Rollup merge of #99911 - cjgillot:no-guess, r=davidtwco

Remove some uses of `guess_head_span`

That function cuts a span at the first occurrence of `{`.  Using `def_span` is almost always more precise.

compiler/rustc_lint/src/builtin.rs

@@ -1364,7 +1364,6 @@ impl UnreachablePub {
         cx: &LateContext<'_>,
         what: &str,
         def_id: LocalDefId,
-        span: Span,
         vis_span: Span,
         exportable: bool,
     ) {
@@ -1373,7 +1372,7 @@ impl UnreachablePub {
             if vis_span.from_expansion() {
                 applicability = Applicability::MaybeIncorrect;
             }
-            let def_span = cx.tcx.sess.source_map().guess_head_span(span);
+            let def_span = cx.tcx.def_span(def_id);
             cx.struct_span_lint(UNREACHABLE_PUB, def_span, |lint| {
                 let mut err = lint.build(fluent::lint::builtin_unreachable_pub);
                 err.set_arg("what", what);
@@ -1399,36 +1398,22 @@ impl<'tcx> LateLintPass<'tcx> for UnreachablePub {
         if let hir::ItemKind::Use(_, hir::UseKind::ListStem) = &item.kind {
             return;
         }
-        self.perform_lint(cx, "item", item.def_id, item.span, item.vis_span, true);
+        self.perform_lint(cx, "item", item.def_id, item.vis_span, true);
     }
 
     fn check_foreign_item(&mut self, cx: &LateContext<'_>, foreign_item: &hir::ForeignItem<'tcx>) {
-        self.perform_lint(
-            cx,
-            "item",
-            foreign_item.def_id,
-            foreign_item.span,
-            foreign_item.vis_span,
-            true,
-        );
+        self.perform_lint(cx, "item", foreign_item.def_id, foreign_item.vis_span, true);
     }
 
     fn check_field_def(&mut self, cx: &LateContext<'_>, field: &hir::FieldDef<'_>) {
         let def_id = cx.tcx.hir().local_def_id(field.hir_id);
-        self.perform_lint(cx, "field", def_id, field.span, field.vis_span, false);
+        self.perform_lint(cx, "field", def_id, field.vis_span, false);
     }
 
     fn check_impl_item(&mut self, cx: &LateContext<'_>, impl_item: &hir::ImplItem<'_>) {
         // Only lint inherent impl items.
         if cx.tcx.associated_item(impl_item.def_id).trait_item_def_id.is_none() {
-            self.perform_lint(
-                cx,
-                "item",
-                impl_item.def_id,
-                impl_item.span,
-                impl_item.vis_span,
-                false,
-            );
+            self.perform_lint(cx, "item", impl_item.def_id, impl_item.vis_span, false);
         }
     }
 }

compiler/rustc_mir_build/src/lints.rs

@@ -1,7 +1,7 @@
 use rustc_data_structures::graph::iterate::{
     NodeStatus, TriColorDepthFirstSearch, TriColorVisitor,
 };
-use rustc_hir::intravisit::FnKind;
+use rustc_hir::def::DefKind;
 use rustc_middle::mir::{BasicBlock, BasicBlocks, Body, Operand, TerminatorKind};
 use rustc_middle::ty::subst::{GenericArg, InternalSubsts};
 use rustc_middle::ty::{self, AssocItem, AssocItemContainer, Instance, TyCtxt};
@@ -12,12 +12,7 @@ use std::ops::ControlFlow;
 pub(crate) fn check<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
     let def_id = body.source.def_id().expect_local();
 
-    if let Some(fn_kind) = tcx.hir().get_by_def_id(def_id).fn_kind() {
-        if let FnKind::Closure = fn_kind {
-            // closures can't recur, so they don't matter.
-            return;
-        }
-
+    if let DefKind::Fn | DefKind::AssocFn = tcx.def_kind(def_id) {
         // If this is trait/impl method, extract the trait's substs.
         let trait_substs = match tcx.opt_associated_item(def_id.to_def_id()) {
             Some(AssocItem {
@@ -41,8 +36,8 @@ pub(crate) fn check<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
 
         vis.reachable_recursive_calls.sort();
 
