'tcx>>
-    where L: LatticeDir<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
+    where L: LatticeDir<'a, 'tcx>, 'tcx: 'a
 {
     debug!("{}.lattice_tys({:?}, {:?})",
            this.tag(),

src/librustc/infer/lexical_region_resolve/graphviz.rs

@@ -44,9 +44,9 @@ graphs will be printed.                                                     \n\
 ");
 }
 
-pub fn maybe_print_constraints_for<'a, 'gcx, 'tcx>(
+pub fn maybe_print_constraints_for<'a, 'tcx>(
     region_data: &RegionConstraintData<'tcx>,
-    region_rels: &RegionRelations<'a, 'gcx, 'tcx>)
+    region_rels: &RegionRelations<'a, 'tcx>)
 {
     let tcx = region_rels.tcx;
     let context = region_rels.context;
@@ -107,9 +107,9 @@ pub fn maybe_print_constraints_for<'a, 'gcx, 'tcx>(
     }
 }
 
-struct ConstraintGraph<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
+struct ConstraintGraph<'a, 'tcx: 'a> {
     graph_name: String,
-    region_rels: &'a RegionRelations<'a, 'gcx, 'tcx>,
+    region_rels: &'a RegionRelations<'a, 'tcx>,
     map: &'a BTreeMap<Constraint<'tcx>, SubregionOrigin<'tcx>>,
     node_ids: FxHashMap<Node, usize>,
 }
@@ -126,11 +126,11 @@ enum Edge<'tcx> {
     EnclScope(region::Scope, region::Scope),
 }
 
-impl<'a, 'gcx, 'tcx> ConstraintGraph<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> ConstraintGraph<'a, 'tcx> {
     fn new(name: String,
-           region_rels: &'a RegionRelations<'a, 'gcx, 'tcx>,
+           region_rels: &'a RegionRelations<'a, 'tcx>,
            map: &'a ConstraintMap<'tcx>)
-           -> ConstraintGraph<'a, 'gcx, 'tcx> {
+           -> ConstraintGraph<'a, 'tcx> {
         let mut i = 0;
         let mut node_ids = FxHashMap::default();
         {
@@ -161,7 +161,7 @@ impl<'a, 'gcx, 'tcx> ConstraintGraph<'a, 'gcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> dot::Labeller<'a> for ConstraintGraph<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> dot::Labeller<'a> for ConstraintGraph<'a, 'tcx> {
     type Node = Node;
     type Edge = Edge<'tcx>;
     fn graph_id(&self) -> dot::Id<'_> {
@@ -215,7 +215,7 @@ fn edge_to_nodes(e: &Edge<'_>) -> (Node, Node) {
     }
 }
 
-impl<'a, 'gcx, 'tcx> dot::GraphWalk<'a> for ConstraintGraph<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> dot::GraphWalk<'a> for ConstraintGraph<'a, 'tcx> {
     type Node = Node;
     type Edge = Edge<'tcx>;
     fn nodes(&self) -> dot::Nodes<'_, Node> {
@@ -246,7 +246,7 @@ impl<'a, 'gcx, 'tcx> dot::GraphWalk<'a> for ConstraintGraph<'a, 'gcx, 'tcx> {
 
 pub type ConstraintMap<'tcx> = BTreeMap<Constraint<'tcx>, SubregionOrigin<'tcx>>;
 
-fn dump_region_data_to<'a, 'gcx, 'tcx>(region_rels: &RegionRelations<'a, 'gcx, 'tcx>,
+fn dump_region_data_to<'a, 'tcx>(region_rels: &RegionRelations<'a, 'tcx>,
                                        map: &ConstraintMap<'tcx>,
                                        path: &str)
                                        -> io::Result<()> {

src/librustc/infer/lexical_region_resolve/mod.rs

@@ -30,7 +30,7 @@ mod graphviz;
 /// assuming such values can be found. It returns the final values of
 /// all the variables as well as a set of errors that must be reported.
 pub fn resolve<'tcx>(
-    region_rels: &RegionRelations<'_, '_, 'tcx>,
+    region_rels: &RegionRelations<'_, 'tcx>,
     var_infos: VarInfos,
     data: RegionConstraintData<'tcx>,
 ) -> (
@@ -96,14 +96,14 @@ struct RegionAndOrigin<'tcx> {
 
 type RegionGraph<'tcx> = Graph<(), Constraint<'tcx>>;
 
-struct LexicalResolver<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
-    region_rels: &'cx RegionRelations<'cx, 'gcx, 'tcx>,
+struct LexicalResolver<'cx, 'tcx: 'cx> {
+    region_rels: &'cx RegionRelations<'cx, 'tcx>,
     var_infos: VarInfos,
     data: RegionConstraintData<'tcx>,
 }
 
-impl<'cx, 'gcx, 'tcx> LexicalResolver<'cx, 'gcx, 'tcx> {
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> {
+impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
         self.region_rels.tcx
     }
 
@@ -136,14 +136,14 @@ impl<'cx, 'gcx, 'tcx> LexicalResolver<'cx, 'gcx, 'tcx> {
 
     /// Initially, the value for all variables is set to `'empty`, the
     /// empty region. The `expansion` phase will grow this larger.
-    fn construct_var_data(&self, tcx: TyCtxt<'_, 'tcx>) -> LexicalRegionResolutions<'tcx> {
+    fn construct_var_data(&self, tcx: TyCtxt<'tcx>) -> LexicalRegionResolutions<'tcx> {
         LexicalRegionResolutions {
             error_region: tcx.lifetimes.re_static,
             values: IndexVec::from_elem_n(VarValue::Value(tcx.lifetimes.re_empty), self.num_vars())
         }
     }
 
-    fn dump_constraints(&self, free_regions: &RegionRelations<'_, '_, 'tcx>) {
+    fn dump_constraints(&self, free_regions: &RegionRelations<'_, 'tcx>) {
         debug!(
             "----() Start constraint listing (context={:?}) ()----",
             free_regions.context
@@ -785,7 +785,7 @@ impl<'tcx> fmt::Debug for RegionAndOrigin<'tcx> {
 }
 
 impl<'tcx> LexicalRegionResolutions<'tcx> {
-    fn normalize<T>(&self, tcx: TyCtxt<'_, 'tcx>, value: T) -> T
+    fn normalize<T>(&self, tcx: TyCtxt<'tcx>, value: T) -> T
     where
         T: TypeFoldable<'tcx>,
     {

src/librustc/infer/lub.rs

@@ -8,23 +8,23 @@ use crate::ty::{self, Ty, TyCtxt};
 use crate::ty::relate::{Relate, RelateResult, TypeRelation};
 
 /// "Least upper bound" (common supertype)
-pub struct Lub<'combine, 'infcx: 'combine, 'gcx: 'infcx+'tcx, 'tcx: 'infcx> {
-    fields: &'combine mut CombineFields<'infcx, 'gcx, 'tcx>,
+pub struct Lub<'combine, 'infcx: 'combine, 'tcx: 'infcx> {
+    fields: &'combine mut CombineFields<'infcx, 'tcx>,
     a_is_expected: bool,
 }
 
-impl<'combine, 'infcx, 'gcx, 'tcx> Lub<'combine, 'infcx, 'gcx, 'tcx> {
-    pub fn new(fields: &'combine mut CombineFields<'infcx, 'gcx, 'tcx>, a_is_expected: bool)
-        -> Lub<'combine, 'infcx, 'gcx, 'tcx>
+impl<'combine, 'infcx, 'tcx> Lub<'combine, 'infcx, 'tcx> {
+    pub fn new(fields: &'combine mut CombineFields<'infcx, 'tcx>, a_is_expected: bool)
+        -> Lub<'combine, 'infcx, 'tcx>
     {
         Lub { fields: fields, a_is_expected: a_is_expected }
     }
 }
 
-impl TypeRelation<'gcx, 'tcx> for Lub<'combine, 'infcx, 'gcx, 'tcx> {
+impl TypeRelation<'tcx> for Lub<'combine, 'infcx, 'tcx> {
     fn tag(&self) -> &'static str { "Lub" }
 
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> { self.fields.tcx() }
+    fn tcx(&self) -> TyCtxt<'tcx> { self.fields.tcx() }
 
     fn a_is_expected(&self) -> bool { self.a_is_expected }
 
@@ -85,10 +85,10 @@ impl TypeRelation<'gcx, 'tcx> for Lub<'combine, 'infcx, 'gcx, 'tcx> {
     }
 }
 
-impl<'combine, 'infcx, 'gcx, 'tcx> LatticeDir<'infcx, 'gcx, 'tcx>
-    for Lub<'combine, 'infcx, 'gcx, 'tcx>
+impl<'combine, 'infcx, 'tcx> LatticeDir<'infcx, 'tcx>
+    for Lub<'combine, 'infcx, 'tcx>
 {
-    fn infcx(&self) -> &'infcx InferCtxt<'infcx, 'gcx, 'tcx> {
+    fn infcx(&self) -> &'infcx InferCtxt<'infcx, 'tcx> {
         self.fields.infcx
     }
 

src/librustc/infer/mod.rs

@@ -91,7 +91,7 @@ impl SuppressRegionErrors {
     /// Indicates that the MIR borrowck will repeat these region
     /// checks, so we should ignore errors if NLL is (unconditionally)
     /// enabled.
-    pub fn when_nll_is_enabled(tcx: TyCtxt<'_, '_>) -> Self {
+    pub fn when_nll_is_enabled(tcx: TyCtxt<'_>) -> Self {
         match tcx.borrowck_mode() {
             // If we're on Migrate mode, report AST region errors
             BorrowckMode::Migrate => SuppressRegionErrors { suppressed: false },
@@ -102,8 +102,8 @@ impl SuppressRegionErrors {
     }
 }
 
-pub struct InferCtxt<'a, 'gcx, 'tcx> {
-    pub tcx: TyCtxt<'gcx, 'tcx>,
+pub struct InferCtxt<'a, 'tcx> {
+    pub tcx: TyCtxt<'tcx>,
 
     /// During type-checking/inference of a body, `in_progress_tables`
     /// contains a reference to the tables being built up, which are
@@ -464,14 +464,14 @@ impl<'tcx> fmt::Display for FixupError<'tcx> {
 
 /// Helper type of a temporary returned by `tcx.infer_ctxt()`.
 /// Necessary because we can't write the following bound:
-/// `F: for<'b, 'tcx> where 'gcx: 'tcx FnOnce(InferCtxt<'b, 'gcx, 'tcx>)`.
-pub struct InferCtxtBuilder<'gcx: 'tcx, 'tcx> {
-    global_tcx: TyCtxt<'gcx, 'gcx>,
+/// `F: for<'b, 'tcx> where 'tcx FnOnce(InferCtxt<'b, 'tcx>)`.
+pub struct InferCtxtBuilder<'tcx> {
+    global_tcx: TyCtxt<'tcx>,
     fresh_tables: Option<RefCell<ty::TypeckTables<'tcx>>>,
 }
 
-impl TyCtxt<'gcx, 'gcx> {
-    pub fn infer_ctxt<'tcx>(self) -> InferCtxtBuilder<'gcx, 'tcx> {
+impl TyCtxt<'tcx> {
+    pub fn infer_ctxt(self) -> InferCtxtBuilder<'tcx> {
         InferCtxtBuilder {
             global_tcx: self,
             fresh_tables: None,
@@ -479,7 +479,7 @@ impl TyCtxt<'gcx, 'gcx> {
     }
 }
 
-impl<'gcx, 'tcx> InferCtxtBuilder<'gcx, 'tcx> {
+impl<'tcx> InferCtxtBuilder<'tcx> {
     /// Used only by `rustc_typeck` during body type-checking/inference,
     /// will initialize `in_progress_tables` with fresh `TypeckTables`.
     pub fn with_fresh_in_progress_tables(mut self, table_owner: DefId) -> Self {
@@ -495,10 +495,10 @@ impl<'gcx, 'tcx> InferCtxtBuilder<'gcx, 'tcx> {
     /// the bound values in `C` to their instantiated values in `V`
     /// (in other words, `S(C) = V`).
     pub fn enter_with_canonical<T, R>(
-        &'tcx mut self,
+        &mut self,
         span: Span,
         canonical: &Canonical<'tcx, T>,
-        f: impl for<'a> FnOnce(InferCtxt<'a, 'gcx, 'tcx>, T, CanonicalVarValues<'tcx>) -> R,
+        f: impl for<'a> FnOnce(InferCtxt<'a, 'tcx>, T, CanonicalVarValues<'tcx>) -> R,
     ) -> R
     where
         T: TypeFoldable<'tcx>,
@@ -510,7 +510,7 @@ impl<'gcx, 'tcx> InferCtxtBuilder<'gcx, 'tcx> {
         })
     }
 
-    pub fn enter<R>(&mut self, f: impl for<'a> FnOnce(InferCtxt<'a, 'gcx, 'tcx>) -> R) -> R {
+    pub fn enter<R>(&mut self, f: impl for<'a> FnOnce(InferCtxt<'a, 'tcx>) -> R) -> R {
         let InferCtxtBuilder {
             global_tcx,
             ref fresh_tables,
@@ -567,7 +567,7 @@ impl<'tcx, T> InferOk<'tcx, T> {
     /// Extracts `value`, registering any obligations into `fulfill_cx`.
     pub fn into_value_registering_obligations(
         self,
-        infcx: &InferCtxt<'_, '_, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
         fulfill_cx: &mut dyn TraitEngine<'tcx>,
     ) -> T {
         let InferOk { value, obligations } = self;
@@ -598,7 +598,7 @@ pub struct CombinedSnapshot<'a, 'tcx: 'a> {
     _in_progress_tables: Option<Ref<'a, ty::TypeckTables<'tcx>>>,
 }
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn is_in_snapshot(&self) -> bool {
         self.in_snapshot.get()
     }
@@ -614,7 +614,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    pub fn freshener<'b>(&'b self) -> TypeFreshener<'b, 'gcx, 'tcx> {
+    pub fn freshener<'b>(&'b self) -> TypeFreshener<'b, 'tcx> {
         freshen::TypeFreshener::new(self)
     }
 
@@ -677,7 +677,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         &'a self,
         trace: TypeTrace<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
-    ) -> CombineFields<'a, 'gcx, 'tcx> {
+    ) -> CombineFields<'a, 'tcx> {
         CombineFields {
             infcx: self,
             trace,
@@ -1548,13 +1548,13 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     }
 }
 
-pub struct ShallowResolver<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+pub struct ShallowResolver<'a, 'tcx> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
 }
 
-impl<'a, 'gcx, 'tcx> ShallowResolver<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> ShallowResolver<'a, 'tcx> {
     #[inline(always)]
-    pub fn new(infcx: &'a InferCtxt<'a, 'gcx, 'tcx>) -> Self {
+    pub fn new(infcx: &'a InferCtxt<'a, 'tcx>) -> Self {
         ShallowResolver { infcx }
     }
 
@@ -1599,8 +1599,8 @@ impl<'a, 'gcx, 'tcx> ShallowResolver<'a, 'gcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for ShallowResolver<'a, 'gcx, 'tcx> {
-    fn tcx<'b>(&'b self) -> TyCtxt<'gcx, 'tcx> {
+impl<'a, 'tcx> TypeFolder<'tcx> for ShallowResolver<'a, 'tcx> {
+    fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 
@@ -1624,7 +1624,7 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for ShallowResolver<'a, 'gcx, 'tcx>
     }
 }
 
-impl<'gcx, 'tcx> TypeTrace<'tcx> {
+impl<'tcx> TypeTrace<'tcx> {
     pub fn span(&self) -> Span {
         self.cause.span
     }
@@ -1641,7 +1641,7 @@ impl<'gcx, 'tcx> TypeTrace<'tcx> {
         }
     }
 
-    pub fn dummy(tcx: TyCtxt<'gcx, 'tcx>) -> TypeTrace<'tcx> {
+    pub fn dummy(tcx: TyCtxt<'tcx>) -> TypeTrace<'tcx> {
         TypeTrace {
             cause: ObligationCause::dummy(),
             values: Types(ExpectedFound {

src/librustc/infer/nll_relate/mod.rs

@@ -38,11 +38,11 @@ pub enum NormalizationStrategy {
     Eager,
 }
 
-pub struct TypeRelating<'me, 'gcx: 'tcx, 'tcx: 'me, D>
+pub struct TypeRelating<'me, 'tcx: 'me, D>
 where
     D: TypeRelatingDelegate<'tcx>,
 {
-    infcx: &'me InferCtxt<'me, 'gcx, 'tcx>,
+    infcx: &'me InferCtxt<'me, 'tcx>,
 
     /// Callback to use when we deduce an outlives relationship
     delegate: D,
@@ -135,12 +135,12 @@ struct BoundRegionScope<'tcx> {
 #[derive(Copy, Clone)]
 struct UniversallyQuantified(bool);
 
-impl<'me, 'gcx, 'tcx, D> TypeRelating<'me, 'gcx, 'tcx, D>
+impl<'me, 'tcx, D> TypeRelating<'me, 'tcx, D>
 where
     D: TypeRelatingDelegate<'tcx>,
 {
     pub fn new(
-        infcx: &'me InferCtxt<'me, 'gcx, 'tcx>,
+        infcx: &'me InferCtxt<'me, 'tcx>,
         delegate: D,
         ambient_variance: ty::Variance,
     ) -> Self {
@@ -416,7 +416,7 @@ trait VidValuePair<'tcx>: Debug {
     /// for more details on why we want them.
     fn vid_scopes<D: TypeRelatingDelegate<'tcx>>(
         &self,
-        relate: &'r mut TypeRelating<'_, '_, 'tcx, D>,
+        relate: &'r mut TypeRelating<'_, 'tcx, D>,
     ) -> &'r mut Vec<BoundRegionScope<'tcx>>;
 
     /// Given a generalized type G that should replace the vid, relate
@@ -424,7 +424,7 @@ trait VidValuePair<'tcx>: Debug {
     /// appeared.
     fn relate_generalized_ty<D>(
         &self,
-        relate: &mut TypeRelating<'_, '_, 'tcx, D>,
+        relate: &mut TypeRelating<'_, 'tcx, D>,
         generalized_ty: Ty<'tcx>,
     ) -> RelateResult<'tcx, Ty<'tcx>>
     where
@@ -442,7 +442,7 @@ impl VidValuePair<'tcx> for (ty::TyVid, Ty<'tcx>) {
 
     fn vid_scopes<D>(
         &self,
-        relate: &'r mut TypeRelating<'_, '_, 'tcx, D>,
+        relate: &'r mut TypeRelating<'_, 'tcx, D>,
     ) -> &'r mut Vec<BoundRegionScope<'tcx>>
     where
         D: TypeRelatingDelegate<'tcx>,
@@ -452,7 +452,7 @@ impl VidValuePair<'tcx> for (ty::TyVid, Ty<'tcx>) {
 
     fn relate_generalized_ty<D>(
         &self,
-        relate: &mut TypeRelating<'_, '_, 'tcx, D>,
+        relate: &mut TypeRelating<'_, 'tcx, D>,
         generalized_ty: Ty<'tcx>,
     ) -> RelateResult<'tcx, Ty<'tcx>>
     where
@@ -474,7 +474,7 @@ impl VidValuePair<'tcx> for (Ty<'tcx>, ty::TyVid) {
 
     fn vid_scopes<D>(
         &self,
-        relate: &'r mut TypeRelating<'_, '_, 'tcx, D>,
+        relate: &'r mut TypeRelating<'_, 'tcx, D>,
     ) -> &'r mut Vec<BoundRegionScope<'tcx>>
     where
         D: TypeRelatingDelegate<'tcx>,
@@ -484,7 +484,7 @@ impl VidValuePair<'tcx> for (Ty<'tcx>, ty::TyVid) {
 
     fn relate_generalized_ty<D>(
         &self,
-        relate: &mut TypeRelating<'_, '_, 'tcx, D>,
+        relate: &mut TypeRelating<'_, 'tcx, D>,
         generalized_ty: Ty<'tcx>,
     ) -> RelateResult<'tcx, Ty<'tcx>>
     where
@@ -494,11 +494,11 @@ impl VidValuePair<'tcx> for (Ty<'tcx>, ty::TyVid) {
     }
 }
 
-impl<D> TypeRelation<'gcx, 'tcx> for TypeRelating<'me, 'gcx, 'tcx, D>
+impl<D> TypeRelation<'tcx> for TypeRelating<'me, 'tcx, D>
 where
     D: TypeRelatingDelegate<'tcx>,
 {
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 
@@ -798,11 +798,11 @@ impl<'me, 'tcx> TypeVisitor<'tcx> for ScopeInstantiator<'me, 'tcx> {
 /// scopes.
 ///
 /// [blog post]: https://is.gd/0hKvIr
-struct TypeGeneralizer<'me, 'gcx: 'tcx, 'tcx: 'me, D>
+struct TypeGeneralizer<'me, 'tcx: 'me, D>
 where
     D: TypeRelatingDelegate<'tcx> + 'me,
 {
-    infcx: &'me InferCtxt<'me, 'gcx, 'tcx>,
+    infcx: &'me InferCtxt<'me, 'tcx>,
 
     delegate: &'me mut D,
 
@@ -823,11 +823,11 @@ where
     universe: ty::UniverseIndex,
 }
 
-impl<D> TypeRelation<'gcx, 'tcx> for TypeGeneralizer<'me, 'gcx, 'tcx, D>
+impl<D> TypeRelation<'tcx> for TypeGeneralizer<'me, 'tcx, D>
 where
     D: TypeRelatingDelegate<'tcx>,
 {
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 

src/librustc/infer/opaque_types/mod.rs

@@ -73,7 +73,7 @@ pub struct OpaqueTypeDecl<'tcx> {
     pub origin: hir::ExistTyOrigin,
 }
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     /// Replaces all opaque types in `value` with fresh inference variables
     /// and creates appropriate obligations. For example, given the input:
     ///
@@ -430,8 +430,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         &self,
         def_id: DefId,
         opaque_defn: &OpaqueTypeDecl<'tcx>,
-        instantiated_ty: Ty<'gcx>,
-    ) -> Ty<'gcx> {
+        instantiated_ty: Ty<'tcx>,
+    ) -> Ty<'tcx> {
         debug!(
             "infer_opaque_definition_from_instantiation(def_id={:?}, instantiated_ty={:?})",
             def_id, instantiated_ty
@@ -446,7 +446,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         // `impl Trait` return type, resulting in the parameters
         // shifting.
         let id_substs = InternalSubsts::identity_for_item(gcx, def_id);
-        let map: FxHashMap<Kind<'tcx>, Kind<'gcx>> = opaque_defn
+        let map: FxHashMap<Kind<'tcx>, Kind<'tcx>> = opaque_defn
             .substs
             .iter()
             .enumerate()
@@ -470,7 +470,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         );
 
         // We can unwrap here because our reverse mapper always
-        // produces things with 'gcx lifetime, though the type folder
+        // produces things with 'tcx lifetime, though the type folder
         // obscures that.
         let definition_ty = gcx.lift(&definition_ty).unwrap();
 
@@ -491,14 +491,13 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
 //
 // We ignore any type parameters because impl trait values are assumed to
 // capture all the in-scope type parameters.
-struct OpaqueTypeOutlivesVisitor<'a, 'gcx, 'tcx> {
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+struct OpaqueTypeOutlivesVisitor<'a, 'tcx> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
     least_region: ty::Region<'tcx>,
     span: Span,
 }
 
-impl<'tcx> TypeVisitor<'tcx> for OpaqueTypeOutlivesVisitor<'_, '_, 'tcx>
-{
+impl<'tcx> TypeVisitor<'tcx> for OpaqueTypeOutlivesVisitor<'_, 'tcx> {
     fn visit_binder<T: TypeFoldable<'tcx>>(&mut self, t: &ty::Binder<T>) -> bool {
         t.skip_binder().visit_with(self);
         false // keep visiting
@@ -552,27 +551,27 @@ impl<'tcx> TypeVisitor<'tcx> for OpaqueTypeOutlivesVisitor<'_, '_, 'tcx>
     }
 }
 
-struct ReverseMapper<'gcx, 'tcx> {
-    tcx: TyCtxt<'gcx, 'tcx>,
+struct ReverseMapper<'tcx> {
+    tcx: TyCtxt<'tcx>,
 
     /// If errors have already been reported in this fn, we suppress
     /// our own errors because they are sometimes derivative.
     tainted_by_errors: bool,
 
     opaque_type_def_id: DefId,
-    map: FxHashMap<Kind<'tcx>, Kind<'gcx>>,
+    map: FxHashMap<Kind<'tcx>, Kind<'tcx>>,
     map_missing_regions_to_empty: bool,
 
     /// initially `Some`, set to `None` once error has been reported
     hidden_ty: Option<Ty<'tcx>>,
 }
 
-impl ReverseMapper<'gcx, 'tcx> {
+impl ReverseMapper<'tcx> {
     fn new(
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         tainted_by_errors: bool,
         opaque_type_def_id: DefId,
-        map: FxHashMap<Kind<'tcx>, Kind<'gcx>>,
+        map: FxHashMap<Kind<'tcx>, Kind<'tcx>>,
         hidden_ty: Ty<'tcx>,
     ) -> Self {
         Self {
@@ -599,8 +598,8 @@ impl ReverseMapper<'gcx, 'tcx> {
     }
 }
 
-impl TypeFolder<'gcx, 'tcx> for ReverseMapper<'gcx, 'tcx> {
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> {
+impl TypeFolder<'tcx> for ReverseMapper<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
 
@@ -724,8 +723,8 @@ impl TypeFolder<'gcx, 'tcx> for ReverseMapper<'gcx, 'tcx> {
     }
 }
 
-struct Instantiator<'a, 'gcx: 'tcx, 'tcx: 'a> {
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+struct Instantiator<'a, 'tcx: 'a> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
     parent_def_id: DefId,
     body_id: hir::HirId,
     param_env: ty::ParamEnv<'tcx>,
@@ -733,7 +732,7 @@ struct Instantiator<'a, 'gcx: 'tcx, 'tcx: 'a> {
     obligations: Vec<PredicateObligation<'tcx>>,
 }
 
-impl<'a, 'gcx, 'tcx> Instantiator<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> Instantiator<'a, 'tcx> {
     fn instantiate_opaque_types_in_map<T: TypeFoldable<'tcx>>(&mut self, value: &T) -> T {
         debug!("instantiate_opaque_types_in_map(value={:?})", value);
         let tcx = self.infcx.tcx;
@@ -944,7 +943,7 @@ impl<'a, 'gcx, 'tcx> Instantiator<'a, 'gcx, 'tcx> {
 /// and `opaque_hir_id` is the `HirId` of the definition of the existential type `Baz`.
 /// For the above example, this function returns `true` for `f1` and `false` for `f2`.
 pub fn may_define_existential_type(
-    tcx: TyCtxt<'_, '_>,
+    tcx: TyCtxt<'_>,
     def_id: DefId,
     opaque_hir_id: hir::HirId,
 ) -> bool {

src/librustc/infer/outlives/env.rs

@@ -67,7 +67,7 @@ pub struct OutlivesEnvironment<'tcx> {
 /// because of implied bounds.
 pub type RegionBoundPairs<'tcx> = Vec<(ty::Region<'tcx>, GenericKind<'tcx>)>;
 
-impl<'a, 'gcx: 'tcx, 'tcx: 'a> OutlivesEnvironment<'tcx> {
+impl<'a, 'tcx: 'a> OutlivesEnvironment<'tcx> {
     pub fn new(param_env: ty::ParamEnv<'tcx>) -> Self {
         let mut env = OutlivesEnvironment {
             param_env,
@@ -160,7 +160,7 @@ impl<'a, 'gcx: 'tcx, 'tcx: 'a> OutlivesEnvironment<'tcx> {
     /// Tests: `src/test/compile-fail/regions-free-region-ordering-*.rs`
     pub fn add_implied_bounds(
         &mut self,
-        infcx: &InferCtxt<'a, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'a, 'tcx>,
         fn_sig_tys: &[Ty<'tcx>],
         body_id: hir::HirId,
         span: Span,
@@ -192,7 +192,7 @@ impl<'a, 'gcx: 'tcx, 'tcx: 'a> OutlivesEnvironment<'tcx> {
     /// `RegionConstraintData`.)
     fn add_outlives_bounds<I>(
         &mut self,
-        infcx: Option<&InferCtxt<'a, 'gcx, 'tcx>>,
+        infcx: Option<&InferCtxt<'a, 'tcx>>,
         outlives_bounds: I,
     ) where
         I: IntoIterator<Item = OutlivesBound<'tcx>>,

src/librustc/infer/outlives/free_region_map.rs

@@ -28,9 +28,9 @@ impl<'tcx> FreeRegionMap<'tcx> {
     /// cases, this is more conservative than necessary, in order to
     /// avoid making arbitrary choices. See
     /// `TransitiveRelation::postdom_upper_bound` for more details.
-    pub fn lub_free_regions<'gcx>(
+    pub fn lub_free_regions(
         &self,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         r_a: Region<'tcx>,
         r_b: Region<'tcx>,
     ) -> Region<'tcx> {
@@ -91,7 +91,7 @@ impl_stable_hash_for!(struct FreeRegionMap<'tcx> {
 
 impl<'a, 'tcx> Lift<'tcx> for FreeRegionMap<'a> {
     type Lifted = FreeRegionMap<'tcx>;
-    fn lift_to_tcx<'gcx>(&self, tcx: TyCtxt<'gcx, 'tcx>) -> Option<FreeRegionMap<'tcx>> {
+    fn lift_to_tcx(&self, tcx: TyCtxt<'tcx>) -> Option<FreeRegionMap<'tcx>> {
         self.relation.maybe_map(|&fr| tcx.lift(&fr))
                      .map(|relation| FreeRegionMap { relation })
     }

src/librustc/infer/outlives/obligations.rs

@@ -69,7 +69,7 @@ use crate::ty::outlives::Component;
 use crate::ty::{self, Region, Ty, TyCtxt, TypeFoldable};
 use crate::ty::subst::UnpackedKind;
 
-impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// Registers that the given region obligation must be resolved
     /// from within the scope of `body_id`. These regions are enqueued
     /// and later processed by regionck, when full type information is
@@ -226,15 +226,15 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
 /// via a "delegate" of type `D` -- this is usually the `infcx`, which
 /// accrues them into the `region_obligations` code, but for NLL we
 /// use something else.
-pub struct TypeOutlives<'cx, 'gcx: 'tcx, 'tcx: 'cx, D>
+pub struct TypeOutlives<'cx, 'tcx: 'cx, D>
 where
     D: TypeOutlivesDelegate<'tcx>,
 {
     // See the comments on `process_registered_region_obligations` for the meaning
     // of these fields.
     delegate: D,
-    tcx: TyCtxt<'gcx, 'tcx>,
-    verify_bound: VerifyBoundCx<'cx, 'gcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
+    verify_bound: VerifyBoundCx<'cx, 'tcx>,
 }
 
 pub trait TypeOutlivesDelegate<'tcx> {
@@ -254,13 +254,13 @@ pub trait TypeOutlivesDelegate<'tcx> {
     );
 }
 
-impl<'cx, 'gcx, 'tcx, D> TypeOutlives<'cx, 'gcx, 'tcx, D>
+impl<'cx, 'tcx, D> TypeOutlives<'cx, 'tcx, D>
 where
     D: TypeOutlivesDelegate<'tcx>,
 {
     pub fn new(
         delegate: D,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         region_bound_pairs: &'cx RegionBoundPairs<'tcx>,
         implicit_region_bound: Option<ty::Region<'tcx>>,
         param_env: ty::ParamEnv<'tcx>,
@@ -487,7 +487,7 @@ where
     }
 }
 
-impl<'cx, 'gcx, 'tcx> TypeOutlivesDelegate<'tcx> for &'cx InferCtxt<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> TypeOutlivesDelegate<'tcx> for &'cx InferCtxt<'cx, 'tcx> {
     fn push_sub_region_constraint(
         &mut self,
         origin: SubregionOrigin<'tcx>,

src/librustc/infer/outlives/verify.rs

@@ -12,16 +12,16 @@ use crate::util::captures::Captures;
 /// via a "delegate" of type `D` -- this is usually the `infcx`, which
 /// accrues them into the `region_obligations` code, but for NLL we
 /// use something else.
-pub struct VerifyBoundCx<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
-    tcx: TyCtxt<'gcx, 'tcx>,
+pub struct VerifyBoundCx<'cx, 'tcx: 'cx> {
+    tcx: TyCtxt<'tcx>,
     region_bound_pairs: &'cx RegionBoundPairs<'tcx>,
     implicit_region_bound: Option<ty::Region<'tcx>>,
     param_env: ty::ParamEnv<'tcx>,
 }
 
-impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
     pub fn new(
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         region_bound_pairs: &'cx RegionBoundPairs<'tcx>,
         implicit_region_bound: Option<ty::Region<'tcx>>,
         param_env: ty::ParamEnv<'tcx>,
@@ -102,7 +102,7 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
     pub fn projection_declared_bounds_from_trait(
         &self,
         projection_ty: ty::ProjectionTy<'tcx>,
-    ) -> impl Iterator<Item = ty::Region<'tcx>> + 'cx + Captures<'gcx> {
+    ) -> impl Iterator<Item = ty::Region<'tcx>> + 'cx + Captures<'tcx> {
         self.declared_projection_bounds_from_trait(projection_ty)
     }
 
@@ -244,7 +244,7 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
     fn declared_projection_bounds_from_trait(
         &self,
         projection_ty: ty::ProjectionTy<'tcx>,
-    ) -> impl Iterator<Item = ty::Region<'tcx>> + 'cx + Captures<'gcx> {
+    ) -> impl Iterator<Item = ty::Region<'tcx>> + 'cx + Captures<'tcx> {
         debug!("projection_bounds(projection_ty={:?})", projection_ty);
         let tcx = self.tcx;
         self.region_bounds_declared_on_associated_item(projection_ty.item_def_id)
@@ -284,7 +284,7 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
     fn region_bounds_declared_on_associated_item(
         &self,
         assoc_item_def_id: DefId,
-    ) -> impl Iterator<Item = ty::Region<'tcx>> + 'cx + Captures<'gcx> {
+    ) -> impl Iterator<Item = ty::Region<'tcx>> + 'cx + Captures<'tcx> {
         let tcx = self.tcx;
         let assoc_item = tcx.associated_item(assoc_item_def_id);
         let trait_def_id = assoc_item.container.assert_trait();

src/librustc/infer/region_constraints/leak_check.rs

@@ -22,7 +22,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
     /// refactor the constraint set.
     pub fn leak_check(
         &mut self,
-        tcx: TyCtxt<'_, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         overly_polymorphic: bool,
         placeholder_map: &PlaceholderMap<'tcx>,
         _snapshot: &CombinedSnapshot<'_, 'tcx>,
@@ -109,7 +109,7 @@ impl<'tcx> TaintSet<'tcx> {
 
     fn fixed_point(
         &mut self,
-        tcx: TyCtxt<'_, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         undo_log: &[UndoLog<'tcx>],
         verifys: &[Verify<'tcx>],
     ) {

src/librustc/infer/region_constraints/mod.rs

@@ -700,7 +700,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
 
     pub fn lub_regions(
         &mut self,
-        tcx: TyCtxt<'_, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         origin: SubregionOrigin<'tcx>,
         a: Region<'tcx>,
         b: Region<'tcx>,
@@ -722,7 +722,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
 
     pub fn glb_regions(
         &mut self,
-        tcx: TyCtxt<'_, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         origin: SubregionOrigin<'tcx>,
         a: Region<'tcx>,
         b: Region<'tcx>,
@@ -744,7 +744,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
 
     pub fn opportunistic_resolve_var(
         &mut self,
-        tcx: TyCtxt<'_, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         rid: RegionVid,
     ) -> ty::Region<'tcx> {
         let vid = self.unification_table.probe_value(rid).min_vid;
@@ -760,7 +760,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
 
     fn combine_vars(
         &mut self,
-        tcx: TyCtxt<'_, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         t: CombineMapType,
         a: Region<'tcx>,
         b: Region<'tcx>,
@@ -849,8 +849,8 @@ impl<'tcx> fmt::Display for GenericKind<'tcx> {
     }
 }
 
-impl<'gcx, 'tcx> GenericKind<'tcx> {
-    pub fn to_ty(&self, tcx: TyCtxt<'gcx, 'tcx>) -> Ty<'tcx> {
+impl<'tcx> GenericKind<'tcx> {
+    pub fn to_ty(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
         match *self {
             GenericKind::Param(ref p) => p.to_ty(tcx),
             GenericKind::Projection(ref p) => tcx.mk_projection(p.item_def_id, p.substs),

src/librustc/infer/resolve.rs

@@ -12,19 +12,19 @@ use crate::ty::fold::{TypeFolder, TypeVisitor};
 /// been unified with (similar to `shallow_resolve`, but deep). This is
 /// useful for printing messages etc but also required at various
 /// points for correctness.
-pub struct OpportunisticVarResolver<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+pub struct OpportunisticVarResolver<'a, 'tcx: 'a> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
 }
 
-impl<'a, 'gcx, 'tcx> OpportunisticVarResolver<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> OpportunisticVarResolver<'a, 'tcx> {
     #[inline]
-    pub fn new(infcx: &'a InferCtxt<'a, 'gcx, 'tcx>) -> Self {
+    pub fn new(infcx: &'a InferCtxt<'a, 'tcx>) -> Self {
         OpportunisticVarResolver { infcx }
     }
 }
 
-impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for OpportunisticVarResolver<'a, 'gcx, 'tcx> {
-    fn tcx<'b>(&'b self) -> TyCtxt<'gcx, 'tcx> {
+impl<'a, 'tcx> TypeFolder<'tcx> for OpportunisticVarResolver<'a, 'tcx> {
+    fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 
@@ -50,18 +50,18 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for OpportunisticVarResolver<'a, 'gc
 /// The opportunistic type and region resolver is similar to the
 /// opportunistic type resolver, but also opportunistically resolves
 /// regions. It is useful for canonicalization.
-pub struct OpportunisticTypeAndRegionResolver<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+pub struct OpportunisticTypeAndRegionResolver<'a, 'tcx: 'a> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
 }
 
-impl<'a, 'gcx, 'tcx> OpportunisticTypeAndRegionResolver<'a, 'gcx, 'tcx> {
-    pub fn new(infcx: &'a InferCtxt<'a, 'gcx, 'tcx>) -> Self {
+impl<'a, 'tcx> OpportunisticTypeAndRegionResolver<'a, 'tcx> {
+    pub fn new(infcx: &'a InferCtxt<'a, 'tcx>) -> Self {
         OpportunisticTypeAndRegionResolver { infcx }
     }
 }
 
-impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for OpportunisticTypeAndRegionResolver<'a, 'gcx, 'tcx> {
-    fn tcx<'b>(&'b self) -> TyCtxt<'gcx, 'tcx> {
+impl<'a, 'tcx> TypeFolder<'tcx> for OpportunisticTypeAndRegionResolver<'a, 'tcx> {
+    fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 
@@ -101,20 +101,20 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for OpportunisticTypeAndRegionResolv
 /// type variables that don't yet have a value. The first unresolved type is stored.
 /// It does not construct the fully resolved type (which might
 /// involve some hashing and so forth).
-pub struct UnresolvedTypeFinder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+pub struct UnresolvedTypeFinder<'a, 'tcx: 'a> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
 
     /// Used to find the type parameter name and location for error reporting.
     pub first_unresolved: Option<(Ty<'tcx>,Option<Span>)>,
 }
 
-impl<'a, 'gcx, 'tcx> UnresolvedTypeFinder<'a, 'gcx, 'tcx> {
-    pub fn new(infcx: &'a InferCtxt<'a, 'gcx, 'tcx>) -> Self {
+impl<'a, 'tcx> UnresolvedTypeFinder<'a, 'tcx> {
+    pub fn new(infcx: &'a InferCtxt<'a, 'tcx>) -> Self {
         UnresolvedTypeFinder { infcx, first_unresolved: None }
     }
 }
 
-impl<'a, 'gcx, 'tcx> TypeVisitor<'tcx> for UnresolvedTypeFinder<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> TypeVisitor<'tcx> for UnresolvedTypeFinder<'a, 'tcx> {
     fn visit_ty(&mut self, t: Ty<'tcx>) -> bool {
         let t = self.infcx.shallow_resolve(t);
         if t.has_infer_types() {
@@ -157,7 +157,7 @@ impl<'a, 'gcx, 'tcx> TypeVisitor<'tcx> for UnresolvedTypeFinder<'a, 'gcx, 'tcx>
 /// Full type resolution replaces all type and region variables with
 /// their concrete results. If any variable cannot be replaced (never unified, etc)
 /// then an `Err` result is returned.
-pub fn fully_resolve<'a, 'gcx, 'tcx, T>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
+pub fn fully_resolve<'a, 'tcx, T>(infcx: &InferCtxt<'a, 'tcx>,
                                         value: &T) -> FixupResult<'tcx, T>
     where T : TypeFoldable<'tcx>
 {
@@ -171,13 +171,13 @@ pub fn fully_resolve<'a, 'gcx, 'tcx, T>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
 
 // N.B. This type is not public because the protocol around checking the
 // `err` field is not enforcable otherwise.
-struct FullTypeResolver<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+struct FullTypeResolver<'a, 'tcx: 'a> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
     err: Option<FixupError<'tcx>>,
 }
 
-impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for FullTypeResolver<'a, 'gcx, 'tcx> {
-    fn tcx<'b>(&'b self) -> TyCtxt<'gcx, 'tcx> {
+impl<'a, 'tcx> TypeFolder<'tcx> for FullTypeResolver<'a, 'tcx> {
+    fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 

src/librustc/infer/sub.rs

@@ -11,14 +11,14 @@ use crate::mir::interpret::ConstValue;
 use std::mem;
 
 /// Ensures `a` is made a subtype of `b`. Returns `a` on success.
-pub struct Sub<'combine, 'infcx: 'combine, 'gcx: 'infcx+'tcx, 'tcx: 'infcx> {
-    fields: &'combine mut CombineFields<'infcx, 'gcx, 'tcx>,
+pub struct Sub<'combine, 'infcx: 'combine, 'tcx: 'infcx> {
+    fields: &'combine mut CombineFields<'infcx, 'tcx>,
     a_is_expected: bool,
 }
 
-impl<'combine, 'infcx, 'gcx, 'tcx> Sub<'combine, 'infcx, 'gcx, 'tcx> {
-    pub fn new(f: &'combine mut CombineFields<'infcx, 'gcx, 'tcx>, a_is_expected: bool)
-        -> Sub<'combine, 'infcx, 'gcx, 'tcx>
+impl<'combine, 'infcx, 'tcx> Sub<'combine, 'infcx, 'tcx> {
+    pub fn new(f: &'combine mut CombineFields<'infcx, 'tcx>, a_is_expected: bool)
+        -> Sub<'combine, 'infcx, 'tcx>
     {
         Sub { fields: f, a_is_expected: a_is_expected }
     }
@@ -31,9 +31,9 @@ impl<'combine, 'infcx, 'gcx, 'tcx> Sub<'combine, 'infcx, 'gcx, 'tcx> {
     }
 }
 
-impl TypeRelation<'gcx, 'tcx> for Sub<'combine, 'infcx, 'gcx, 'tcx> {
+impl TypeRelation<'tcx> for Sub<'combine, 'infcx, 'tcx> {
     fn tag(&self) -> &'static str { "Sub" }
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> { self.fields.infcx.tcx }
+    fn tcx(&self) -> TyCtxt<'tcx> { self.fields.infcx.tcx }
     fn a_is_expected(&self) -> bool { self.a_is_expected }
 
     fn with_cause<F,R>(&mut self, cause: Cause, f: F) -> R

src/librustc/infer/unify_key.rs

@@ -10,7 +10,7 @@ use std::marker::PhantomData;
 use std::cell::RefMut;
 
 pub trait ToType {
-    fn to_type<'gcx, 'tcx>(&self, tcx: TyCtxt<'gcx, 'tcx>) -> Ty<'tcx>;
+    fn to_type<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx>;
 }
 
 impl UnifyKey for ty::IntVid {
@@ -52,7 +52,7 @@ impl UnifyKey for ty::RegionVid {
 }
 
 impl ToType for IntVarValue {
-    fn to_type<'gcx, 'tcx>(&self, tcx: TyCtxt<'gcx, 'tcx>) -> Ty<'tcx> {
+    fn to_type<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
         match *self {
             ty::IntType(i) => tcx.mk_mach_int(i),
             ty::UintType(i) => tcx.mk_mach_uint(i),
@@ -72,7 +72,7 @@ impl UnifyKey for ty::FloatVid {
 impl EqUnifyValue for FloatVarValue {}
 
 impl ToType for FloatVarValue {
-    fn to_type<'gcx, 'tcx>(&self, tcx: TyCtxt<'gcx, 'tcx>) -> Ty<'tcx> {
+    fn to_type<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
         tcx.mk_mach_float(self.0)
     }
 }

src/librustc/lint/context.rs

@@ -509,7 +509,7 @@ impl LintStore {
 /// Context for lint checking after type checking.
 pub struct LateContext<'a, 'tcx: 'a> {
     /// Type context we're checking in.
-    pub tcx: TyCtxt<'tcx, 'tcx>,
+    pub tcx: TyCtxt<'tcx>,
 