+        let sp = tcx.def_span(def_id);
         let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
-        let sp = tcx.sess.source_map().guess_head_span(tcx.hir().span_with_body(hir_id));
         tcx.struct_span_lint_hir(UNCONDITIONAL_RECURSION, hir_id, sp, |lint| {
             let mut db = lint.build("function cannot return without recursing");
             db.span_label(sp, "cannot return without recursing");

compiler/rustc_privacy/src/lib.rs

@@ -1754,8 +1754,7 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
                 || self.in_assoc_ty
                 || self.tcx.resolutions(()).has_pub_restricted
             {
-                let vis_span =
-                    self.tcx.sess.source_map().guess_head_span(self.tcx.def_span(def_id));
+                let vis_span = self.tcx.def_span(def_id);
                 if kind == "trait" {
                     self.tcx.sess.emit_err(InPublicInterfaceTraits {
                         span,

compiler/rustc_query_system/src/query/job.rs

@@ -1,4 +1,3 @@
-use crate::dep_graph::DepContext;
 use crate::query::plumbing::CycleError;
 use crate::query::{QueryContext, QueryStackFrame};
 use rustc_hir::def::DefKind;
@@ -536,17 +535,13 @@ pub(crate) fn report_cycle<'a>(
 ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
     assert!(!stack.is_empty());
 
-    let fix_span = |span: Span, query: &QueryStackFrame| {
-        sess.source_map().guess_head_span(query.default_span(span))
-    };
-
-    let span = fix_span(stack[1 % stack.len()].span, &stack[0].query);
+    let span = stack[0].query.default_span(stack[1 % stack.len()].span);
     let mut err =
         struct_span_err!(sess, span, E0391, "cycle detected when {}", stack[0].query.description);
 
     for i in 1..stack.len() {
         let query = &stack[i].query;
-        let span = fix_span(stack[(i + 1) % stack.len()].span, query);
+        let span = query.default_span(stack[(i + 1) % stack.len()].span);
         err.span_note(span, &format!("...which requires {}...", query.description));
     }
 
@@ -577,7 +572,7 @@ pub(crate) fn report_cycle<'a>(
     }
 
     if let Some((span, query)) = usage {
-        err.span_note(fix_span(span, &query), &format!("cycle used when {}", query.description));
+        err.span_note(query.default_span(span), &format!("cycle used when {}", query.description));
     }
 
     err
@@ -606,8 +601,7 @@ pub fn print_query_stack<CTX: QueryContext>(
             Level::FailureNote,
             &format!("#{} [{}] {}", i, query_info.query.name, query_info.query.description),
         );
-        diag.span =
-            tcx.dep_context().sess().source_map().guess_head_span(query_info.job.span).into();
+        diag.span = query_info.job.span.into();
         handler.force_print_diagnostic(diag);
 
         current_query = query_info.job.parent;

compiler/rustc_resolve/src/diagnostics.rs

@@ -1587,11 +1587,7 @@ impl<'a> Resolver<'a> {
         };
         let def_span = suggestion.res.opt_def_id().and_then(|def_id| match def_id.krate {
             LOCAL_CRATE => self.opt_span(def_id),
-            _ => Some(
-                self.session
-                    .source_map()
-                    .guess_head_span(self.cstore().get_span_untracked(def_id, self.session)),
-            ),
+            _ => Some(self.cstore().get_span_untracked(def_id, self.session)),
         });
         if let Some(def_span) = def_span {
             if span.overlaps(def_span) {

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -136,12 +136,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
     fn def_span(&self, def_id: DefId) -> Option<Span> {
         match def_id.krate {
             LOCAL_CRATE => self.r.opt_span(def_id),
-            _ => Some(
-                self.r
-                    .session
-                    .source_map()
-                    .guess_head_span(self.r.cstore().get_span_untracked(def_id, self.r.session)),
-            ),
+            _ => Some(self.r.cstore().get_span_untracked(def_id, self.r.session)),
         }
     }
 