     /// Side-tables for the body we are in.
     // FIXME: Make this lazy to avoid running the TypeckTables query?
@@ -781,10 +781,10 @@ impl<'a, 'tcx> LateContext<'a, 'tcx> {
     /// ```
     pub fn get_def_path(&self, def_id: DefId) -> Vec<Symbol> {
         pub struct AbsolutePathPrinter<'tcx> {
-            pub tcx: TyCtxt<'tcx, 'tcx>,
+            pub tcx: TyCtxt<'tcx>,
         }
 
-        impl<'tcx> Printer<'tcx, 'tcx> for AbsolutePathPrinter<'tcx> {
+        impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
             type Error = !;
 
             type Path = Vec<Symbol>;
@@ -793,7 +793,7 @@ impl<'a, 'tcx> LateContext<'a, 'tcx> {
             type DynExistential = ();
             type Const = ();
 
-            fn tcx(&self) -> TyCtxt<'tcx, 'tcx> {
+            fn tcx(&self) -> TyCtxt<'tcx> {
                 self.tcx
             }
 
@@ -1372,7 +1372,7 @@ macro_rules! late_lint_pass_impl {
 late_lint_methods!(late_lint_pass_impl, [], ['tcx]);
 
 fn late_lint_mod_pass<'tcx, T: for<'a> LateLintPass<'a, 'tcx>>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     module_def_id: DefId,
     pass: T,
 ) {
@@ -1404,7 +1404,7 @@ fn late_lint_mod_pass<'tcx, T: for<'a> LateLintPass<'a, 'tcx>>(
 }
 
 pub fn late_lint_mod<'tcx, T: for<'a> LateLintPass<'a, 'tcx>>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     module_def_id: DefId,
     builtin_lints: T,
 ) {
@@ -1423,7 +1423,7 @@ pub fn late_lint_mod<'tcx, T: for<'a> LateLintPass<'a, 'tcx>>(
     }
 }
 
-fn late_lint_pass_crate<'tcx, T: for<'a> LateLintPass<'a, 'tcx>>(tcx: TyCtxt<'tcx, 'tcx>, pass: T) {
+fn late_lint_pass_crate<'tcx, T: for<'a> LateLintPass<'a, 'tcx>>(tcx: TyCtxt<'tcx>, pass: T) {
     let access_levels = &tcx.privacy_access_levels(LOCAL_CRATE);
 
     let krate = tcx.hir().krate();
@@ -1457,7 +1457,7 @@ fn late_lint_pass_crate<'tcx, T: for<'a> LateLintPass<'a, 'tcx>>(tcx: TyCtxt<'tc
 }
 
 fn late_lint_crate<'tcx, T: for<'a> LateLintPass<'a, 'tcx>>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     builtin_lints: T,
 ) {
     let mut passes = tcx.sess.lint_store.borrow().late_passes.lock().take().unwrap();
@@ -1491,7 +1491,7 @@ fn late_lint_crate<'tcx, T: for<'a> LateLintPass<'a, 'tcx>>(
 
 /// Performs lint checking on a crate.
 pub fn check_crate<'tcx, T: for<'a> LateLintPass<'a, 'tcx>>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     builtin_lints: impl FnOnce() -> T + Send,
 ) {
     join(|| {

src/librustc/lint/mod.rs

@@ -761,12 +761,12 @@ pub fn struct_lint_level<'a>(sess: &'a Session,
     return err
 }
 
-pub fn maybe_lint_level_root(tcx: TyCtxt<'_, '_>, id: hir::HirId) -> bool {
+pub fn maybe_lint_level_root(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
     let attrs = tcx.hir().attrs_by_hir_id(id);
     attrs.iter().any(|attr| Level::from_symbol(attr.name_or_empty()).is_some())
 }
 
-fn lint_levels<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, cnum: CrateNum) -> &'tcx LintLevelMap {
+fn lint_levels<'tcx>(tcx: TyCtxt<'tcx>, cnum: CrateNum) -> &'tcx LintLevelMap {
     assert_eq!(cnum, LOCAL_CRATE);
     let mut builder = LintLevelMapBuilder {
         levels: LintLevelSets::builder(tcx.sess),
@@ -787,7 +787,7 @@ fn lint_levels<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, cnum: CrateNum) -> &'tcx LintLevel
 
 struct LintLevelMapBuilder<'tcx> {
     levels: levels::LintLevelsBuilder<'tcx>,
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
 }
 
 impl LintLevelMapBuilder<'tcx> {

src/librustc/macros.rs

@@ -195,7 +195,7 @@ macro_rules! CloneLiftImpls {
         $(
             impl<$tcx> $crate::ty::Lift<$tcx> for $ty {
                 type Lifted = Self;
-                fn lift_to_tcx<'gcx>(&self, _: $crate::ty::TyCtxt<'gcx, $tcx>) -> Option<Self> {
+                fn lift_to_tcx(&self, _: $crate::ty::TyCtxt<$tcx>) -> Option<Self> {
                     Some(Clone::clone(self))
                 }
             }
@@ -218,7 +218,7 @@ macro_rules! CloneTypeFoldableImpls {
     (for <$tcx:lifetime> { $($ty:ty,)+ }) => {
         $(
             impl<$tcx> $crate::ty::fold::TypeFoldable<$tcx> for $ty {
-                fn super_fold_with<'gcx: $tcx, F: $crate::ty::fold::TypeFolder<'gcx, $tcx>>(
+                fn super_fold_with<F: $crate::ty::fold::TypeFolder<$tcx>>(
                     &self,
                     _: &mut F
                 ) -> $ty {
@@ -264,7 +264,7 @@ macro_rules! BraceStructLiftImpl {
         {
             type Lifted = $lifted;
 
-            fn lift_to_tcx<'gcx>(&self, tcx: TyCtxt<'gcx, 'tcx>) -> Option<$lifted> {
+            fn lift_to_tcx(&self, tcx: TyCtxt<$tcx>) -> Option<$lifted> {
                 $(let $field = tcx.lift(&self.$field)?;)*
                 Some(Self::Lifted { $($field),* })
             }
@@ -283,7 +283,7 @@ macro_rules! EnumLiftImpl {
         {
             type Lifted = $lifted;
 
-            fn lift_to_tcx<'gcx>(&self, tcx: TyCtxt<'gcx, 'tcx>) -> Option<$lifted> {
+            fn lift_to_tcx(&self, tcx: TyCtxt<$tcx>) -> Option<$lifted> {
                 EnumLiftImpl!(@Variants(self, tcx) input($($variants)*) output())
             }
         }
@@ -332,7 +332,7 @@ macro_rules! BraceStructTypeFoldableImpl {
         impl<$($p),*> $crate::ty::fold::TypeFoldable<$tcx> for $s
             $(where $($wc)*)*
         {
-            fn super_fold_with<'gcx: $tcx, V: $crate::ty::fold::TypeFolder<'gcx, $tcx>>(
+            fn super_fold_with<V: $crate::ty::fold::TypeFolder<$tcx>>(
                 &self,
                 folder: &mut V,
             ) -> Self {
@@ -359,7 +359,7 @@ macro_rules! TupleStructTypeFoldableImpl {
         impl<$($p),*> $crate::ty::fold::TypeFoldable<$tcx> for $s
             $(where $($wc)*)*
         {
-            fn super_fold_with<'gcx: $tcx, V: $crate::ty::fold::TypeFolder<'gcx, $tcx>>(
+            fn super_fold_with<V: $crate::ty::fold::TypeFolder<$tcx>>(
                 &self,
                 folder: &mut V,
             ) -> Self {
@@ -386,7 +386,7 @@ macro_rules! EnumTypeFoldableImpl {
         impl<$($p),*> $crate::ty::fold::TypeFoldable<$tcx> for $s
             $(where $($wc)*)*
         {
-            fn super_fold_with<'gcx: $tcx, V: $crate::ty::fold::TypeFolder<'gcx, $tcx>>(
+            fn super_fold_with<V: $crate::ty::fold::TypeFolder<$tcx>>(
                 &self,
                 folder: &mut V,
             ) -> Self {

src/librustc/middle/cstore.rs

@@ -211,7 +211,7 @@ pub trait CrateStore {
     fn crates_untracked(&self) -> Vec<CrateNum>;
 
     // utility functions
-    fn encode_metadata<'tcx>(&self, tcx: TyCtxt<'tcx, 'tcx>) -> EncodedMetadata;
+    fn encode_metadata<'tcx>(&self, tcx: TyCtxt<'tcx>) -> EncodedMetadata;
     fn metadata_encoding_version(&self) -> &[u8];
 }
 
@@ -226,7 +226,7 @@ pub type CrateStoreDyn = dyn CrateStore + sync::Sync;
 // In order to get this left-to-right dependency ordering, we perform a
 // topological sort of all crates putting the leaves at the right-most
 // positions.
-pub fn used_crates(tcx: TyCtxt<'_, '_>, prefer: LinkagePreference) -> Vec<(CrateNum, LibSource)> {
+pub fn used_crates(tcx: TyCtxt<'_>, prefer: LinkagePreference) -> Vec<(CrateNum, LibSource)> {
     let mut libs = tcx.crates()
         .iter()
         .cloned()

src/librustc/middle/dead.rs

@@ -26,7 +26,7 @@ use syntax_pos;
 // explored. For example, if it's a live Node::Item that is a
 // function, then we should explore its block to check for codes that
 // may need to be marked as live.
-fn should_explore<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, hir_id: hir::HirId) -> bool {
+fn should_explore<'tcx>(tcx: TyCtxt<'tcx>, hir_id: hir::HirId) -> bool {
     match tcx.hir().find_by_hir_id(hir_id) {
         Some(Node::Item(..)) |
         Some(Node::ImplItem(..)) |
@@ -40,7 +40,7 @@ fn should_explore<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, hir_id: hir::HirId) -> bool {
 
 struct MarkSymbolVisitor<'a, 'tcx: 'a> {
     worklist: Vec<hir::HirId>,
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     tables: &'a ty::TypeckTables<'tcx>,
     live_symbols: FxHashSet<hir::HirId>,
     repr_has_repr_c: bool,
@@ -302,7 +302,7 @@ impl<'a, 'tcx> Visitor<'tcx> for MarkSymbolVisitor<'a, 'tcx> {
 }
 
 fn has_allow_dead_code_or_lang_attr(
-    tcx: TyCtxt<'_, '_>,
+    tcx: TyCtxt<'_>,
     id: hir::HirId,
     attrs: &[ast::Attribute],
 ) -> bool {
@@ -354,7 +354,7 @@ fn has_allow_dead_code_or_lang_attr(
 struct LifeSeeder<'k, 'tcx: 'k> {
     worklist: Vec<hir::HirId>,
     krate: &'k hir::Crate,
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     // see `MarkSymbolVisitor::struct_constructors`
     struct_constructors: FxHashMap<hir::HirId, hir::HirId>,
 }
@@ -425,7 +425,7 @@ impl<'v, 'k, 'tcx> ItemLikeVisitor<'v> for LifeSeeder<'k, 'tcx> {
 }
 
 fn create_and_seed_worklist<'tcx>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     access_levels: &privacy::AccessLevels,
     krate: &hir::Crate,
 ) -> (Vec<hir::HirId>, FxHashMap<hir::HirId, hir::HirId>) {
@@ -453,7 +453,7 @@ fn create_and_seed_worklist<'tcx>(
 }
 
 fn find_live<'tcx>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     access_levels: &privacy::AccessLevels,
     krate: &hir::Crate,
 ) -> FxHashSet<hir::HirId> {
@@ -474,7 +474,7 @@ fn find_live<'tcx>(
 }
 
 struct DeadVisitor<'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     live_symbols: FxHashSet<hir::HirId>,
 }
 
@@ -662,7 +662,7 @@ impl Visitor<'tcx> for DeadVisitor<'tcx> {
     }
 }
 
-pub fn check_crate<'tcx>(tcx: TyCtxt<'tcx, 'tcx>) {
+pub fn check_crate<'tcx>(tcx: TyCtxt<'tcx>) {
     let access_levels = &tcx.privacy_access_levels(LOCAL_CRATE);
     let krate = tcx.hir().krate();
     let live_symbols = find_live(tcx, access_levels, krate);

src/librustc/middle/dependency_format.rs

@@ -81,7 +81,7 @@ pub enum Linkage {
     Dynamic,
 }
 
-pub fn calculate<'tcx>(tcx: TyCtxt<'tcx, 'tcx>) {
+pub fn calculate<'tcx>(tcx: TyCtxt<'tcx>) {
     let sess = &tcx.sess;
     let fmts = sess.crate_types.borrow().iter().map(|&ty| {
         let linkage = calculate_type(tcx, ty);
@@ -92,7 +92,7 @@ pub fn calculate<'tcx>(tcx: TyCtxt<'tcx, 'tcx>) {
     sess.dependency_formats.set(fmts);
 }
 
-fn calculate_type<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, ty: config::CrateType) -> DependencyList {
+fn calculate_type<'tcx>(tcx: TyCtxt<'tcx>, ty: config::CrateType) -> DependencyList {
     let sess = &tcx.sess;
 
     if !sess.opts.output_types.should_codegen() {
@@ -241,7 +241,7 @@ fn calculate_type<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, ty: config::CrateType) -> Depen
 }
 
 fn add_library(
-    tcx: TyCtxt<'_, '_>,
+    tcx: TyCtxt<'_>,
     cnum: CrateNum,
     link: LinkagePreference,
     m: &mut FxHashMap<CrateNum, LinkagePreference>,
@@ -267,7 +267,7 @@ fn add_library(
     }
 }
 
-fn attempt_static<'tcx>(tcx: TyCtxt<'tcx, 'tcx>) -> Option<DependencyList> {
+fn attempt_static<'tcx>(tcx: TyCtxt<'tcx>) -> Option<DependencyList> {
     let sess = &tcx.sess;
     let crates = cstore::used_crates(tcx, RequireStatic);
     if !crates.iter().by_ref().all(|&(_, ref p)| p.is_some()) {
@@ -324,7 +324,7 @@ fn activate_injected_dep(injected: Option<CrateNum>,
 
 // After the linkage for a crate has been determined we need to verify that
 // there's only going to be one allocator in the output.
-fn verify_ok<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, list: &[Linkage]) {
+fn verify_ok<'tcx>(tcx: TyCtxt<'tcx>, list: &[Linkage]) {
     let sess = &tcx.sess;
     if list.len() == 0 {
         return

src/librustc/middle/entry.rs

@@ -47,7 +47,7 @@ impl<'a, 'tcx> ItemLikeVisitor<'tcx> for EntryContext<'a, 'tcx> {
     }
 }
 
-fn entry_fn(tcx: TyCtxt<'_, '_>, cnum: CrateNum) -> Option<(DefId, EntryFnType)> {
+fn entry_fn(tcx: TyCtxt<'_>, cnum: CrateNum) -> Option<(DefId, EntryFnType)> {
     assert_eq!(cnum, LOCAL_CRATE);
 
     let any_exe = tcx.sess.crate_types.borrow().iter().any(|ty| {
@@ -141,7 +141,7 @@ fn find_item(item: &Item, ctxt: &mut EntryContext<'_, '_>, at_root: bool) {
 }
 
 fn configure_main(
-    tcx: TyCtxt<'_, '_>,
+    tcx: TyCtxt<'_>,
     visitor: &EntryContext<'_, '_>,
 ) -> Option<(DefId, EntryFnType)> {
     if let Some((hir_id, _)) = visitor.start_fn {
@@ -179,7 +179,7 @@ fn configure_main(
     }
 }
 
-pub fn find_entry_point(tcx: TyCtxt<'_, '_>) -> Option<(DefId, EntryFnType)> {
+pub fn find_entry_point(tcx: TyCtxt<'_>) -> Option<(DefId, EntryFnType)> {
     tcx.entry_fn(LOCAL_CRATE)
 }
 

src/librustc/middle/exported_symbols.rs

@@ -38,7 +38,7 @@ pub enum ExportedSymbol<'tcx> {
 }
 
 impl<'tcx> ExportedSymbol<'tcx> {
-    pub fn symbol_name(&self, tcx: TyCtxt<'tcx, '_>) -> ty::SymbolName {
+    pub fn symbol_name(&self, tcx: TyCtxt<'tcx>) -> ty::SymbolName {
         match *self {
             ExportedSymbol::NonGeneric(def_id) => {
                 tcx.symbol_name(ty::Instance::mono(tcx, def_id))
@@ -54,7 +54,7 @@ impl<'tcx> ExportedSymbol<'tcx> {
 
     pub fn compare_stable(
         &self,
-        tcx: TyCtxt<'tcx, '_>,
+        tcx: TyCtxt<'tcx>,
         other: &ExportedSymbol<'tcx>,
     ) -> cmp::Ordering {
         match *self {
@@ -91,13 +91,13 @@ impl<'tcx> ExportedSymbol<'tcx> {
     }
 }
 
-pub fn metadata_symbol_name(tcx: TyCtxt<'_, '_>) -> String {
+pub fn metadata_symbol_name(tcx: TyCtxt<'_>) -> String {
     format!("rust_metadata_{}_{}",
             tcx.original_crate_name(LOCAL_CRATE),
             tcx.crate_disambiguator(LOCAL_CRATE).to_fingerprint().to_hex())
 }
 
-impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ExportedSymbol<'gcx> {
+impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ExportedSymbol<'tcx> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {

src/librustc/middle/expr_use_visitor.rs

@@ -202,7 +202,7 @@ enum OverloadedCallType {
 }
 
 impl OverloadedCallType {
-    fn from_trait_id(tcx: TyCtxt<'_, '_>, trait_id: DefId) -> OverloadedCallType {
+    fn from_trait_id(tcx: TyCtxt<'_>, trait_id: DefId) -> OverloadedCallType {
         for &(maybe_function_trait, overloaded_call_type) in &[
             (tcx.lang_items().fn_once_trait(), FnOnceOverloadedCall),
             (tcx.lang_items().fn_mut_trait(), FnMutOverloadedCall),
@@ -219,7 +219,7 @@ impl OverloadedCallType {
         bug!("overloaded call didn't map to known function trait")
     }
 
-    fn from_method_id(tcx: TyCtxt<'_, '_>, method_id: DefId) -> OverloadedCallType {
+    fn from_method_id(tcx: TyCtxt<'_>, method_id: DefId) -> OverloadedCallType {
         let method = tcx.associated_item(method_id);
         OverloadedCallType::from_trait_id(tcx, method.container.id())
     }
@@ -229,8 +229,8 @@ impl OverloadedCallType {
 // The ExprUseVisitor type
 //
 // This is the code that actually walks the tree.
-pub struct ExprUseVisitor<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
-    mc: mc::MemCategorizationContext<'a, 'gcx, 'tcx>,
+pub struct ExprUseVisitor<'a, 'tcx: 'a> {
+    mc: mc::MemCategorizationContext<'a, 'tcx>,
     delegate: &'a mut dyn Delegate<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
 }
@@ -254,7 +254,7 @@ macro_rules! return_if_err {
     )
 }
 
-impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx, 'tcx> {
+impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
     /// Creates the ExprUseVisitor, configuring it with the various options provided:
     ///
     /// - `delegate` -- who receives the callbacks
@@ -268,7 +268,7 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx, 'tcx> {
     /// See also `with_infer`, which is used *during* typeck.
     pub fn new(
         delegate: &'a mut (dyn Delegate<'tcx> + 'a),
-        tcx: TyCtxt<'tcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         body_owner: DefId,
         param_env: ty::ParamEnv<'tcx>,
         region_scope_tree: &'a region::ScopeTree,
@@ -287,9 +287,9 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
     pub fn with_infer(delegate: &'a mut (dyn Delegate<'tcx>+'a),
-                      infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+                      infcx: &'a InferCtxt<'a, 'tcx>,
                       body_owner: DefId,
                       param_env: ty::ParamEnv<'tcx>,
                       region_scope_tree: &'a region::ScopeTree,
@@ -333,7 +333,7 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
         self.consume_expr(&body.value);
     }
 
-    fn tcx(&self) -> TyCtxt<'gcx, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
         self.mc.tcx
     }
 
@@ -974,7 +974,7 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
     }
 }
 
-fn copy_or_move<'a, 'gcx, 'tcx>(mc: &mc::MemCategorizationContext<'a, 'gcx, 'tcx>,
+fn copy_or_move<'a, 'tcx>(mc: &mc::MemCategorizationContext<'a, 'tcx>,
                                 param_env: ty::ParamEnv<'tcx>,
                                 cmt: &mc::cmt_<'tcx>,
                                 move_reason: MoveReason)

src/librustc/middle/free_region.rs

@@ -15,8 +15,8 @@ use crate::ty::{self, TyCtxt, Region};
 ///
 /// This stuff is a bit convoluted and should be refactored, but as we
 /// transition to NLL, it'll all go away anyhow.
-pub struct RegionRelations<'a, 'gcx: 'tcx, 'tcx: 'a> {
-    pub tcx: TyCtxt<'gcx, 'tcx>,
+pub struct RegionRelations<'a, 'tcx: 'a> {
+    pub tcx: TyCtxt<'tcx>,
 
     /// The context used to fetch the region maps.
     pub context: DefId,
@@ -28,9 +28,9 @@ pub struct RegionRelations<'a, 'gcx: 'tcx, 'tcx: 'a> {
     pub free_regions: &'a FreeRegionMap<'tcx>,
 }
 
-impl<'a, 'gcx, 'tcx> RegionRelations<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> RegionRelations<'a, 'tcx> {
     pub fn new(
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         context: DefId,
         region_scope_tree: &'a region::ScopeTree,
         free_regions: &'a FreeRegionMap<'tcx>,

src/librustc/middle/intrinsicck.rs

@@ -10,7 +10,7 @@ use syntax_pos::{Span, sym};
 use crate::hir::intravisit::{self, Visitor, NestedVisitorMap};
 use crate::hir;
 
-fn check_mod_intrinsics<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, module_def_id: DefId) {
+fn check_mod_intrinsics<'tcx>(tcx: TyCtxt<'tcx>, module_def_id: DefId) {
     tcx.hir().visit_item_likes_in_module(
         module_def_id,
         &mut ItemVisitor { tcx }.as_deep_visitor()
@@ -25,18 +25,18 @@ pub fn provide(providers: &mut Providers<'_>) {
 }
 
 struct ItemVisitor<'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
 }
 
 struct ExprVisitor<'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     tables: &'tcx ty::TypeckTables<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
 }
 
 /// If the type is `Option<T>`, it will return `T`, otherwise
 /// the type itself. Works on most `Option`-like types.
-fn unpack_option_like<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
+fn unpack_option_like<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
     let (def, substs) = match ty.sty {
         ty::Adt(def, substs) => (def, substs),
         _ => return ty

src/librustc/middle/lang_items.rs

@@ -106,7 +106,7 @@ impl LanguageItems {
 
 struct LanguageItemCollector<'tcx> {
     items: LanguageItems,
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     /// A mapping from the name of the lang item to its order and the form it must be of.
     item_refs: FxHashMap<&'static str, (usize, Target)>,
 }
@@ -160,7 +160,7 @@ impl ItemLikeVisitor<'v> for LanguageItemCollector<'tcx> {
 }
 
 impl LanguageItemCollector<'tcx> {
-    fn new(tcx: TyCtxt<'tcx, 'tcx>) -> LanguageItemCollector<'tcx> {
+    fn new(tcx: TyCtxt<'tcx>) -> LanguageItemCollector<'tcx> {
         let mut item_refs = FxHashMap::default();
 
         $( item_refs.insert($name, ($variant as usize, $target)); )*
@@ -217,7 +217,7 @@ pub fn extract(attrs: &[ast::Attribute]) -> Option<(Symbol, Span)> {
 }
 
 /// Traverse and collect all the lang items in all crates.
-pub fn collect<'tcx>(tcx: TyCtxt<'tcx, 'tcx>) -> LanguageItems {
+pub fn collect<'tcx>(tcx: TyCtxt<'tcx>) -> LanguageItems {
     // Initialize the collector.
     let mut collector = LanguageItemCollector::new(tcx);
 
@@ -402,7 +402,7 @@ language_item_table! {
     Rc,                          "rc",                 rc,                      Target::Struct;
 }
 
-impl<'tcx, 'gcx> TyCtxt<'tcx, 'gcx> {
+impl<'tcx> TyCtxt<'tcx> {
     /// Returns the `DefId` for a given `LangItem`.
     /// If not found, fatally abort compilation.
     pub fn require_lang_item(&self, lang_item: LangItem) -> DefId {

src/librustc/middle/lib_features.rs

@@ -38,12 +38,12 @@ impl LibFeatures {
 }
 
 pub struct LibFeatureCollector<'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     lib_features: LibFeatures,
 }
 
 impl LibFeatureCollector<'tcx> {
-    fn new(tcx: TyCtxt<'tcx, 'tcx>) -> LibFeatureCollector<'tcx> {
+    fn new(tcx: TyCtxt<'tcx>) -> LibFeatureCollector<'tcx> {
         LibFeatureCollector {
             tcx,
             lib_features: LibFeatures::new(),
@@ -142,7 +142,7 @@ impl Visitor<'tcx> for LibFeatureCollector<'tcx> {
     }
 }
 
-pub fn collect<'tcx>(tcx: TyCtxt<'tcx, 'tcx>) -> LibFeatures {
+pub fn collect<'tcx>(tcx: TyCtxt<'tcx>) -> LibFeatures {
     let mut collector = LibFeatureCollector::new(tcx);
     intravisit::walk_crate(&mut collector, tcx.hir().krate());
     collector.lib_features

src/librustc/middle/liveness.rs

@@ -150,7 +150,7 @@ enum LiveNodeKind {
     ExitNode
 }
 
-fn live_node_kind_to_string(lnk: LiveNodeKind, tcx: TyCtxt<'_, '_>) -> String {
+fn live_node_kind_to_string(lnk: LiveNodeKind, tcx: TyCtxt<'_>) -> String {
     let cm = tcx.sess.source_map();
     match lnk {
         UpvarNode(s) => {
@@ -181,7 +181,7 @@ impl<'tcx> Visitor<'tcx> for IrMaps<'tcx> {
     fn visit_arm(&mut self, a: &'tcx hir::Arm) { visit_arm(self, a); }
 }
 
-fn check_mod_liveness<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, module_def_id: DefId) {
+fn check_mod_liveness<'tcx>(tcx: TyCtxt<'tcx>, module_def_id: DefId) {
     tcx.hir().visit_item_likes_in_module(
         module_def_id,
         &mut IrMaps::new(tcx, module_def_id).as_deep_visitor(),
@@ -257,7 +257,7 @@ enum VarKind {
 }
 
 struct IrMaps<'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     body_owner: DefId,
     num_live_nodes: usize,
     num_vars: usize,
@@ -269,7 +269,7 @@ struct IrMaps<'tcx> {
 }
 
 impl IrMaps<'tcx> {
-    fn new(tcx: TyCtxt<'tcx, 'tcx>, body_owner: DefId) -> IrMaps<'tcx> {
+    fn new(tcx: TyCtxt<'tcx>, body_owner: DefId) -> IrMaps<'tcx> {
         IrMaps {
             tcx,
             body_owner,

src/librustc/middle/mem_categorization.rs

@@ -287,14 +287,14 @@ impl HirNode for hir::Pat {
 }
 
 #[derive(Clone)]
-pub struct MemCategorizationContext<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
-    pub tcx: TyCtxt<'gcx, 'tcx>,
+pub struct MemCategorizationContext<'a, 'tcx> {
+    pub tcx: TyCtxt<'tcx>,
     pub body_owner: DefId,
     pub upvars: Option<&'tcx FxIndexMap<hir::HirId, hir::Upvar>>,
     pub region_scope_tree: &'a region::ScopeTree,
     pub tables: &'a ty::TypeckTables<'tcx>,
     rvalue_promotable_map: Option<&'tcx ItemLocalSet>,
-    infcx: Option<&'a InferCtxt<'a, 'gcx, 'tcx>>,
+    infcx: Option<&'a InferCtxt<'a, 'tcx>>,
 }
 
 pub type McResult<T> = Result<T, ()>;
@@ -340,7 +340,7 @@ impl MutabilityCategory {
     }
 
     fn from_local(
-        tcx: TyCtxt<'_, '_>,
+        tcx: TyCtxt<'_>,
         tables: &ty::TypeckTables<'_>,
         id: ast::NodeId,
     ) -> MutabilityCategory {
@@ -402,14 +402,14 @@ impl MutabilityCategory {
     }
 }
 
-impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx, 'tcx> {
+impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
     pub fn new(
-        tcx: TyCtxt<'tcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         body_owner: DefId,
         region_scope_tree: &'a region::ScopeTree,
         tables: &'a ty::TypeckTables<'tcx>,
         rvalue_promotable_map: Option<&'tcx ItemLocalSet>,
-    ) -> MemCategorizationContext<'a, 'tcx, 'tcx> {
+    ) -> MemCategorizationContext<'a, 'tcx> {
         MemCategorizationContext {
             tcx,
             body_owner,
@@ -422,7 +422,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
     /// Creates a `MemCategorizationContext` during type inference.
     /// This is used during upvar analysis and a few other places.
     /// Because the typeck tables are not yet complete, the results
@@ -432,11 +432,11 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
     ///   temporaries may be overly conservative;
     /// - similarly, as the results of upvar analysis are not yet
     ///   known, the results around upvar accesses may be incorrect.
-    pub fn with_infer(infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+    pub fn with_infer(infcx: &'a InferCtxt<'a, 'tcx>,
                       body_owner: DefId,
                       region_scope_tree: &'a region::ScopeTree,
                       tables: &'a ty::TypeckTables<'tcx>)
-                      -> MemCategorizationContext<'a, 'gcx, 'tcx> {
+                      -> MemCategorizationContext<'a, 'tcx> {
         let tcx = infcx.tcx;
 
         // Subtle: we can't do rvalue promotion analysis until the
@@ -586,7 +586,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
     pub fn cat_expr(&self, expr: &hir::Expr) -> McResult<cmt_<'tcx>> {
         // This recursion helper avoids going through *too many*
         // adjustments, since *only* non-overloaded deref recurses.
-        fn helper<'a, 'gcx, 'tcx>(mc: &MemCategorizationContext<'a, 'gcx, 'tcx>,
+        fn helper<'a, 'tcx>(mc: &MemCategorizationContext<'a, 'tcx>,
                                   expr: &hir::Expr,
                                   adjustments: &[adjustment::Adjustment<'tcx>])
                                   -> McResult<cmt_<'tcx>> {
@@ -1518,7 +1518,7 @@ impl<'tcx> cmt_<'tcx> {
         }
     }
 
-    pub fn descriptive_string(&self, tcx: TyCtxt<'_, '_>) -> Cow<'static, str> {
+    pub fn descriptive_string(&self, tcx: TyCtxt<'_>) -> Cow<'static, str> {
         match self.cat {
             Categorization::StaticItem => {
                 "static item".into()

src/librustc/middle/reachable.rs

@@ -27,7 +27,7 @@ use crate::hir::intravisit;
 // Returns true if the given item must be inlined because it may be
 // monomorphized or it was marked with `#[inline]`. This will only return
 // true for functions.
-fn item_might_be_inlined(tcx: TyCtxt<'tcx, 'tcx>, item: &hir::Item, attrs: CodegenFnAttrs) -> bool {
+fn item_might_be_inlined(tcx: TyCtxt<'tcx>, item: &hir::Item, attrs: CodegenFnAttrs) -> bool {
     if attrs.requests_inline() {
         return true
     }
@@ -43,7 +43,7 @@ fn item_might_be_inlined(tcx: TyCtxt<'tcx, 'tcx>, item: &hir::Item, attrs: Codeg
 }
 
 fn method_might_be_inlined<'tcx>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     impl_item: &hir::ImplItem,
     impl_src: DefId,
 ) -> bool {
@@ -67,7 +67,7 @@ fn method_might_be_inlined<'tcx>(
 // Information needed while computing reachability.
 struct ReachableContext<'a, 'tcx: 'a> {
     // The type context.
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     tables: &'a ty::TypeckTables<'tcx>,
     // The set of items which must be exported in the linkage sense.
     reachable_symbols: HirIdSet,
@@ -335,7 +335,7 @@ impl<'a, 'tcx> ReachableContext<'a, 'tcx> {
 // trait items are used from inlinable code through method call syntax or UFCS, or their
 // trait is a lang item.
 struct CollectPrivateImplItemsVisitor<'a, 'tcx: 'a> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     access_levels: &'a privacy::AccessLevels,
     worklist: &'a mut Vec<hir::HirId>,
 }
@@ -391,7 +391,7 @@ impl<'a, 'tcx: 'a> ItemLikeVisitor<'tcx> for CollectPrivateImplItemsVisitor<'a,
 #[derive(Clone, HashStable)]
 pub struct ReachableSet(pub Lrc<HirIdSet>);
 
-fn reachable_set<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, crate_num: CrateNum) -> ReachableSet {
+fn reachable_set<'tcx>(tcx: TyCtxt<'tcx>, crate_num: CrateNum) -> ReachableSet {
     debug_assert!(crate_num == LOCAL_CRATE);
 
     let access_levels = &tcx.privacy_access_levels(LOCAL_CRATE);

src/librustc/middle/region.rs

@@ -169,7 +169,7 @@ impl Scope {
         self.id
     }
 
-    pub fn node_id(&self, tcx: TyCtxt<'_, '_>, scope_tree: &ScopeTree) -> ast::NodeId {
+    pub fn node_id(&self, tcx: TyCtxt<'_>, scope_tree: &ScopeTree) -> ast::NodeId {
         match scope_tree.root_body {
             Some(hir_id) => {
                 tcx.hir().hir_to_node_id(hir::HirId {
@@ -184,7 +184,7 @@ impl Scope {
     /// Returns the span of this `Scope`. Note that in general the
     /// returned span may not correspond to the span of any `NodeId` in
     /// the AST.
-    pub fn span(&self, tcx: TyCtxt<'_, '_>, scope_tree: &ScopeTree) -> Span {
+    pub fn span(&self, tcx: TyCtxt<'_>, scope_tree: &ScopeTree) -> Span {
         let node_id = self.node_id(tcx, scope_tree);
         if node_id == ast::DUMMY_NODE_ID {
             return DUMMY_SP;
@@ -359,7 +359,7 @@ pub struct Context {
 }
 
 struct RegionResolutionVisitor<'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
 
     // The number of expressions and patterns visited in the current body
     expr_and_pat_count: usize,
@@ -646,9 +646,9 @@ impl<'tcx> ScopeTree {
 
     /// Assuming that the provided region was defined within this `ScopeTree`,
     /// returns the outermost `Scope` that the region outlives.
-    pub fn early_free_scope<'gcx>(
+    pub fn early_free_scope(
         &self,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         br: &ty::EarlyBoundRegion,
     ) -> Scope {
         let param_owner = tcx.parent(br.def_id).unwrap();
@@ -679,7 +679,7 @@ impl<'tcx> ScopeTree {
 
     /// Assuming that the provided region was defined within this `ScopeTree`,
     /// returns the outermost `Scope` that the region outlives.
-    pub fn free_scope<'gcx>(&self, tcx: TyCtxt<'gcx, 'tcx>, fr: &ty::FreeRegion) -> Scope {
+    pub fn free_scope(&self, tcx: TyCtxt<'tcx>, fr: &ty::FreeRegion) -> Scope {
         let param_owner = match fr.bound_region {
             ty::BoundRegion::BrNamed(def_id, _) => {
                 tcx.parent(def_id).unwrap()
@@ -1334,7 +1334,7 @@ impl<'tcx> Visitor<'tcx> for RegionResolutionVisitor<'tcx> {
     }
 }
 
-fn region_scope_tree<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, def_id: DefId) -> &'tcx ScopeTree {
+fn region_scope_tree<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx ScopeTree {
     let closure_base_def_id = tcx.closure_base_def_id(def_id);
     if closure_base_def_id != def_id {
         return tcx.region_scope_tree(closure_base_def_id);

src/librustc/middle/resolve_lifetime.rs

@@ -218,7 +218,7 @@ impl_stable_hash_for!(struct crate::middle::resolve_lifetime::ResolveLifetimes {
 });
 
 struct LifetimeContext<'a, 'tcx: 'a> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     map: &'a mut NamedRegionMap,
     scope: ScopeRef<'a>,
 
@@ -368,7 +368,7 @@ pub fn provide(providers: &mut ty::query::Providers<'_>) {
 /// entire crate. You should not read the result of this query
 /// directly, but rather use `named_region_map`, `is_late_bound_map`,
 /// etc.
-fn resolve_lifetimes<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, for_krate: CrateNum) -> &'tcx ResolveLifetimes {
+fn resolve_lifetimes<'tcx>(tcx: TyCtxt<'tcx>, for_krate: CrateNum) -> &'tcx ResolveLifetimes {
     assert_eq!(for_krate, LOCAL_CRATE);
 
     let named_region_map = krate(tcx);
@@ -395,7 +395,7 @@ fn resolve_lifetimes<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, for_krate: CrateNum) -> &'tc
     tcx.arena.alloc(rl)
 }
 
-fn krate<'tcx>(tcx: TyCtxt<'tcx, 'tcx>) -> NamedRegionMap {
+fn krate<'tcx>(tcx: TyCtxt<'tcx>) -> NamedRegionMap {
     let krate = tcx.hir().krate();
     let mut map = NamedRegionMap {
         defs: Default::default(),
@@ -1098,7 +1098,7 @@ impl ShadowKind {
     }
 }
 
-fn check_mixed_explicit_and_in_band_defs(tcx: TyCtxt<'_, '_>, params: &P<[hir::GenericParam]>) {
+fn check_mixed_explicit_and_in_band_defs(tcx: TyCtxt<'_>, params: &P<[hir::GenericParam]>) {
     let lifetime_params: Vec<_> = params
         .iter()
         .filter_map(|param| match param.kind {
@@ -1126,7 +1126,7 @@ fn check_mixed_explicit_and_in_band_defs(tcx: TyCtxt<'_, '_>, params: &P<[hir::G
 }
 
 fn signal_shadowing_problem(
-    tcx: TyCtxt<'_, '_>,
+    tcx: TyCtxt<'_>,
     name: ast::Name,
     orig: Original,
     shadower: Shadower,
@@ -1166,7 +1166,7 @@ fn signal_shadowing_problem(
 // if one of the label shadows a lifetime or another label.
 fn extract_labels(ctxt: &mut LifetimeContext<'_, '_>, body: &hir::Body) {
     struct GatherLabels<'a, 'tcx: 'a> {
-        tcx: TyCtxt<'tcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         scope: ScopeRef<'a>,
         labels_in_fn: &'a mut Vec<ast::Ident>,
     }
@@ -1215,7 +1215,7 @@ fn extract_labels(ctxt: &mut LifetimeContext<'_, '_>, body: &hir::Body) {
     }
 
     fn check_if_label_shadows_lifetime(
-        tcx: TyCtxt<'_, '_>,
+        tcx: TyCtxt<'_>,
         mut scope: ScopeRef<'_>,
         label: ast::Ident,
     ) {
@@ -1253,7 +1253,7 @@ fn extract_labels(ctxt: &mut LifetimeContext<'_, '_>, body: &hir::Body) {
     }
 }
 
-fn compute_object_lifetime_defaults(tcx: TyCtxt<'_, '_>) -> HirIdMap<Vec<ObjectLifetimeDefault>> {
+fn compute_object_lifetime_defaults(tcx: TyCtxt<'_>) -> HirIdMap<Vec<ObjectLifetimeDefault>> {
     let mut map = HirIdMap::default();
     for item in tcx.hir().krate().items.values() {
         match item.node {
@@ -1310,7 +1310,7 @@ fn compute_object_lifetime_defaults(tcx: TyCtxt<'_, '_>) -> HirIdMap<Vec<ObjectL
 /// of the form `T:'a` so as to determine the `ObjectLifetimeDefault`
 /// for each type parameter.
 fn object_lifetime_defaults_for_item(
-    tcx: TyCtxt<'_, '_>,
+    tcx: TyCtxt<'_>,
     generics: &hir::Generics,
 ) -> Vec<ObjectLifetimeDefault> {
     fn add_bounds(set: &mut Set1<hir::LifetimeName>, bounds: &[hir::GenericBound]) {

src/librustc/middle/stability.rs

@@ -106,7 +106,7 @@ impl_stable_hash_for!(struct self::Index<'tcx> {
 
 // A private tree-walker for producing an Index.
 struct Annotator<'a, 'tcx: 'a> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     index: &'a mut Index<'tcx>,
     parent_stab: Option<&'tcx Stability>,
     parent_depr: Option<DeprecationEntry>,
@@ -317,7 +317,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Annotator<'a, 'tcx> {
 }
 
 struct MissingStabilityAnnotations<'a, 'tcx: 'a> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     access_levels: &'a AccessLevels,
 }
 
@@ -390,7 +390,7 @@ impl<'a, 'tcx> Visitor<'tcx> for MissingStabilityAnnotations<'a, 'tcx> {
 }
 
 impl<'tcx> Index<'tcx> {
-    pub fn new(tcx: TyCtxt<'tcx, 'tcx>) -> Index<'tcx> {
+    pub fn new(tcx: TyCtxt<'tcx>) -> Index<'tcx> {
         let is_staged_api =
             tcx.sess.opts.debugging_opts.force_unstable_if_unmarked ||
             tcx.features().staged_api;
@@ -466,7 +466,7 @@ impl<'tcx> Index<'tcx> {
 
 /// Cross-references the feature names of unstable APIs with enabled
 /// features and possibly prints errors.
-fn check_mod_unstable_api_usage<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, module_def_id: DefId) {
+fn check_mod_unstable_api_usage<'tcx>(tcx: TyCtxt<'tcx>, module_def_id: DefId) {
     tcx.hir().visit_item_likes_in_module(module_def_id, &mut Checker { tcx }.as_deep_visitor());
 }
 
@@ -502,7 +502,7 @@ pub fn deprecation_in_effect(since: &str) -> bool {
 }
 
 struct Checker<'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
 }
 
 /// Result of `TyCtxt::eval_stability`.
@@ -521,7 +521,7 @@ pub enum EvalResult {
     Unmarked,
 }
 
-impl<'gcx, 'tcx> TyCtxt<'gcx, 'tcx> {
+impl<'tcx> TyCtxt<'tcx> {
     // See issue #38412.
     fn skip_stability_check_due_to_privacy(self, mut def_id: DefId) -> bool {
         // Check if `def_id` is a trait method.
@@ -827,7 +827,7 @@ impl Visitor<'tcx> for Checker<'tcx> {
     }
 }
 
-impl<'gcx, 'tcx> TyCtxt<'gcx, 'tcx> {
+impl<'tcx> TyCtxt<'tcx> {
     pub fn lookup_deprecation(self, id: DefId) -> Option<Deprecation> {
         self.lookup_deprecation_entry(id).map(|depr| depr.attr)
     }
@@ -836,7 +836,7 @@ impl<'gcx, 'tcx> TyCtxt<'gcx, 'tcx> {
 /// Given the list of enabled features that were not language features (i.e., that
 /// were expected to be library features), and the list of features used from
 /// libraries, identify activated features that don't exist and error about them.
-pub fn check_unused_or_stable_features<'tcx>(tcx: TyCtxt<'tcx, 'tcx>) {
+pub fn check_unused_or_stable_features<'tcx>(tcx: TyCtxt<'tcx>) {
     let access_levels = &tcx.privacy_access_levels(LOCAL_CRATE);
 
     if tcx.stability().staged_api[&LOCAL_CRATE] {
@@ -921,7 +921,7 @@ pub fn check_unused_or_stable_features<'tcx>(tcx: TyCtxt<'tcx, 'tcx>) {
 }
 
 fn unnecessary_stable_feature_lint<'tcx>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     span: Span,
     feature: Symbol,
     since: Symbol,

src/librustc/middle/weak_lang_items.rs

@@ -18,13 +18,13 @@ macro_rules! weak_lang_items {
     ($($name:ident, $item:ident, $sym:ident;)*) => (
 
 struct Context<'a, 'tcx: 'a> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     items: &'a mut lang_items::LanguageItems,
 }
 
 /// Checks the crate for usage of weak lang items, returning a vector of all the
 /// language items required by this crate, but not defined yet.
-pub fn check_crate<'tcx>(tcx: TyCtxt<'tcx, 'tcx>,
+pub fn check_crate<'tcx>(tcx: TyCtxt<'tcx>,
                              items: &mut lang_items::LanguageItems) {
     // These are never called by user code, they're generated by the compiler.
     // They will never implicitly be added to the `missing` array unless we do
@@ -60,7 +60,7 @@ pub fn link_name(attrs: &[ast::Attribute]) -> Option<Symbol> {
 /// Not all lang items are always required for each compilation, particularly in
 /// the case of panic=abort. In these situations some lang items are injected by
 /// crates and don't actually need to be defined in libstd.
-pub fn whitelisted(tcx: TyCtxt<'_, '_>, lang_item: lang_items::LangItem) -> bool {
+pub fn whitelisted(tcx: TyCtxt<'_>, lang_item: lang_items::LangItem) -> bool {
     // If we're not compiling with unwinding, we won't actually need these
     // symbols. Other panic runtimes ensure that the relevant symbols are
     // available to link things together, but they're never exercised.
@@ -72,7 +72,7 @@ pub fn whitelisted(tcx: TyCtxt<'_, '_>, lang_item: lang_items::LangItem) -> bool
     false
 }
 
-fn verify<'tcx>(tcx: TyCtxt<'tcx, 'tcx>,
+fn verify<'tcx>(tcx: TyCtxt<'tcx>,
                     items: &lang_items::LanguageItems) {
     // We only need to check for the presence of weak lang items if we're
     // emitting something that's not an rlib.
@@ -142,7 +142,7 @@ impl<'a, 'tcx, 'v> Visitor<'v> for Context<'a, 'tcx> {
     }
 }
 
-impl<'tcx, 'gcx> TyCtxt<'tcx, 'gcx> {
+impl<'tcx> TyCtxt<'tcx> {
     pub fn is_weak_lang_item(&self, item_def_id: DefId) -> bool {
         let lang_items = self.lang_items();
         let did = Some(item_def_id);

src/librustc/mir/interpret/error.rs

@@ -74,16 +74,16 @@ impl<'tcx> fmt::Display for FrameInfo<'tcx> {
     }
 }
 
-impl<'gcx, 'tcx> ConstEvalErr<'tcx> {
+impl<'tcx> ConstEvalErr<'tcx> {
     pub fn struct_error(
         &self,
-        tcx: TyCtxtAt<'gcx, 'tcx>,
+        tcx: TyCtxtAt<'tcx>,
         message: &str,
     ) -> Result<DiagnosticBuilder<'tcx>, ErrorHandled> {
         self.struct_generic(tcx, message, None)
     }
 
-    pub fn report_as_error(&self, tcx: TyCtxtAt<'gcx, 'tcx>, message: &str) -> ErrorHandled {
+    pub fn report_as_error(&self, tcx: TyCtxtAt<'tcx>, message: &str) -> ErrorHandled {
         let err = self.struct_error(tcx, message);
         match err {
             Ok(mut err) => {
@@ -96,7 +96,7 @@ impl<'gcx, 'tcx> ConstEvalErr<'tcx> {
 
     pub fn report_as_lint(
         &self,
-        tcx: TyCtxtAt<'gcx, 'tcx>,
+        tcx: TyCtxtAt<'tcx>,
         message: &str,
         lint_root: hir::HirId,
         span: Option<Span>,
@@ -129,7 +129,7 @@ impl<'gcx, 'tcx> ConstEvalErr<'tcx> {
 
     fn struct_generic(
         &self,
-        tcx: TyCtxtAt<'gcx, 'tcx>,
+        tcx: TyCtxtAt<'tcx>,
         message: &str,
         lint_root: Option<hir::HirId>,
     ) -> Result<DiagnosticBuilder<'tcx>, ErrorHandled> {
@@ -170,7 +170,7 @@ impl<'gcx, 'tcx> ConstEvalErr<'tcx> {
     }
 }
 
-pub fn struct_error<'gcx, 'tcx>(tcx: TyCtxtAt<'gcx, 'tcx>, msg: &str) -> DiagnosticBuilder<'tcx> {
+pub fn struct_error<'tcx>(tcx: TyCtxtAt<'tcx>, msg: &str) -> DiagnosticBuilder<'tcx> {
     struct_span_err!(tcx.sess, tcx.span, E0080, "{}", msg)
 }
 

src/librustc/mir/interpret/mod.rs

@@ -66,7 +66,7 @@ enum AllocDiscriminant {
 
 pub fn specialized_encode_alloc_id<'tcx, E: Encoder>(
     encoder: &mut E,
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     alloc_id: AllocId,
 ) -> Result<(), E::Error> {
     let alloc: GlobalAlloc<'tcx> =

src/librustc/mir/mod.rs

@@ -1240,8 +1240,8 @@ impl<'tcx> Terminator<'tcx> {
 }
 
 impl<'tcx> TerminatorKind<'tcx> {
-    pub fn if_<'gcx>(
-        tcx: TyCtxt<'gcx, 'tcx>,
+    pub fn if_(
+        tcx: TyCtxt<'tcx>,
         cond: Operand<'tcx>,
         t: BasicBlock,
         f: BasicBlock,
@@ -2324,7 +2324,7 @@ impl<'tcx> Operand<'tcx> {
     /// with given `DefId` and substs. Since this is used to synthesize
     /// MIR, assumes `user_ty` is None.
     pub fn function_handle(
-        tcx: TyCtxt<'tcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         def_id: DefId,
         substs: SubstsRef<'tcx>,
         span: Span,
@@ -2795,7 +2795,7 @@ impl UserTypeProjection {
 CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
 
 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
         use crate::mir::ProjectionElem::*;
 
         let base = self.base.fold_with(folder);
@@ -3012,8 +3012,8 @@ pub struct GeneratorLayout<'tcx> {
 }
 
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
-pub struct BorrowCheckResult<'gcx> {
-    pub closure_requirements: Option<ClosureRegionRequirements<'gcx>>,
+pub struct BorrowCheckResult<'tcx> {
+    pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
     pub used_mut_upvars: SmallVec<[Field; 8]>,
 }
 
@@ -3068,7 +3068,7 @@ pub struct BorrowCheckResult<'gcx> {
 /// TyCtxt, and hence we cannot use `ReVar` (which is what we use
 /// internally within the rest of the NLL code).
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
-pub struct ClosureRegionRequirements<'gcx> {
+pub struct ClosureRegionRequirements<'tcx> {
     /// The number of external regions defined on the closure. In our
     /// example above, it would be 3 -- one for `'static`, then `'1`
     /// and `'2`. This is just used for a sanity check later on, to
@@ -3078,7 +3078,7 @@ pub struct ClosureRegionRequirements<'gcx> {
 
     /// Requirements between the various free regions defined in
     /// indices.
-    pub outlives_requirements: Vec<ClosureOutlivesRequirement<'gcx>>,
+    pub outlives_requirements: Vec<ClosureOutlivesRequirement<'tcx>>,
 }
 
 /// Indicates an outlives constraint between a type or between two
@@ -3262,7 +3262,7 @@ EnumTypeFoldableImpl! {
 }
 
 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
         use crate::mir::TerminatorKind::*;
 
         let kind = match self.kind {
@@ -3430,7 +3430,7 @@ impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
 }
 
 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
         match self {
             &Place::Projection(ref p) => Place::Projection(p.fold_with(folder)),
             _ => self.clone(),
@@ -3447,7 +3447,7 @@ impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
 }
 
 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
         use crate::mir::Rvalue::*;
         match *self {
             Use(ref op) => Use(op.fold_with(folder)),
@@ -3519,7 +3519,7 @@ impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
 }
 
 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
         match *self {
             Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
             Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
@@ -3536,7 +3536,7 @@ impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
 }
 
 impl<'tcx> TypeFoldable<'tcx> for Projection<'tcx> {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
         use crate::mir::ProjectionElem::*;
 
         let base = self.base.fold_with(folder);
@@ -3562,7 +3562,7 @@ impl<'tcx> TypeFoldable<'tcx> for Projection<'tcx> {
 }
 
 impl<'tcx> TypeFoldable<'tcx> for Field {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> Self {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
         *self
     }
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
@@ -3571,7 +3571,7 @@ impl<'tcx> TypeFoldable<'tcx> for Field {
 }
 
 impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> Self {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
         *self
     }
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
@@ -3580,7 +3580,7 @@ impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
 }
 
 impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> Self {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
         self.clone()
     }
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
@@ -3589,7 +3589,7 @@ impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
 }
 
 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
+    fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
         Constant {
             span: self.span.clone(),
             ty: self.ty.fold_with(folder),

src/librustc/mir/mono.rs

@@ -48,7 +48,7 @@ pub enum MonoItem<'tcx> {
 }
 
 impl<'tcx> MonoItem<'tcx> {
-    pub fn size_estimate(&self, tcx: TyCtxt<'tcx, 'tcx>) -> usize {
+    pub fn size_estimate(&self, tcx: TyCtxt<'tcx>) -> usize {
         match *self {
             MonoItem::Fn(instance) => {
                 // Estimate the size of a function based on how many statements
@@ -72,7 +72,7 @@ impl<'tcx> MonoItem<'tcx> {
         }
     }
 
-    pub fn symbol_name(&self, tcx: TyCtxt<'tcx, 'tcx>) -> SymbolName {
+    pub fn symbol_name(&self, tcx: TyCtxt<'tcx>) -> SymbolName {
         match *self {
             MonoItem::Fn(instance) => tcx.symbol_name(instance),
             MonoItem::Static(def_id) => {
@@ -87,7 +87,7 @@ impl<'tcx> MonoItem<'tcx> {
         }
     }
 
-    pub fn instantiation_mode(&self, tcx: TyCtxt<'tcx, 'tcx>) -> InstantiationMode {
+    pub fn instantiation_mode(&self, tcx: TyCtxt<'tcx>) -> InstantiationMode {
         let inline_in_all_cgus =
             tcx.sess.opts.debugging_opts.inline_in_all_cgus.unwrap_or_else(|| {
                 tcx.sess.opts.optimize != OptLevel::No
@@ -131,7 +131,7 @@ impl<'tcx> MonoItem<'tcx> {
         }
     }
 
-    pub fn explicit_linkage(&self, tcx: TyCtxt<'tcx, 'tcx>) -> Option<Linkage> {
+    pub fn explicit_linkage(&self, tcx: TyCtxt<'tcx>) -> Option<Linkage> {
         let def_id = match *self {
             MonoItem::Fn(ref instance) => instance.def_id(),
             MonoItem::Static(def_id) => def_id,
@@ -167,7 +167,7 @@ impl<'tcx> MonoItem<'tcx> {
     /// Similarly, if a vtable method has such a signature, and therefore can't
     /// be used, we can just not emit it and have a placeholder (a null pointer,
     /// which will never be accessed) in its place.
-    pub fn is_instantiable(&self, tcx: TyCtxt<'tcx, 'tcx>) -> bool {
+    pub fn is_instantiable(&self, tcx: TyCtxt<'tcx>) -> bool {
         debug!("is_instantiable({:?})", self);
         let (def_id, substs) = match *self {
             MonoItem::Fn(ref instance) => (instance.def_id(), instance.substs),
@@ -179,7 +179,7 @@ impl<'tcx> MonoItem<'tcx> {
         tcx.substitute_normalize_and_test_predicates((def_id, &substs))
     }
 
-    pub fn to_string(&self, tcx: TyCtxt<'tcx, 'tcx>, debug: bool) -> String {
+    pub fn to_string(&self, tcx: TyCtxt<'tcx>, debug: bool) -> String {
         return match *self {
             MonoItem::Fn(instance) => {
                 to_string_internal(tcx, "fn ", instance, debug)
@@ -194,7 +194,7 @@ impl<'tcx> MonoItem<'tcx> {
         };
 
         fn to_string_internal<'tcx>(
-            tcx: TyCtxt<'tcx, 'tcx>,
+            tcx: TyCtxt<'tcx>,
             prefix: &str,
             instance: Instance<'tcx>,
             debug: bool,
@@ -207,7 +207,7 @@ impl<'tcx> MonoItem<'tcx> {
         }
     }
 
-    pub fn local_span(&self, tcx: TyCtxt<'tcx, 'tcx>) -> Option<Span> {
+    pub fn local_span(&self, tcx: TyCtxt<'tcx>) -> Option<Span> {
         match *self {
             MonoItem::Fn(Instance { def, .. }) => {
                 tcx.hir().as_local_hir_id(def.def_id())
@@ -333,7 +333,7 @@ impl<'tcx> CodegenUnit<'tcx> {
         base_n::encode(hash, base_n::CASE_INSENSITIVE)
     }
 
-    pub fn estimate_size(&mut self, tcx: TyCtxt<'tcx, 'tcx>) {
+    pub fn estimate_size(&mut self, tcx: TyCtxt<'tcx>) {
         // Estimate the size of a codegen unit as (approximately) the number of MIR
         // statements it corresponds to.
         self.size_estimate = Some(self.items.keys().map(|mi| mi.size_estimate(tcx)).sum());
@@ -359,7 +359,7 @@ impl<'tcx> CodegenUnit<'tcx> {
         WorkProductId::from_cgu_name(&self.name().as_str())
     }
 
-    pub fn work_product(&self, tcx: TyCtxt<'_, '_>) -> WorkProduct {
+    pub fn work_product(&self, tcx: TyCtxt<'_>) -> WorkProduct {
         let work_product_id = self.work_product_id();
         tcx.dep_graph
            .previous_work_product(&work_product_id)
@@ -370,14 +370,14 @@ impl<'tcx> CodegenUnit<'tcx> {
 
     pub fn items_in_deterministic_order(
         &self,
-        tcx: TyCtxt<'tcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
     ) -> Vec<(MonoItem<'tcx>, (Linkage, Visibility))> {
         // The codegen tests rely on items being process in the same order as
         // they appear in the file, so for local items, we sort by node_id first
         #[derive(PartialEq, Eq, PartialOrd, Ord)]
         pub struct ItemSortKey(Option<HirId>, SymbolName);
 
-        fn item_sort_key<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, item: MonoItem<'tcx>) -> ItemSortKey {
+        fn item_sort_key<'tcx>(tcx: TyCtxt<'tcx>, item: MonoItem<'tcx>) -> ItemSortKey {
             ItemSortKey(match item {
                 MonoItem::Fn(ref instance) => {
                     match instance.def {
@@ -413,7 +413,7 @@ impl<'tcx> CodegenUnit<'tcx> {
         items
     }
 
-    pub fn codegen_dep_node(&self, tcx: TyCtxt<'tcx, 'tcx>) -> DepNode {
+    pub fn codegen_dep_node(&self, tcx: TyCtxt<'tcx>) -> DepNode {
         DepNode::new(tcx, DepConstructor::CompileCodegenUnit(self.name().clone()))
     }
 }
@@ -443,13 +443,13 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for CodegenUnit<'tcx> {
     }
 }
 
-pub struct CodegenUnitNameBuilder<'gcx, 'tcx> {
-    tcx: TyCtxt<'gcx, 'tcx>,
+pub struct CodegenUnitNameBuilder<'tcx> {
+    tcx: TyCtxt<'tcx>,
     cache: FxHashMap<CrateNum, String>,
 }
 
-impl CodegenUnitNameBuilder<'gcx, 'tcx> {
-    pub fn new(tcx: TyCtxt<'gcx, 'tcx>) -> Self {
+impl CodegenUnitNameBuilder<'tcx> {
+    pub fn new(tcx: TyCtxt<'tcx>) -> Self {
         CodegenUnitNameBuilder {
             tcx,
             cache: Default::default(),

src/librustc/mir/tcx.rs

@@ -21,7 +21,7 @@ pub struct PlaceTy<'tcx> {
 #[cfg(target_arch = "x86_64")]
 static_assert_size!(PlaceTy<'_>, 16);
 
-impl<'gcx, 'tcx> PlaceTy<'tcx> {
+impl<'tcx> PlaceTy<'tcx> {
     pub fn from_ty(ty: Ty<'tcx>) -> PlaceTy<'tcx> {
         PlaceTy { ty, variant_index: None }
     }
@@ -33,7 +33,7 @@ impl<'gcx, 'tcx> PlaceTy<'tcx> {
     /// not carry a `Ty` for `T`.)
     ///
     /// Note that the resulting type has not been normalized.
-    pub fn field_ty(self, tcx: TyCtxt<'gcx, 'tcx>, f: &Field) -> Ty<'tcx> {
+    pub fn field_ty(self, tcx: TyCtxt<'tcx>, f: &Field) -> Ty<'tcx> {
         let answer = match self.ty.sty {
             ty::Adt(adt_def, substs) => {
                 let variant_def = match self.variant_index {
@@ -56,7 +56,7 @@ impl<'gcx, 'tcx> PlaceTy<'tcx> {
     /// Convenience wrapper around `projection_ty_core` for
     /// `PlaceElem`, where we can just use the `Ty` that is already
     /// stored inline on field projection elems.
-    pub fn projection_ty(self, tcx: TyCtxt<'gcx, 'tcx>, elem: &PlaceElem<'tcx>) -> PlaceTy<'tcx> {
+    pub fn projection_ty(self, tcx: TyCtxt<'tcx>, elem: &PlaceElem<'tcx>) -> PlaceTy<'tcx> {
         self.projection_ty_core(tcx, elem, |_, _, ty| ty)
     }
 
@@ -67,7 +67,7 @@ impl<'gcx, 'tcx> PlaceTy<'tcx> {
     /// (which should be trivial when `T` = `Ty`).
     pub fn projection_ty_core<V, T>(
         self,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         elem: &ProjectionElem<V, T>,
         mut handle_field: impl FnMut(&Self, &Field, &T) -> Ty<'tcx>,
     ) -> PlaceTy<'tcx>
@@ -118,7 +118,7 @@ BraceStructTypeFoldableImpl! {
 }
 
 impl<'tcx> Place<'tcx> {
-    pub fn ty<'gcx, D>(&self, local_decls: &D, tcx: TyCtxt<'gcx, 'tcx>) -> PlaceTy<'tcx>
+    pub fn ty<D>(&self, local_decls: &D, tcx: TyCtxt<'tcx>) -> PlaceTy<'tcx>
     where
         D: HasLocalDecls<'tcx>,
     {
@@ -139,7 +139,7 @@ pub enum RvalueInitializationState {
 }
 
 impl<'tcx> Rvalue<'tcx> {
-    pub fn ty<'gcx, D>(&self, local_decls: &D, tcx: TyCtxt<'gcx, 'tcx>) -> Ty<'tcx>
+    pub fn ty<D>(&self, local_decls: &D, tcx: TyCtxt<'tcx>) -> Ty<'tcx>
     where
         D: HasLocalDecls<'tcx>,
     {
@@ -221,7 +221,7 @@ impl<'tcx> Rvalue<'tcx> {
 }
 
 impl<'tcx> Operand<'tcx> {
-    pub fn ty<'gcx, D>(&self, local_decls: &D, tcx: TyCtxt<'gcx, 'tcx>) -> Ty<'tcx>
+    pub fn ty<D>(&self, local_decls: &D, tcx: TyCtxt<'tcx>) -> Ty<'tcx>
     where
         D: HasLocalDecls<'tcx>,
     {
@@ -234,9 +234,9 @@ impl<'tcx> Operand<'tcx> {
 }
 
 impl<'tcx> BinOp {
-    pub fn ty<'gcx>(
+    pub fn ty(
         &self,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         lhs_ty: Ty<'tcx>,
         rhs_ty: Ty<'tcx>,
     ) -> Ty<'tcx> {

src/librustc/traits/auto_trait.rs

@@ -48,11 +48,11 @@ pub struct AutoTraitInfo<'cx> {
 }
 
 pub struct AutoTraitFinder<'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
 }
 
 impl<'tcx> AutoTraitFinder<'tcx> {
-    pub fn new(tcx: TyCtxt<'tcx, 'tcx>) -> Self {
+    pub fn new(tcx: TyCtxt<'tcx>) -> Self {
         AutoTraitFinder { tcx }
     }
 
@@ -79,7 +79,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
         ty: Ty<'tcx>,
         orig_env: ty::ParamEnv<'tcx>,
         trait_did: DefId,
-        auto_trait_callback: impl for<'i> Fn(&InferCtxt<'_, 'tcx, 'i>, AutoTraitInfo<'i>) -> A,
+        auto_trait_callback: impl Fn(&InferCtxt<'_, 'tcx>, AutoTraitInfo<'tcx>) -> A,
     ) -> AutoTraitResult<A> {
         let tcx = self.tcx;
 
@@ -270,16 +270,16 @@ impl AutoTraitFinder<'tcx> {
     // the final synthesized generics: we don't want our generated docs page to contain something
     // like 'T: Copy + Clone', as that's redundant. Therefore, we keep track of a separate
     // 'user_env', which only holds the predicates that will actually be displayed to the user.
-    fn evaluate_predicates<'b, 'c>(
+    fn evaluate_predicates(
         &self,
-        infcx: &InferCtxt<'b, 'tcx, 'c>,
+        infcx: &InferCtxt<'_, 'tcx>,
         trait_did: DefId,
-        ty: Ty<'c>,
-        param_env: ty::ParamEnv<'c>,
-        user_env: ty::ParamEnv<'c>,
-        fresh_preds: &mut FxHashSet<ty::Predicate<'c>>,
+        ty: Ty<'tcx>,
+        param_env: ty::ParamEnv<'tcx>,
+        user_env: ty::ParamEnv<'tcx>,
+        fresh_preds: &mut FxHashSet<ty::Predicate<'tcx>>,
         only_projections: bool,
-    ) -> Option<(ty::ParamEnv<'c>, ty::ParamEnv<'c>)> {
+    ) -> Option<(ty::ParamEnv<'tcx>, ty::ParamEnv<'tcx>)> {
         let tcx = infcx.tcx;
 
         let mut select = SelectionContext::with_negative(&infcx, true);
@@ -617,20 +617,14 @@ impl AutoTraitFinder<'tcx> {
         }
     }
 
-    fn evaluate_nested_obligations<
-        'b,
-        'c,
-        'd,
-        'cx,
-        T: Iterator<Item = Obligation<'cx, ty::Predicate<'cx>>>,
-    >(
+    fn evaluate_nested_obligations(
         &self,
         ty: Ty<'_>,
-        nested: T,
-        computed_preds: &'b mut FxHashSet<ty::Predicate<'cx>>,
-        fresh_preds: &'b mut FxHashSet<ty::Predicate<'cx>>,
-        predicates: &'b mut VecDeque<ty::PolyTraitPredicate<'cx>>,
-        select: &mut SelectionContext<'c, 'd, 'cx>,
+        nested: impl Iterator<Item = Obligation<'tcx, ty::Predicate<'tcx>>>,
+        computed_preds: &mut FxHashSet<ty::Predicate<'tcx>>,
+        fresh_preds: &mut FxHashSet<ty::Predicate<'tcx>>,
+        predicates: &mut VecDeque<ty::PolyTraitPredicate<'tcx>>,
+        select: &mut SelectionContext<'_, 'tcx>,
         only_projections: bool,
     ) -> bool {
         let dummy_cause = ObligationCause::misc(DUMMY_SP, hir::DUMMY_HIR_ID);
@@ -822,23 +816,23 @@ impl AutoTraitFinder<'tcx> {
         return true;
     }
 
-    pub fn clean_pred<'c, 'd, 'cx>(
+    pub fn clean_pred(
         &self,
-        infcx: &InferCtxt<'c, 'd, 'cx>,
-        p: ty::Predicate<'cx>,
-    ) -> ty::Predicate<'cx> {
+        infcx: &InferCtxt<'_, 'tcx>,
+        p: ty::Predicate<'tcx>,
+    ) -> ty::Predicate<'tcx> {
         infcx.freshen(p)
     }
 }
 
 // Replaces all ReVars in a type with ty::Region's, using the provided map
-pub struct RegionReplacer<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
+pub struct RegionReplacer<'a, 'tcx> {
     vid_to_region: &'a FxHashMap<ty::RegionVid, ty::Region<'tcx>>,
-    tcx: TyCtxt<'gcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
 }
 
-impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for RegionReplacer<'a, 'gcx, 'tcx> {
-    fn tcx<'b>(&'b self) -> TyCtxt<'gcx, 'tcx> {
+impl<'a, 'tcx> TypeFolder<'tcx> for RegionReplacer<'a, 'tcx> {
+    fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
         self.tcx
     }
 

src/librustc/traits/chalk_fulfill.rs

@@ -29,7 +29,7 @@ impl FulfillmentContext<'tcx> {
 }
 
 fn in_environment(
-    infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+    infcx: &InferCtxt<'_, 'tcx>,
     obligation: PredicateObligation<'tcx>
 ) -> InEnvironment<'tcx, PredicateObligation<'tcx>> {
     assert!(!infcx.is_in_snapshot());
@@ -52,7 +52,7 @@ fn in_environment(
 impl TraitEngine<'tcx> for FulfillmentContext<'tcx> {
     fn normalize_projection_type(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
         _param_env: ty::ParamEnv<'tcx>,
         projection_ty: ty::ProjectionTy<'tcx>,
         _cause: ObligationCause<'tcx>,
@@ -62,7 +62,7 @@ impl TraitEngine<'tcx> for FulfillmentContext<'tcx> {
 
     fn register_predicate_obligation(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
         obligation: PredicateObligation<'tcx>,
     ) {
         self.obligations.insert(in_environment(infcx, obligation));
@@ -70,7 +70,7 @@ impl TraitEngine<'tcx> for FulfillmentContext<'tcx> {
 
     fn select_all_or_error(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
     ) -> Result<(), Vec<FulfillmentError<'tcx>>> {
         self.select_where_possible(infcx)?;
 
@@ -89,7 +89,7 @@ impl TraitEngine<'tcx> for FulfillmentContext<'tcx> {
 
     fn select_where_possible(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
     ) -> Result<(), Vec<FulfillmentError<'tcx>>> {
         let mut errors = Vec::new();
         let mut next_round = FxHashSet::default();

src/librustc/traits/codegen/mod.rs

@@ -19,7 +19,7 @@ use crate::ty::fold::TypeFoldable;
 /// obligations *could be* resolved if we wanted to.
 /// Assumes that this is run after the entire crate has been successfully type-checked.
 pub fn codegen_fulfill_obligation<'tcx>(
-    ty: TyCtxt<'tcx, 'tcx>,
+    ty: TyCtxt<'tcx>,
     (param_env, trait_ref): (ty::ParamEnv<'tcx>, ty::PolyTraitRef<'tcx>),
 ) -> Vtable<'tcx, ()> {
     // Remove any references to regions; this helps improve caching.
@@ -73,7 +73,7 @@ pub fn codegen_fulfill_obligation<'tcx>(
     })
 }
 
-impl<'tcx> TyCtxt<'tcx, 'tcx> {
+impl<'tcx> TyCtxt<'tcx> {
     /// Monomorphizes a type from the AST by first applying the
     /// in-scope substitutions and then normalizing any associated
     /// types.
@@ -115,19 +115,19 @@ impl<'tcx> DepTrackingMapConfig for TraitSelectionCache<'tcx> {
 
 // # Global Cache
 
-pub struct ProjectionCache<'gcx> {
-    data: PhantomData<&'gcx ()>
+pub struct ProjectionCache<'tcx> {
+    data: PhantomData<&'tcx ()>
 }
 
-impl<'gcx> DepTrackingMapConfig for ProjectionCache<'gcx> {
-    type Key = Ty<'gcx>;
-    type Value = Ty<'gcx>;
+impl<'tcx> DepTrackingMapConfig for ProjectionCache<'tcx> {
+    type Key = Ty<'tcx>;
+    type Value = Ty<'tcx>;
     fn to_dep_kind() -> DepKind {
         DepKind::TraitSelect
     }
 }
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     /// Finishes processes any obligations that remain in the
     /// fulfillment context, and then returns the result with all type
     /// variables removed and regions erased. Because this is intended
@@ -141,7 +141,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                                         fulfill_cx: &mut FulfillmentContext<'tcx>,
                                         result: &T)
                                         -> T::Lifted
-        where T: TypeFoldable<'tcx> + ty::Lift<'gcx>
+        where T: TypeFoldable<'tcx> + ty::Lift<'tcx>
     {
         debug!("drain_fulfillment_cx_or_panic()");
 

src/librustc/traits/coherence.rs

@@ -48,8 +48,8 @@ pub fn add_placeholder_note(err: &mut errors::DiagnosticBuilder<'_>) {
 /// If there are types that satisfy both impls, invokes `on_overlap`
 /// with a suitably-freshened `ImplHeader` with those types
 /// substituted. Otherwise, invokes `no_overlap`.
-pub fn overlapping_impls<'gcx, F1, F2, R>(
-    tcx: TyCtxt<'gcx, 'gcx>,
+pub fn overlapping_impls<'tcx, F1, F2, R>(
+    tcx: TyCtxt<'tcx>,
     impl1_def_id: DefId,
     impl2_def_id: DefId,
     intercrate_mode: IntercrateMode,
@@ -87,7 +87,7 @@ where
     })
 }
 
-fn with_fresh_ty_vars<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn with_fresh_ty_vars<'cx, 'tcx>(selcx: &mut SelectionContext<'cx, 'tcx>,
                                        param_env: ty::ParamEnv<'tcx>,
                                        impl_def_id: DefId)
                                        -> ty::ImplHeader<'tcx>
@@ -111,8 +111,8 @@ fn with_fresh_ty_vars<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, '
 
 /// Can both impl `a` and impl `b` be satisfied by a common type (including
 /// where-clauses)? If so, returns an `ImplHeader` that unifies the two impls.
-fn overlap<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn overlap<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     a_def_id: DefId,
     b_def_id: DefId,
 ) -> Option<OverlapResult<'tcx>> {
@@ -122,7 +122,7 @@ fn overlap<'cx, 'gcx, 'tcx>(
 }
 
 fn overlap_within_probe(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     a_def_id: DefId,
     b_def_id: DefId,
     snapshot: &CombinedSnapshot<'_, 'tcx>,
@@ -183,8 +183,8 @@ fn overlap_within_probe(
     Some(OverlapResult { impl_header, intercrate_ambiguity_causes, involves_placeholder })
 }
 
-pub fn trait_ref_is_knowable<'gcx, 'tcx>(
-    tcx: TyCtxt<'gcx, 'tcx>,
+pub fn trait_ref_is_knowable<'tcx>(
+    tcx: TyCtxt<'tcx>,
     trait_ref: ty::TraitRef<'tcx>,
 ) -> Option<Conflict> {
     debug!("trait_ref_is_knowable(trait_ref={:?})", trait_ref);
@@ -229,8 +229,8 @@ pub fn trait_ref_is_knowable<'gcx, 'tcx>(
     }
 }
 
-pub fn trait_ref_is_local_or_fundamental<'gcx, 'tcx>(
-    tcx: TyCtxt<'gcx, 'tcx>,
+pub fn trait_ref_is_local_or_fundamental<'tcx>(
+    tcx: TyCtxt<'tcx>,
     trait_ref: ty::TraitRef<'tcx>,
 ) -> bool {
     trait_ref.def_id.krate == LOCAL_CRATE || tcx.has_attr(trait_ref.def_id, sym::fundamental)
@@ -247,8 +247,8 @@ pub enum OrphanCheckErr<'tcx> {
 ///
 /// 1. All type parameters in `Self` must be "covered" by some local type constructor.
 /// 2. Some local type must appear in `Self`.
-pub fn orphan_check<'gcx, 'tcx>(
-    tcx: TyCtxt<'gcx, 'tcx>,
+pub fn orphan_check<'tcx>(
+    tcx: TyCtxt<'tcx>,
     impl_def_id: DefId,
 ) -> Result<(), OrphanCheckErr<'tcx>> {
     debug!("orphan_check({:?})", impl_def_id);
@@ -355,7 +355,7 @@ pub fn orphan_check<'gcx, 'tcx>(
 /// Note that this function is never called for types that have both type
 /// parameters and inference variables.
 fn orphan_check_trait_ref<'tcx>(
-    tcx: TyCtxt<'_, '_>,
+    tcx: TyCtxt<'_>,
     trait_ref: ty::TraitRef<'tcx>,
     in_crate: InCrate,
 ) -> Result<(), OrphanCheckErr<'tcx>> {
@@ -431,7 +431,7 @@ fn orphan_check_trait_ref<'tcx>(
     }
 }
 
-fn uncovered_tys<'tcx>(tcx: TyCtxt<'_, '_>, ty: Ty<'tcx>, in_crate: InCrate) -> Vec<Ty<'tcx>> {
+fn uncovered_tys<'tcx>(tcx: TyCtxt<'_>, ty: Ty<'tcx>, in_crate: InCrate) -> Vec<Ty<'tcx>> {
     if ty_is_local_constructor(ty, in_crate) {
         vec![]
     } else if fundamental_ty(ty) {
@@ -450,7 +450,7 @@ fn is_possibly_remote_type(ty: Ty<'_>, _in_crate: InCrate) -> bool {
     }
 }
 
-fn ty_is_local(tcx: TyCtxt<'_, '_>, ty: Ty<'_>, in_crate: InCrate) -> bool {
+fn ty_is_local(tcx: TyCtxt<'_>, ty: Ty<'_>, in_crate: InCrate) -> bool {
     ty_is_local_constructor(ty, in_crate) ||
         fundamental_ty(ty) && ty.walk_shallow().any(|t| ty_is_local(tcx, t, in_crate))
 }

src/librustc/traits/engine.rs

@@ -9,7 +9,7 @@ use super::{ObligationCause, PredicateObligation};
 pub trait TraitEngine<'tcx>: 'tcx {
     fn normalize_projection_type(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
         param_env: ty::ParamEnv<'tcx>,
         projection_ty: ty::ProjectionTy<'tcx>,
         cause: ObligationCause<'tcx>,
@@ -20,7 +20,7 @@ pub trait TraitEngine<'tcx>: 'tcx {
     /// parameters (except for `Self`).
     fn register_bound(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
         param_env: ty::ParamEnv<'tcx>,
         ty: Ty<'tcx>,
         def_id: DefId,
@@ -40,18 +40,18 @@ pub trait TraitEngine<'tcx>: 'tcx {
 
     fn register_predicate_obligation(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
         obligation: PredicateObligation<'tcx>,
     );
 
     fn select_all_or_error(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
     ) -> Result<(), Vec<FulfillmentError<'tcx>>>;
 
     fn select_where_possible(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
     ) -> Result<(), Vec<FulfillmentError<'tcx>>>;
 
     fn pending_obligations(&self) -> Vec<PredicateObligation<'tcx>>;
@@ -60,7 +60,7 @@ pub trait TraitEngine<'tcx>: 'tcx {
 pub trait TraitEngineExt<'tcx> {
     fn register_predicate_obligations(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
         obligations: impl IntoIterator<Item = PredicateObligation<'tcx>>,
     );
 }
@@ -68,7 +68,7 @@ pub trait TraitEngineExt<'tcx> {
 impl<T: ?Sized + TraitEngine<'tcx>> TraitEngineExt<'tcx> for T {
     fn register_predicate_obligations(
         &mut self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
         obligations: impl IntoIterator<Item = PredicateObligation<'tcx>>,
     ) {
         for obligation in obligations {
@@ -78,7 +78,7 @@ impl<T: ?Sized + TraitEngine<'tcx>> TraitEngineExt<'tcx> for T {
 }
 
 impl dyn TraitEngine<'tcx> {
-    pub fn new(tcx: TyCtxt<'_, 'tcx>) -> Box<Self> {
+    pub fn new(tcx: TyCtxt<'tcx>) -> Box<Self> {
         if tcx.sess.opts.debugging_opts.chalk {
             Box::new(ChalkFulfillmentContext::new())
         } else {

src/librustc/traits/error_reporting.rs

@@ -38,7 +38,7 @@ use syntax::ast;
 use syntax::symbol::sym;
 use syntax_pos::{DUMMY_SP, Span, ExpnInfo, ExpnFormat};
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn report_fulfillment_errors(&self,
                                      errors: &[FulfillmentError<'tcx>],
                                      body_id: Option<hir::BodyId>,
@@ -1249,8 +1249,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         expected_ref: ty::PolyTraitRef<'tcx>,
         found: ty::PolyTraitRef<'tcx>,
     ) -> DiagnosticBuilder<'tcx> {
-        fn build_fn_sig_string<'gcx, 'tcx>(
-            tcx: TyCtxt<'gcx, 'tcx>,
+        fn build_fn_sig_string<'tcx>(
+            tcx: TyCtxt<'tcx>,
             trait_ref: &ty::TraitRef<'tcx>,
         ) -> String {
             let inputs = trait_ref.substs.type_at(1);
@@ -1296,7 +1296,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     }
 }
 
-impl<'gcx, 'tcx> TyCtxt<'gcx, 'tcx> {
+impl<'tcx> TyCtxt<'tcx> {
     pub fn recursive_type_with_infinite_size_error(self,
                                                    type_def_id: DefId)
                                                    -> DiagnosticBuilder<'tcx>
@@ -1342,7 +1342,7 @@ impl<'gcx, 'tcx> TyCtxt<'gcx, 'tcx> {
     }
 }
 
-impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
+impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     fn maybe_report_ambiguity(&self, obligation: &PredicateObligation<'tcx>,
                               body_id: Option<hir::BodyId>) {
         // Unable to successfully determine, probably means
@@ -1454,13 +1454,13 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         pred: ty::PolyTraitRef<'tcx>,
     ) -> bool {
-        struct ParamToVarFolder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
-            infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+        struct ParamToVarFolder<'a, 'tcx: 'a> {
+            infcx: &'a InferCtxt<'a, 'tcx>,
             var_map: FxHashMap<Ty<'tcx>, Ty<'tcx>>
         }
 
-        impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for ParamToVarFolder<'a, 'gcx, 'tcx> {
-            fn tcx<'b>(&'b self) -> TyCtxt<'gcx, 'tcx> { self.infcx.tcx }
+        impl<'a, 'tcx> TypeFolder<'tcx> for ParamToVarFolder<'a, 'tcx> {
+            fn tcx<'b>(&'b self) -> TyCtxt<'tcx> { self.infcx.tcx }
 
             fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
                 if let ty::Param(ty::ParamTy {name, .. }) = ty.sty {

src/librustc/traits/fulfill.rs

@@ -68,7 +68,7 @@ pub struct PendingPredicateObligation<'tcx> {
     pub stalled_on: Vec<Ty<'tcx>>,
 }
 
-impl<'a, 'gcx, 'tcx> FulfillmentContext<'tcx> {
+impl<'a, 'tcx> FulfillmentContext<'tcx> {
     /// Creates a new fulfillment context.
     pub fn new() -> FulfillmentContext<'tcx> {
         FulfillmentContext {
@@ -95,7 +95,7 @@ impl<'a, 'gcx, 'tcx> FulfillmentContext<'tcx> {
     }
 
     /// Attempts to select obligations using `selcx`.
-    fn select(&mut self, selcx: &mut SelectionContext<'a, 'gcx, 'tcx>)
+    fn select(&mut self, selcx: &mut SelectionContext<'a, 'tcx>)
               -> Result<(), Vec<FulfillmentError<'tcx>>> {
         debug!("select(obligation-forest-size={})", self.predicates.len());
 
@@ -143,8 +143,8 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> {
     /// `SomeTrait` or a where-clause that lets us unify `$0` with
     /// something concrete. If this fails, we'll unify `$0` with
     /// `projection_ty` again.
-    fn normalize_projection_type<'a, 'gcx>(&mut self,
-                                 infcx: &InferCtxt<'a, 'gcx, 'tcx>,
+    fn normalize_projection_type(&mut self,
+                                 infcx: &InferCtxt<'_, 'tcx>,
                                  param_env: ty::ParamEnv<'tcx>,
                                  projection_ty: ty::ProjectionTy<'tcx>,
                                  cause: ObligationCause<'tcx>)
@@ -172,8 +172,8 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> {
         normalized_ty
     }
 
-    fn register_predicate_obligation<'a, 'gcx>(&mut self,
-                                     infcx: &InferCtxt<'a, 'gcx, 'tcx>,
+    fn register_predicate_obligation(&mut self,
+                                     infcx: &InferCtxt<'_, 'tcx>,
                                      obligation: PredicateObligation<'tcx>)
     {
         // this helps to reduce duplicate errors, as well as making
@@ -190,9 +190,9 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> {
         });
     }
 
-    fn select_all_or_error<'a, 'gcx>(
+    fn select_all_or_error(
         &mut self,
-        infcx: &InferCtxt<'a, 'gcx, 'tcx>
+        infcx: &InferCtxt<'_, 'tcx>
     ) -> Result<(),Vec<FulfillmentError<'tcx>>>
     {
         self.select_where_possible(infcx)?;
@@ -209,8 +209,8 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> {
         }
     }
 
-    fn select_where_possible<'a, 'gcx>(&mut self,
-                             infcx: &InferCtxt<'a, 'gcx, 'tcx>)
+    fn select_where_possible(&mut self,
+                             infcx: &InferCtxt<'_, 'tcx>)
                              -> Result<(),Vec<FulfillmentError<'tcx>>>
     {
         let mut selcx = SelectionContext::new(infcx);
@@ -222,8 +222,8 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> {
     }
 }
 
-struct FulfillProcessor<'a, 'b: 'a, 'gcx: 'tcx, 'tcx: 'b> {
-    selcx: &'a mut SelectionContext<'b, 'gcx, 'tcx>,
+struct FulfillProcessor<'a, 'b: 'a, 'tcx: 'b> {
+    selcx: &'a mut SelectionContext<'b, 'tcx>,
     register_region_obligations: bool
 }
 
@@ -234,7 +234,7 @@ fn mk_pending(os: Vec<PredicateObligation<'tcx>>) -> Vec<PendingPredicateObligat
     }).collect()
 }
 
-impl<'a, 'b, 'gcx, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'gcx, 'tcx> {
+impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> {
     type Obligation = PendingPredicateObligation<'tcx>;
     type Error = FulfillmentErrorCode<'tcx>;
 
@@ -514,7 +514,7 @@ impl<'a, 'b, 'gcx, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'gcx,
 }
 
 /// Returns the set of type variables contained in a trait ref
-fn trait_ref_type_vars<'a, 'gcx, 'tcx>(selcx: &mut SelectionContext<'a, 'gcx, 'tcx>,
+fn trait_ref_type_vars<'a, 'tcx>(selcx: &mut SelectionContext<'a, 'tcx>,
                                        t: ty::PolyTraitRef<'tcx>) -> Vec<Ty<'tcx>>
 {
     t.skip_binder() // ok b/c this check doesn't care about regions

src/librustc/traits/mod.rs

@@ -140,7 +140,7 @@ pub struct ObligationCause<'tcx> {
 }
 
 impl<'tcx> ObligationCause<'tcx> {
-    pub fn span<'gcx>(&self, tcx: TyCtxt<'gcx, 'tcx>) -> Span {
+    pub fn span(&self, tcx: TyCtxt<'tcx>) -> Span {
         match self.code {
             ObligationCauseCode::CompareImplMethodObligation { .. } |
             ObligationCauseCode::MainFunctionType |
@@ -363,9 +363,9 @@ impl<'tcx> DomainGoal<'tcx> {
 }
 
 impl<'tcx> GoalKind<'tcx> {
-    pub fn from_poly_domain_goal<'gcx>(
+    pub fn from_poly_domain_goal(
         domain_goal: PolyDomainGoal<'tcx>,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
     ) -> GoalKind<'tcx> {
         match domain_goal.no_bound_vars() {
             Some(p) => p.into_goal(),
@@ -643,8 +643,8 @@ pub fn predicates_for_generics<'tcx>(cause: ObligationCause<'tcx>,
 /// `bound` or is not known to meet bound (note that this is
 /// conservative towards *no impl*, which is the opposite of the
 /// `evaluate` methods).
-pub fn type_known_to_meet_bound_modulo_regions<'a, 'gcx, 'tcx>(
-    infcx: &InferCtxt<'a, 'gcx, 'tcx>,
+pub fn type_known_to_meet_bound_modulo_regions<'a, 'tcx>(
+    infcx: &InferCtxt<'a, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     ty: Ty<'tcx>,
     def_id: DefId,
@@ -711,7 +711,7 @@ pub fn type_known_to_meet_bound_modulo_regions<'a, 'gcx, 'tcx>(
 }
 
 fn do_normalize_predicates<'tcx>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     region_context: DefId,
     cause: ObligationCause<'tcx>,
     elaborated_env: ty::ParamEnv<'tcx>,
@@ -796,7 +796,7 @@ fn do_normalize_predicates<'tcx>(
 // FIXME: this is gonna need to be removed ...
 /// Normalizes the parameter environment, reporting errors if they occur.
 pub fn normalize_param_env_or_error<'tcx>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     region_context: DefId,
     unnormalized_env: ty::ParamEnv<'tcx>,
     cause: ObligationCause<'tcx>,
@@ -904,8 +904,8 @@ pub fn normalize_param_env_or_error<'tcx>(
     )
 }
 
-pub fn fully_normalize<'a, 'gcx, 'tcx, T>(
-    infcx: &InferCtxt<'a, 'gcx, 'tcx>,
+pub fn fully_normalize<'a, 'tcx, T>(
+    infcx: &InferCtxt<'a, 'tcx>,
     mut fulfill_cx: FulfillmentContext<'tcx>,
     cause: ObligationCause<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
@@ -937,7 +937,7 @@ pub fn fully_normalize<'a, 'gcx, 'tcx, T>(
 /// encountered an error or one of the predicates did not hold. Used
 /// when creating vtables to check for unsatisfiable methods.
 fn normalize_and_test_predicates<'tcx>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     predicates: Vec<ty::Predicate<'tcx>>,
 ) -> bool {
     debug!("normalize_and_test_predicates(predicates={:?})",
@@ -966,7 +966,7 @@ fn normalize_and_test_predicates<'tcx>(
 }
 
 fn substitute_normalize_and_test_predicates<'tcx>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     key: (DefId, SubstsRef<'tcx>),
 ) -> bool {
     debug!("substitute_normalize_and_test_predicates(key={:?})",
@@ -984,7 +984,7 @@ fn substitute_normalize_and_test_predicates<'tcx>(
 /// that come from `trait_ref`, including its supertraits.
 #[inline] // FIXME(#35870): avoid closures being unexported due to `impl Trait`.
 fn vtable_methods<'tcx>(
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     trait_ref: ty::PolyTraitRef<'tcx>,
 ) -> &'tcx [Option<(DefId, SubstsRef<'tcx>)>] {
     debug!("vtable_methods({:?})", trait_ref);
@@ -1185,7 +1185,7 @@ pub trait ExClauseFold<'tcx>
 where
     Self: chalk_engine::context::Context + Clone,
 {
-    fn fold_ex_clause_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(
+    fn fold_ex_clause_with<F: TypeFolder<'tcx>>(
         ex_clause: &chalk_engine::ExClause<Self>,
         folder: &mut F,
     ) -> chalk_engine::ExClause<Self>;
@@ -1204,18 +1204,18 @@ where
     type LiftedDelayedLiteral: Debug + 'tcx;
     type LiftedLiteral: Debug + 'tcx;
 
-    fn lift_ex_clause_to_tcx<'gcx>(
+    fn lift_ex_clause_to_tcx(
         ex_clause: &chalk_engine::ExClause<Self>,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
     ) -> Option<Self::LiftedExClause>;
 
-    fn lift_delayed_literal_to_tcx<'gcx>(
+    fn lift_delayed_literal_to_tcx(
         ex_clause: &chalk_engine::DelayedLiteral<Self>,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
     ) -> Option<Self::LiftedDelayedLiteral>;
 
-    fn lift_literal_to_tcx<'gcx>(
+    fn lift_literal_to_tcx(
         ex_clause: &chalk_engine::Literal<Self>,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
     ) -> Option<Self::LiftedLiteral>;
 }

src/librustc/traits/object_safety.rs

@@ -83,7 +83,7 @@ pub enum MethodViolationCode {
     UndispatchableReceiver,
 }
 
-impl<'tcx> TyCtxt<'tcx, 'tcx> {
+impl<'tcx> TyCtxt<'tcx> {
     /// Returns the object safety violations that affect
     /// astconv -- currently, `Self` in supertraits. This is needed
     /// because `object_safety_violations` can't be used during
@@ -702,6 +702,6 @@ impl<'tcx> TyCtxt<'tcx, 'tcx> {
     }
 }
 
-pub(super) fn is_object_safe_provider<'tcx>(tcx: TyCtxt<'tcx, 'tcx>, trait_def_id: DefId) -> bool {
+pub(super) fn is_object_safe_provider<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId) -> bool {
     tcx.object_safety_violations(trait_def_id).is_empty()
 }

src/librustc/traits/on_unimplemented.rs

@@ -36,7 +36,7 @@ impl OnUnimplementedNote {
 }
 
 fn parse_error(
-    tcx: TyCtxt<'_, '_>,
+    tcx: TyCtxt<'_>,
     span: Span,
     message: &str,
     label: &str,
@@ -52,9 +52,9 @@ fn parse_error(
     ErrorReported
 }
 
-impl<'gcx, 'tcx> OnUnimplementedDirective {
+impl<'tcx> OnUnimplementedDirective {
     fn parse(
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         trait_def_id: DefId,
         items: &[NestedMetaItem],
         span: Span,
@@ -134,7 +134,7 @@ impl<'gcx, 'tcx> OnUnimplementedDirective {
     }
 
     pub fn of_item(
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         trait_def_id: DefId,
         impl_def_id: DefId,
     ) -> Result<Option<Self>, ErrorReported> {
@@ -166,7 +166,7 @@ impl<'gcx, 'tcx> OnUnimplementedDirective {
 
     pub fn evaluate(
         &self,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         trait_ref: ty::TraitRef<'tcx>,
         options: &[(Symbol, Option<String>)],
     ) -> OnUnimplementedNote {
@@ -214,9 +214,9 @@ impl<'gcx, 'tcx> OnUnimplementedDirective {
     }
 }
 
-impl<'gcx, 'tcx> OnUnimplementedFormatString {
+impl<'tcx> OnUnimplementedFormatString {
     fn try_parse(
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         trait_def_id: DefId,
         from: LocalInternedString,
         err_sp: Span,
@@ -228,7 +228,7 @@ impl<'gcx, 'tcx> OnUnimplementedFormatString {
 
     fn verify(
         &self,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         trait_def_id: DefId,
         span: Span,
     ) -> Result<(), ErrorReported> {
@@ -274,7 +274,7 @@ impl<'gcx, 'tcx> OnUnimplementedFormatString {
 
     pub fn format(
         &self,
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         trait_ref: ty::TraitRef<'tcx>,
         options: &FxHashMap<Symbol, String>,
     ) -> String {

src/librustc/traits/project.rs

@@ -183,8 +183,8 @@ impl<'tcx> ProjectionTyCandidateSet<'tcx> {
 ///
 /// If successful, this may result in additional obligations. Also returns
 /// the projection cache key used to track these additional obligations.
-pub fn poly_project_and_unify_type<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+pub fn poly_project_and_unify_type<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &PolyProjectionObligation<'tcx>)
     -> Result<Option<Vec<PredicateObligation<'tcx>>>,
               MismatchedProjectionTypes<'tcx>>
@@ -210,8 +210,8 @@ pub fn poly_project_and_unify_type<'cx, 'gcx, 'tcx>(
 ///     <T as Trait>::U == V
 ///
 /// If successful, this may result in additional obligations.
-fn project_and_unify_type<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn project_and_unify_type<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionObligation<'tcx>)
     -> Result<Option<Vec<PredicateObligation<'tcx>>>,
               MismatchedProjectionTypes<'tcx>>
@@ -253,7 +253,7 @@ fn project_and_unify_type<'cx, 'gcx, 'tcx>(
 /// them with a fully resolved type where possible. The return value
 /// combines the normalized result and any additional obligations that
 /// were incurred as result.
-pub fn normalize<'a, 'b, 'gcx, 'tcx, T>(selcx: &'a mut SelectionContext<'b, 'gcx, 'tcx>,
+pub fn normalize<'a, 'b, 'tcx, T>(selcx: &'a mut SelectionContext<'b, 'tcx>,
                                         param_env: ty::ParamEnv<'tcx>,
                                         cause: ObligationCause<'tcx>,
                                         value: &T)
@@ -264,8 +264,8 @@ pub fn normalize<'a, 'b, 'gcx, 'tcx, T>(selcx: &'a mut SelectionContext<'b, 'gcx
 }
 
 /// As `normalize`, but with a custom depth.
-pub fn normalize_with_depth<'a, 'b, 'gcx, 'tcx, T>(
-    selcx: &'a mut SelectionContext<'b, 'gcx, 'tcx>,
+pub fn normalize_with_depth<'a, 'b, 'tcx, T>(
+    selcx: &'a mut SelectionContext<'b, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     cause: ObligationCause<'tcx>,
     depth: usize,
@@ -287,20 +287,20 @@ pub fn normalize_with_depth<'a, 'b, 'gcx, 'tcx, T>(
     }
 }
 
-struct AssocTypeNormalizer<'a, 'b: 'a, 'gcx: 'b+'tcx, 'tcx: 'b> {
-    selcx: &'a mut SelectionContext<'b, 'gcx, 'tcx>,
+struct AssocTypeNormalizer<'a, 'b: 'a, 'tcx: 'b> {
+    selcx: &'a mut SelectionContext<'b, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     cause: ObligationCause<'tcx>,
     obligations: Vec<PredicateObligation<'tcx>>,
     depth: usize,
 }
 
-impl<'a, 'b, 'gcx, 'tcx> AssocTypeNormalizer<'a, 'b, 'gcx, 'tcx> {
-    fn new(selcx: &'a mut SelectionContext<'b, 'gcx, 'tcx>,
+impl<'a, 'b, 'tcx> AssocTypeNormalizer<'a, 'b, 'tcx> {
+    fn new(selcx: &'a mut SelectionContext<'b, 'tcx>,
            param_env: ty::ParamEnv<'tcx>,
            cause: ObligationCause<'tcx>,
            depth: usize)
-           -> AssocTypeNormalizer<'a, 'b, 'gcx, 'tcx>
+           -> AssocTypeNormalizer<'a, 'b, 'tcx>
     {
         AssocTypeNormalizer {
             selcx,
@@ -322,8 +322,8 @@ impl<'a, 'b, 'gcx, 'tcx> AssocTypeNormalizer<'a, 'b, 'gcx, 'tcx> {
     }
 }
 
-impl<'a, 'b, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for AssocTypeNormalizer<'a, 'b, 'gcx, 'tcx> {
-    fn tcx<'c>(&'c self) -> TyCtxt<'gcx, 'tcx> {
+impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
+    fn tcx<'c>(&'c self) -> TyCtxt<'tcx> {
         self.selcx.tcx()
     }
 
@@ -456,8 +456,8 @@ impl<'tcx,T> Normalized<'tcx,T> {
 /// there are unresolved type variables in the projection, we will
 /// substitute a fresh type variable `$X` and generate a new
 /// obligation `<T as Trait>::Item == $X` for later.
-pub fn normalize_projection_type<'a, 'b, 'gcx, 'tcx>(
-    selcx: &'a mut SelectionContext<'b, 'gcx, 'tcx>,
+pub fn normalize_projection_type<'a, 'b, 'tcx>(
+    selcx: &'a mut SelectionContext<'b, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     projection_ty: ty::ProjectionTy<'tcx>,
     cause: ObligationCause<'tcx>,
@@ -501,8 +501,8 @@ pub fn normalize_projection_type<'a, 'b, 'gcx, 'tcx>(
 /// often immediately appended to another obligations vector. So now this
 /// function takes an obligations vector and appends to it directly, which is
 /// slightly uglier but avoids the need for an extra short-lived allocation.
-fn opt_normalize_projection_type<'a, 'b, 'gcx, 'tcx>(
-    selcx: &'a mut SelectionContext<'b, 'gcx, 'tcx>,
+fn opt_normalize_projection_type<'a, 'b, 'tcx>(
+    selcx: &'a mut SelectionContext<'b, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     projection_ty: ty::ProjectionTy<'tcx>,
     cause: ObligationCause<'tcx>,
@@ -705,7 +705,7 @@ fn opt_normalize_projection_type<'a, 'b, 'gcx, 'tcx>(
 /// If there are unresolved type variables, then we need to include
 /// any subobligations that bind them, at least until those type
 /// variables are fully resolved.
-fn prune_cache_value_obligations<'a, 'gcx, 'tcx>(infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+fn prune_cache_value_obligations<'a, 'tcx>(infcx: &'a InferCtxt<'a, 'tcx>,
                                                  result: &NormalizedTy<'tcx>)
                                                  -> NormalizedTy<'tcx> {
     if infcx.unresolved_type_vars(&result.value).is_none() {
@@ -763,8 +763,8 @@ fn prune_cache_value_obligations<'a, 'gcx, 'tcx>(infcx: &'a InferCtxt<'a, 'gcx,
 /// that may yet turn out to be wrong. This *may* lead to some sort
 /// of trouble, though we don't have a concrete example of how that
 /// can occur yet. But it seems risky at best.
-fn get_paranoid_cache_value_obligation<'a, 'gcx, 'tcx>(
-    infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+fn get_paranoid_cache_value_obligation<'a, 'tcx>(
+    infcx: &'a InferCtxt<'a, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     projection_ty: ty::ProjectionTy<'tcx>,
     cause: ObligationCause<'tcx>,
@@ -799,7 +799,7 @@ fn get_paranoid_cache_value_obligation<'a, 'gcx, 'tcx>(
 /// an error for this obligation, but we legitimately should not,
 /// because it contains `[type error]`. Yuck! (See issue #29857 for
 /// one case where this arose.)
-fn normalize_to_error<'a, 'gcx, 'tcx>(selcx: &mut SelectionContext<'a, 'gcx, 'tcx>,
+fn normalize_to_error<'a, 'tcx>(selcx: &mut SelectionContext<'a, 'tcx>,
                                       param_env: ty::ParamEnv<'tcx>,
                                       projection_ty: ty::ProjectionTy<'tcx>,
                                       cause: ObligationCause<'tcx>,
@@ -836,7 +836,7 @@ struct Progress<'tcx> {
 }
 
 impl<'tcx> Progress<'tcx> {
-    fn error<'gcx>(tcx: TyCtxt<'gcx, 'tcx>) -> Self {
+    fn error(tcx: TyCtxt<'tcx>) -> Self {
         Progress {
             ty: tcx.types.err,
             obligations: vec![],
@@ -861,8 +861,8 @@ impl<'tcx> Progress<'tcx> {
 ///
 /// IMPORTANT:
 /// - `obligation` must be fully normalized
-fn project_type<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn project_type<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>)
     -> Result<ProjectedTy<'tcx>, ProjectionTyError<'tcx>>
 {
@@ -925,8 +925,8 @@ fn project_type<'cx, 'gcx, 'tcx>(
 /// The first thing we have to do is scan through the parameter
 /// environment to see whether there are any projection predicates
 /// there that can answer this question.
-fn assemble_candidates_from_param_env<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn assemble_candidates_from_param_env<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     obligation_trait_ref: &ty::TraitRef<'tcx>,
     candidate_set: &mut ProjectionTyCandidateSet<'tcx>)
@@ -950,8 +950,8 @@ fn assemble_candidates_from_param_env<'cx, 'gcx, 'tcx>(
 /// ```
 ///
 /// Here, for example, we could conclude that the result is `i32`.
-fn assemble_candidates_from_trait_def<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn assemble_candidates_from_trait_def<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     obligation_trait_ref: &ty::TraitRef<'tcx>,
     candidate_set: &mut ProjectionTyCandidateSet<'tcx>)
@@ -986,8 +986,8 @@ fn assemble_candidates_from_trait_def<'cx, 'gcx, 'tcx>(
                                         bounds)
 }
 
-fn assemble_candidates_from_predicates<'cx, 'gcx, 'tcx, I>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn assemble_candidates_from_predicates<'cx, 'tcx, I>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     obligation_trait_ref: &ty::TraitRef<'tcx>,
     candidate_set: &mut ProjectionTyCandidateSet<'tcx>,
@@ -1029,8 +1029,8 @@ fn assemble_candidates_from_predicates<'cx, 'gcx, 'tcx, I>(
     }
 }
 
-fn assemble_candidates_from_impls<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn assemble_candidates_from_impls<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     obligation_trait_ref: &ty::TraitRef<'tcx>,
     candidate_set: &mut ProjectionTyCandidateSet<'tcx>)
@@ -1177,8 +1177,8 @@ fn assemble_candidates_from_impls<'cx, 'gcx, 'tcx>(
     });
 }
 
-fn confirm_candidate<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn confirm_candidate<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     obligation_trait_ref: &ty::TraitRef<'tcx>,
     candidate: ProjectionTyCandidate<'tcx>)
@@ -1200,8 +1200,8 @@ fn confirm_candidate<'cx, 'gcx, 'tcx>(
     }
 }
 
-fn confirm_select_candidate<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn confirm_select_candidate<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     obligation_trait_ref: &ty::TraitRef<'tcx>,
     vtable: Selection<'tcx>)
@@ -1230,8 +1230,8 @@ fn confirm_select_candidate<'cx, 'gcx, 'tcx>(
     }
 }
 
-fn confirm_object_candidate<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn confirm_object_candidate<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation:  &ProjectionTyObligation<'tcx>,
     obligation_trait_ref: &ty::TraitRef<'tcx>)
     -> Progress<'tcx>
@@ -1295,8 +1295,8 @@ fn confirm_object_candidate<'cx, 'gcx, 'tcx>(
     confirm_param_env_candidate(selcx, obligation, env_predicate)
 }
 
-fn confirm_generator_candidate<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn confirm_generator_candidate<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     vtable: VtableGeneratorData<'tcx, PredicateObligation<'tcx>>)
     -> Progress<'tcx>
@@ -1348,8 +1348,8 @@ fn confirm_generator_candidate<'cx, 'gcx, 'tcx>(
         .with_addl_obligations(obligations)
 }
 
-fn confirm_fn_pointer_candidate<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn confirm_fn_pointer_candidate<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     fn_pointer_vtable: VtableFnPointerData<'tcx, PredicateObligation<'tcx>>)
     -> Progress<'tcx>
@@ -1370,8 +1370,8 @@ fn confirm_fn_pointer_candidate<'cx, 'gcx, 'tcx>(
         .with_addl_obligations(obligations)
 }
 
-fn confirm_closure_candidate<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn confirm_closure_candidate<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     vtable: VtableClosureData<'tcx, PredicateObligation<'tcx>>)
     -> Progress<'tcx>
@@ -1402,8 +1402,8 @@ fn confirm_closure_candidate<'cx, 'gcx, 'tcx>(
         .with_addl_obligations(obligations)
 }
 
-fn confirm_callable_candidate<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn confirm_callable_candidate<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     fn_sig: ty::PolyFnSig<'tcx>,
     flag: util::TupleArgumentsFlag)
@@ -1437,8 +1437,8 @@ fn confirm_callable_candidate<'cx, 'gcx, 'tcx>(
     confirm_param_env_candidate(selcx, obligation, predicate)
 }
 
-fn confirm_param_env_candidate<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn confirm_param_env_candidate<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     poly_cache_entry: ty::PolyProjectionPredicate<'tcx>,
 ) -> Progress<'tcx> {
@@ -1478,8 +1478,8 @@ fn confirm_param_env_candidate<'cx, 'gcx, 'tcx>(
     }
 }
 
-fn confirm_impl_candidate<'cx, 'gcx, 'tcx>(
-    selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+fn confirm_impl_candidate<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     impl_vtable: VtableImplData<'tcx, PredicateObligation<'tcx>>)
     -> Progress<'tcx>
@@ -1521,8 +1521,8 @@ fn confirm_impl_candidate<'cx, 'gcx, 'tcx>(
 ///
 /// Based on the "projection mode", this lookup may in fact only examine the
 /// topmost impl. See the comments for `Reveal` for more details.
-fn assoc_ty_def<'cx, 'gcx, 'tcx>(
-    selcx: &SelectionContext<'cx, 'gcx, 'tcx>,
+fn assoc_ty_def<'cx, 'tcx>(
+    selcx: &SelectionContext<'cx, 'tcx>,
     impl_def_id: DefId,
     assoc_ty_def_id: DefId)
     -> specialization_graph::NodeItem<ty::AssocItem>
@@ -1608,8 +1608,8 @@ pub struct ProjectionCacheKey<'tcx> {
     ty: ty::ProjectionTy<'tcx>
 }
 
-impl<'cx, 'gcx, 'tcx> ProjectionCacheKey<'tcx> {
-    pub fn from_poly_projection_predicate(selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
+impl<'cx, 'tcx> ProjectionCacheKey<'tcx> {
+    pub fn from_poly_projection_predicate(selcx: &mut SelectionContext<'cx, 'tcx>,
                                           predicate: &ty::PolyProjectionPredicate<'tcx>)
                                           -> Option<Self>
     {

src/librustc/traits/query/dropck_outlives.rs

@@ -6,7 +6,7 @@ use syntax::source_map::Span;
 use crate::ty::subst::Kind;
 use crate::ty::{self, Ty, TyCtxt};
 
-impl<'cx, 'gcx, 'tcx> At<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> At<'cx, 'tcx> {
     /// Given a type `ty` of some value being dropped, computes a set
     /// of "kinds" (types, regions) that must be outlive the execution
     /// of the destructor. These basically correspond to data that the
@@ -85,7 +85,7 @@ pub struct DropckOutlivesResult<'tcx> {
 }
 
 impl<'tcx> DropckOutlivesResult<'tcx> {
-    pub fn report_overflows(&self, tcx: TyCtxt<'_, 'tcx>, span: Span, ty: Ty<'tcx>) {
+    pub fn report_overflows(&self, tcx: TyCtxt<'tcx>, span: Span, ty: Ty<'tcx>) {
         if let Some(overflow_ty) = self.overflows.iter().next() {
             let mut err = struct_span_err!(
                 tcx.sess,
@@ -101,7 +101,7 @@ impl<'tcx> DropckOutlivesResult<'tcx> {
 
     pub fn into_kinds_reporting_overflows(
         self,
-        tcx: TyCtxt<'_, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         span: Span,
         ty: Ty<'tcx>,
     ) -> Vec<Kind<'tcx>> {
@@ -185,7 +185,7 @@ impl_stable_hash_for!(struct DtorckConstraint<'tcx> {
 ///
 /// Note also that `needs_drop` requires a "global" type (i.e., one
 /// with erased regions), but this function does not.
-pub fn trivial_dropck_outlives<'tcx>(tcx: TyCtxt<'_, 'tcx>, ty: Ty<'tcx>) -> bool {
+pub fn trivial_dropck_outlives<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool {
     match ty.sty {
         // None of these types have a destructor and hence they do not
         // require anything in particular to outlive the dtor's

src/librustc/traits/query/evaluate_obligation.rs

@@ -3,7 +3,7 @@ use crate::infer::canonical::OriginalQueryValues;
 use crate::traits::{EvaluationResult, PredicateObligation, SelectionContext,
              TraitQueryMode, OverflowError};
 
-impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// Evaluates whether the predicate can be satisfied (by any means)
     /// in the given `ParamEnv`.
     pub fn predicate_may_hold(

src/librustc/traits/query/normalize.rs

@@ -14,7 +14,7 @@ use crate::ty::{self, Ty, TyCtxt};
 
 use super::NoSolution;
 
-impl<'cx, 'gcx, 'tcx> At<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> At<'cx, 'tcx> {
     /// Normalize `value` in the context of the inference context,
     /// yielding a resulting type, or an error if `value` cannot be
     /// normalized. If you don't care about regions, you should prefer
@@ -73,8 +73,8 @@ pub struct NormalizationResult<'tcx> {
     pub normalized_ty: Ty<'tcx>,
 }
 
-struct QueryNormalizer<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
-    infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
+struct QueryNormalizer<'cx, 'tcx: 'cx> {
+    infcx: &'cx InferCtxt<'cx, 'tcx>,
     cause: &'cx ObligationCause<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     obligations: Vec<PredicateObligation<'tcx>>,
@@ -82,8 +82,8 @@ struct QueryNormalizer<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
     anon_depth: usize,
 }
 
-impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for QueryNormalizer<'cx, 'gcx, 'tcx> {
-    fn tcx<'c>(&'c self) -> TyCtxt<'gcx, 'tcx> {
+impl<'cx, 'tcx> TypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
+    fn tcx<'c>(&'c self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
 

src/librustc/traits/query/normalize_erasing_regions.rs

@@ -10,7 +10,7 @@
 use crate::ty::{self, Ty, TyCtxt};
 use crate::ty::fold::{TypeFoldable, TypeFolder};
 
-impl<'tcx> TyCtxt<'tcx, 'tcx> {
+impl<'tcx> TyCtxt<'tcx> {
     /// Erase the regions in `value` and then fully normalize all the
     /// types found within. The result will also have regions erased.
     ///
@@ -63,12 +63,12 @@ impl<'tcx> TyCtxt<'tcx, 'tcx> {
 }
 
 struct NormalizeAfterErasingRegionsFolder<'tcx> {
-    tcx: TyCtxt<'tcx, 'tcx>,
+    tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
 }
 
-impl TypeFolder<'tcx, 'tcx> for NormalizeAfterErasingRegionsFolder<'tcx> {
-    fn tcx(&self) -> TyCtxt<'tcx, 'tcx> {
+impl TypeFolder<'tcx> for NormalizeAfterErasingRegionsFolder<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
 

src/librustc/traits/query/outlives_bounds.rs

@@ -64,7 +64,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for OutlivesBound<'tcx> {
     }
 }
 
-impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
+impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// Implied bounds are region relationships that we deduce
     /// automatically. The idea is that (e.g.) a caller must check that a
     /// function's argument types are well-formed immediately before

src/librustc/traits/query/type_op/ascribe_user_type.rs

@@ -21,25 +21,25 @@ impl<'tcx> AscribeUserType<'tcx> {
     }
 }
 
-impl<'gcx: 'tcx, 'tcx> super::QueryTypeOp<'gcx, 'tcx> for AscribeUserType<'tcx> {
+impl<'tcx> super::QueryTypeOp<'tcx> for AscribeUserType<'tcx> {
     type QueryResponse = ();
 
     fn try_fast_path(
-        _tcx: TyCtxt<'gcx, 'tcx>,
+        _tcx: TyCtxt<'tcx>,
         _key: &ParamEnvAnd<'tcx, Self>,
     ) -> Option<Self::QueryResponse> {
         None
     }
 
     fn perform_query(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, ()>> {
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Self>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, ()>> {
         tcx.type_op_ascribe_user_type(canonicalized)
     }
 
     fn shrink_to_tcx_lifetime(
-        v: &'a CanonicalizedQueryResponse<'gcx, ()>,
+        v: &'a CanonicalizedQueryResponse<'tcx, ()>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, ()>> {
         v
     }

src/librustc/traits/query/type_op/custom.rs

@@ -14,9 +14,9 @@ pub struct CustomTypeOp<F, G> {
 }
 
 impl<F, G> CustomTypeOp<F, G> {
-    pub fn new<'gcx, 'tcx, R>(closure: F, description: G) -> Self
+    pub fn new<'tcx, R>(closure: F, description: G) -> Self
     where
-        F: FnOnce(&InferCtxt<'_, 'gcx, 'tcx>) -> Fallible<InferOk<'tcx, R>>,
+        F: FnOnce(&InferCtxt<'_, 'tcx>) -> Fallible<InferOk<'tcx, R>>,
         G: Fn() -> String,
     {
         CustomTypeOp {
@@ -26,9 +26,9 @@ impl<F, G> CustomTypeOp<F, G> {
     }
 }
 
-impl<'gcx, 'tcx, F, R, G> super::TypeOp<'gcx, 'tcx> for CustomTypeOp<F, G>
+impl<'tcx, F, R, G> super::TypeOp<'tcx> for CustomTypeOp<F, G>
 where
-    F: for<'a, 'cx> FnOnce(&'a InferCtxt<'cx, 'gcx, 'tcx>) -> Fallible<InferOk<'tcx, R>>,
+    F: for<'a, 'cx> FnOnce(&'a InferCtxt<'cx, 'tcx>) -> Fallible<InferOk<'tcx, R>>,
     G: Fn() -> String,
 {
     type Output = R;
@@ -38,7 +38,7 @@ where
     /// (they will be given over to the NLL region solver).
     fn fully_perform(
         self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
     ) -> Fallible<(Self::Output, Option<Rc<Vec<QueryRegionConstraint<'tcx>>>>)> {
         if cfg!(debug_assertions) {
             info!("fully_perform({:?})", self);
@@ -59,8 +59,8 @@ where
 
 /// Executes `op` and then scrapes out all the "old style" region
 /// constraints that result, creating query-region-constraints.
-fn scrape_region_constraints<'gcx, 'tcx, R>(
-    infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+fn scrape_region_constraints<'tcx, R>(
+    infcx: &InferCtxt<'_, 'tcx>,
     op: impl FnOnce() -> Fallible<InferOk<'tcx, R>>,
 ) -> Fallible<(R, Option<Rc<Vec<QueryRegionConstraint<'tcx>>>>)> {
     let mut fulfill_cx = TraitEngine::new(infcx.tcx);

src/librustc/traits/query/type_op/eq.rs

@@ -14,11 +14,11 @@ impl<'tcx> Eq<'tcx> {
     }
 }
 
-impl<'gcx: 'tcx, 'tcx> super::QueryTypeOp<'gcx, 'tcx> for Eq<'tcx> {
+impl<'tcx> super::QueryTypeOp<'tcx> for Eq<'tcx> {
     type QueryResponse = ();
 
     fn try_fast_path(
-        _tcx: TyCtxt<'gcx, 'tcx>,
+        _tcx: TyCtxt<'tcx>,
         key: &ParamEnvAnd<'tcx, Eq<'tcx>>,
     ) -> Option<Self::QueryResponse> {
         if key.value.a == key.value.b {
@@ -29,14 +29,14 @@ impl<'gcx: 'tcx, 'tcx> super::QueryTypeOp<'gcx, 'tcx> for Eq<'tcx> {
     }
 
     fn perform_query(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, ()>> {
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Self>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, ()>> {
         tcx.type_op_eq(canonicalized)
     }
 
     fn shrink_to_tcx_lifetime(
-        v: &'a CanonicalizedQueryResponse<'gcx, ()>,
+        v: &'a CanonicalizedQueryResponse<'tcx, ()>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, ()>> {
         v
     }

src/librustc/traits/query/type_op/implied_outlives_bounds.rs

@@ -14,20 +14,20 @@ impl<'tcx> ImpliedOutlivesBounds<'tcx> {
     }
 }
 
-impl<'gcx: 'tcx, 'tcx> super::QueryTypeOp<'gcx, 'tcx> for ImpliedOutlivesBounds<'tcx> {
+impl<'tcx> super::QueryTypeOp<'tcx> for ImpliedOutlivesBounds<'tcx> {
     type QueryResponse = Vec<OutlivesBound<'tcx>>;
 
     fn try_fast_path(
-        _tcx: TyCtxt<'gcx, 'tcx>,
+        _tcx: TyCtxt<'tcx>,
         _key: &ParamEnvAnd<'tcx, Self>,
     ) -> Option<Self::QueryResponse> {
         None
     }
 
     fn perform_query(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, Self::QueryResponse>> {
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Self>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self::QueryResponse>> {
         // FIXME this `unchecked_map` is only necessary because the
         // query is defined as taking a `ParamEnvAnd<Ty>`; it should
         // take a `ImpliedOutlivesBounds` instead
@@ -40,7 +40,7 @@ impl<'gcx: 'tcx, 'tcx> super::QueryTypeOp<'gcx, 'tcx> for ImpliedOutlivesBounds<
     }
 
     fn shrink_to_tcx_lifetime(
-        v: &'a CanonicalizedQueryResponse<'gcx, Self::QueryResponse>,
+        v: &'a CanonicalizedQueryResponse<'tcx, Self::QueryResponse>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, Self::QueryResponse>> {
         v
     }

src/librustc/traits/query/type_op/mod.rs

@@ -23,7 +23,7 @@ pub mod subtype;
 /// "Type ops" are used in NLL to perform some particular action and
 /// extract out the resulting region constraints (or an error if it
 /// cannot be completed).
-pub trait TypeOp<'gcx, 'tcx>: Sized + fmt::Debug {
+pub trait TypeOp<'tcx>: Sized + fmt::Debug {
     type Output;
 
     /// Processes the operation and all resulting obligations,
@@ -31,7 +31,7 @@ pub trait TypeOp<'gcx, 'tcx>: Sized + fmt::Debug {
     /// (they will be given over to the NLL region solver).
     fn fully_perform(
         self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
     ) -> Fallible<(Self::Output, Option<Rc<Vec<QueryRegionConstraint<'tcx>>>>)>;
 }
 
@@ -44,16 +44,16 @@ pub trait TypeOp<'gcx, 'tcx>: Sized + fmt::Debug {
 /// which produces the resulting query region constraints.
 ///
 /// [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
-pub trait QueryTypeOp<'gcx: 'tcx, 'tcx>:
-    fmt::Debug + Sized + TypeFoldable<'tcx> + Lift<'gcx>
+pub trait QueryTypeOp<'tcx>:
+    fmt::Debug + Sized + TypeFoldable<'tcx> + Lift<'tcx>
 {
-    type QueryResponse: TypeFoldable<'tcx> + Lift<'gcx>;
+    type QueryResponse: TypeFoldable<'tcx> + Lift<'tcx>;
 
     /// Give query the option for a simple fast path that never
     /// actually hits the tcx cache lookup etc. Return `Some(r)` with
     /// a final result or `None` to do the full path.
     fn try_fast_path(
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         key: &ParamEnvAnd<'tcx, Self>,
     ) -> Option<Self::QueryResponse>;
 
@@ -64,29 +64,29 @@ pub trait QueryTypeOp<'gcx: 'tcx, 'tcx>:
     /// bad, because it would create subregion relationships that are
     /// not captured in the return value.
     fn perform_query(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, Self::QueryResponse>>;
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Self>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self::QueryResponse>>;
 
     /// Casts a lifted query result (which is in the gcx lifetime)
     /// into the tcx lifetime. This is always just an identity cast,
     /// but the generic code doesn't realize it -- put another way, in
-    /// the generic code, we have a `Lifted<'gcx, Self::QueryResponse>`
+    /// the generic code, we have a `Lifted<'tcx, Self::QueryResponse>`
     /// and we want to convert that to a `Self::QueryResponse`. This is
     /// not a priori valid, so we can't do it -- but in practice, it
     /// is always a no-op (e.g., the lifted form of a type,
-    /// `Ty<'gcx>`, is a subtype of `Ty<'tcx>`). So we have to push
+    /// `Ty<'tcx>`, is a subtype of `Ty<'tcx>`). So we have to push
     /// the operation into the impls that know more specifically what
     /// `QueryResponse` is. This operation would (maybe) be nicer with
     /// something like HKTs or GATs, since then we could make
-    /// `QueryResponse` parametric and `'gcx` and `'tcx` etc.
+    /// `QueryResponse` parametric and `'tcx` and `'tcx` etc.
     fn shrink_to_tcx_lifetime(
-        lifted_query_result: &'a CanonicalizedQueryResponse<'gcx, Self::QueryResponse>,
+        lifted_query_result: &'a CanonicalizedQueryResponse<'tcx, Self::QueryResponse>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, Self::QueryResponse>>;
 
     fn fully_perform_into(
         query_key: ParamEnvAnd<'tcx, Self>,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
         output_query_region_constraints: &mut Vec<QueryRegionConstraint<'tcx>>,
     ) -> Fallible<Self::QueryResponse> {
         if let Some(result) = QueryTypeOp::try_fast_path(infcx.tcx, &query_key) {
@@ -133,15 +133,15 @@ pub trait QueryTypeOp<'gcx: 'tcx, 'tcx>:
     }
 }
 
-impl<'gcx: 'tcx, 'tcx, Q> TypeOp<'gcx, 'tcx> for ParamEnvAnd<'tcx, Q>
+impl<'tcx, Q> TypeOp<'tcx> for ParamEnvAnd<'tcx, Q>
 where
-    Q: QueryTypeOp<'gcx, 'tcx>,
+    Q: QueryTypeOp<'tcx>,
 {
     type Output = Q::QueryResponse;
 
     fn fully_perform(
         self,
-        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        infcx: &InferCtxt<'_, 'tcx>,
     ) -> Fallible<(Self::Output, Option<Rc<Vec<QueryRegionConstraint<'tcx>>>>)> {
         let mut qrc = vec![];
         let r = Q::fully_perform_into(self, infcx, &mut qrc)?;

src/librustc/traits/query/type_op/normalize.rs

@@ -18,13 +18,13 @@ where
     }
 }
 
-impl<'gcx: 'tcx, 'tcx, T> super::QueryTypeOp<'gcx, 'tcx> for Normalize<T>
+impl<'tcx, T> super::QueryTypeOp<'tcx> for Normalize<T>
 where
-    T: Normalizable<'gcx, 'tcx>,
+    T: Normalizable<'tcx>,
 {
     type QueryResponse = T;
 
-    fn try_fast_path(_tcx: TyCtxt<'gcx, 'tcx>, key: &ParamEnvAnd<'tcx, Self>) -> Option<T> {
+    fn try_fast_path(_tcx: TyCtxt<'tcx>, key: &ParamEnvAnd<'tcx, Self>) -> Option<T> {
         if !key.value.value.has_projections() {
             Some(key.value.value)
         } else {
@@ -33,99 +33,87 @@ where
     }
 
     fn perform_query(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, Self::QueryResponse>> {
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Self>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self::QueryResponse>> {
         T::type_op_method(tcx, canonicalized)
     }
 
     fn shrink_to_tcx_lifetime(
-        v: &'a CanonicalizedQueryResponse<'gcx, T>,
+        v: &'a CanonicalizedQueryResponse<'tcx, T>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, T>> {
         T::shrink_to_tcx_lifetime(v)
     }
 }
 
-pub trait Normalizable<'gcx, 'tcx>: fmt::Debug + TypeFoldable<'tcx> + Lift<'gcx> + Copy {
+pub trait Normalizable<'tcx>: fmt::Debug + TypeFoldable<'tcx> + Lift<'tcx> + Copy {
     fn type_op_method(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, Self>>;
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self>>;
 
-    /// Converts from the `'gcx` (lifted) form of `Self` into the `tcx`
+    /// Converts from the `'tcx` (lifted) form of `Self` into the `tcx`
     /// form of `Self`.
     fn shrink_to_tcx_lifetime(
-        v: &'a CanonicalizedQueryResponse<'gcx, Self>,
+        v: &'a CanonicalizedQueryResponse<'tcx, Self>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, Self>>;
 }
 
-impl Normalizable<'gcx, 'tcx> for Ty<'tcx>
-where
-    'gcx: 'tcx,
-{
+impl Normalizable<'tcx> for Ty<'tcx> {
     fn type_op_method(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, Self>> {
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self>> {
         tcx.type_op_normalize_ty(canonicalized)
     }
 
     fn shrink_to_tcx_lifetime(
-        v: &'a CanonicalizedQueryResponse<'gcx, Self>,
+        v: &'a CanonicalizedQueryResponse<'tcx, Self>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, Self>> {
         v
     }
 }
 
-impl Normalizable<'gcx, 'tcx> for ty::Predicate<'tcx>
-where
-    'gcx: 'tcx,
-{
+impl Normalizable<'tcx> for ty::Predicate<'tcx> {
     fn type_op_method(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, Self>> {
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self>> {
         tcx.type_op_normalize_predicate(canonicalized)
     }
 
     fn shrink_to_tcx_lifetime(
-        v: &'a CanonicalizedQueryResponse<'gcx, Self>,
+        v: &'a CanonicalizedQueryResponse<'tcx, Self>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, Self>> {
         v
     }
 }
 
-impl Normalizable<'gcx, 'tcx> for ty::PolyFnSig<'tcx>
-where
-    'gcx: 'tcx,
-{
+impl Normalizable<'tcx> for ty::PolyFnSig<'tcx> {
     fn type_op_method(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, Self>> {
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self>> {
         tcx.type_op_normalize_poly_fn_sig(canonicalized)
     }
 
     fn shrink_to_tcx_lifetime(
-        v: &'a CanonicalizedQueryResponse<'gcx, Self>,
+        v: &'a CanonicalizedQueryResponse<'tcx, Self>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, Self>> {
         v
     }
 }
 
-impl Normalizable<'gcx, 'tcx> for ty::FnSig<'tcx>
-where
-    'gcx: 'tcx,
-{
+impl Normalizable<'tcx> for ty::FnSig<'tcx> {
     fn type_op_method(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, Self>> {
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self>> {
         tcx.type_op_normalize_fn_sig(canonicalized)
     }
 
     fn shrink_to_tcx_lifetime(
-        v: &'a CanonicalizedQueryResponse<'gcx, Self>,
+        v: &'a CanonicalizedQueryResponse<'tcx, Self>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, Self>> {
         v
     }

src/librustc/traits/query/type_op/outlives.rs

@@ -15,14 +15,11 @@ impl<'tcx> DropckOutlives<'tcx> {
     }
 }
 
-impl super::QueryTypeOp<'gcx, 'tcx> for DropckOutlives<'tcx>
-where
-    'gcx: 'tcx,
-{
+impl super::QueryTypeOp<'tcx> for DropckOutlives<'tcx> {
     type QueryResponse = DropckOutlivesResult<'tcx>;
 
     fn try_fast_path(
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         key: &ParamEnvAnd<'tcx, Self>,
     ) -> Option<Self::QueryResponse> {
         if trivial_dropck_outlives(tcx, key.value.dropped_ty) {
@@ -33,9 +30,9 @@ where
     }
 
     fn perform_query(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, Self::QueryResponse>> {
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Self>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self::QueryResponse>> {
         // Subtle: note that we are not invoking
         // `infcx.at(...).dropck_outlives(...)` here, but rather the
         // underlying `dropck_outlives` query. This same underlying
@@ -58,7 +55,7 @@ where
     }
 
     fn shrink_to_tcx_lifetime(
-        lifted_query_result: &'a CanonicalizedQueryResponse<'gcx, Self::QueryResponse>,
+        lifted_query_result: &'a CanonicalizedQueryResponse<'tcx, Self::QueryResponse>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, Self::QueryResponse>> {
         lifted_query_result
     }

src/librustc/traits/query/type_op/prove_predicate.rs

@@ -13,11 +13,11 @@ impl<'tcx> ProvePredicate<'tcx> {
     }
 }
 
-impl<'gcx: 'tcx, 'tcx> super::QueryTypeOp<'gcx, 'tcx> for ProvePredicate<'tcx> {
+impl<'tcx> super::QueryTypeOp<'tcx> for ProvePredicate<'tcx> {
     type QueryResponse = ();
 
     fn try_fast_path(
-        tcx: TyCtxt<'gcx, 'tcx>,
+        tcx: TyCtxt<'tcx>,
         key: &ParamEnvAnd<'tcx, Self>,
     ) -> Option<Self::QueryResponse> {
         // Proving Sized, very often on "obviously sized" types like
@@ -38,14 +38,14 @@ impl<'gcx: 'tcx, 'tcx> super::QueryTypeOp<'gcx, 'tcx> for ProvePredicate<'tcx> {
     }
 
     fn perform_query(
-        tcx: TyCtxt<'gcx, 'tcx>,
-        canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Self>>,
-    ) -> Fallible<CanonicalizedQueryResponse<'gcx, ()>> {
+        tcx: TyCtxt<'tcx>,
+        canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Self>>,
+    ) -> Fallible<CanonicalizedQueryResponse<'tcx, ()>> {
         tcx.type_op_prove_predicate(canonicalized)
     }
 
     fn shrink_to_tcx_lifetime(
-        v: &'a CanonicalizedQueryResponse<'gcx, ()>,
+        v: &'a CanonicalizedQueryResponse<'tcx, ()>,
     ) -> &'a Canonical<'tcx, QueryResponse<'tcx, ()>> {
         v
     }