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1946,7 +1946,6 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
             ));
 
             let original_span = err.span.primary_span().unwrap();
-            let original_span = self.tcx.sess.source_map().guess_head_span(original_span);
             let mut span = MultiSpan::from_span(original_span);
 
             let message = outer_generator

compiler/rustc_typeck/src/check/_match.rs

@@ -293,6 +293,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub(crate) fn if_cause(
         &self,
         span: Span,
+        cond_span: Span,
         then_expr: &'tcx hir::Expr<'tcx>,
         else_expr: &'tcx hir::Expr<'tcx>,
         then_ty: Ty<'tcx>,
@@ -355,10 +356,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // 6 | |     };
             //   | |_____^ expected integer, found `()`
             // ```
-            if block.expr.is_none() && block.stmts.is_empty()
-                && let Some(outer_span) = &mut outer_span
-            {
-                *outer_span = self.tcx.sess.source_map().guess_head_span(*outer_span);
+            if block.expr.is_none() && block.stmts.is_empty() && outer_span.is_some() {
+                let sp = if let Some(cs) = cond_span.find_ancestor_inside(span) {
+                    span.with_hi(cs.hi())
+                } else {
+                    span
+                };
+                outer_span = Some(sp);
             }
 
             (self.find_block_span(block), block.hir_id)

compiler/rustc_typeck/src/check/expr.rs

@@ -1003,8 +1003,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let else_diverges = self.diverges.get();
 
             let opt_suggest_box_span = self.opt_suggest_box_span(else_ty, orig_expected);
-            let if_cause =
-                self.if_cause(sp, then_expr, else_expr, then_ty, else_ty, opt_suggest_box_span);
+            let if_cause = self.if_cause(
+                sp,
+                cond_expr.span,
+                then_expr,
+                else_expr,
+                then_ty,
+                else_ty,
+                opt_suggest_box_span,
+            );
 
             coerce.coerce(self, &if_cause, else_expr, else_ty);
 

src/test/ui/async-await/no-const-async.stderr

@@ -35,7 +35,7 @@ note: cycle used when checking item types in top-level module
   --> $DIR/no-const-async.rs:4:1
    |
 LL | pub const async fn x() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

src/test/ui/consts/issue-44415.stderr

@@ -2,18 +2,18 @@ error[E0391]: cycle detected when evaluating type-level constant
   --> $DIR/issue-44415.rs:6:17
    |
 LL |     bytes: [u8; unsafe { intrinsics::size_of::<Foo>() }],
-   |                 ^^^^^^
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: ...which requires const-evaluating + checking `Foo::bytes::{constant#0}`...
   --> $DIR/issue-44415.rs:6:17
    |
 LL |     bytes: [u8; unsafe { intrinsics::size_of::<Foo>() }],
-   |                 ^^^^^^
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires const-evaluating + checking `Foo::bytes::{constant#0}`...
   --> $DIR/issue-44415.rs:6:17
    |
 LL |     bytes: [u8; unsafe { intrinsics::size_of::<Foo>() }],
-   |                 ^^^^^^
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: ...which requires computing layout of `Foo`...
    = note: ...which requires computing layout of `[u8; _]`...
    = note: ...which requires normalizing `[u8; _]`...

src/test/ui/cycle-trait/cycle-trait-default-type-trait.stderr

@@ -8,8 +8,13 @@ LL | trait Foo<X = Box<dyn Foo>> {
 note: cycle used when collecting item types in top-level module
   --> $DIR/cycle-trait-default-type-trait.rs:4:1
    |
-LL | trait Foo<X = Box<dyn Foo>> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | / trait Foo<X = Box<dyn Foo>> {
+LL | |
+LL | |
+LL | | }
+LL | |
+LL | | fn main() { }
+   | |_____________^
 
 error[E0391]: cycle detected when computing type of `Foo::X`
   --> $DIR/cycle-trait-default-type-trait.rs:4:23
@@ -21,8 +26,13 @@ LL | trait Foo<X = Box<dyn Foo>> {
 note: cycle used when collecting item types in top-level module
   --> $DIR/cycle-trait-default-type-trait.rs:4:1
    |
-LL | trait Foo<X = Box<dyn Foo>> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | / trait Foo<X = Box<dyn Foo>> {
+LL | |
+LL | |
+LL | | }
+LL | |
+LL | | fn main() { }
+   | |_____________^
 
 error: aborting due to 2 previous errors
 

src/test/ui/cycle-trait/cycle-trait-supertrait-direct.stderr

@@ -13,8 +13,10 @@ LL | trait Chromosome: Chromosome {
 note: cycle used when collecting item types in top-level module
   --> $DIR/cycle-trait-supertrait-direct.rs:3:1
    |
-LL | trait Chromosome: Chromosome {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | / trait Chromosome: Chromosome {
+LL | |
+LL | | }
+   | |_^
 
 error: aborting due to previous error
 

src/test/ui/hrtb/hrtb-perfect-forwarding.stderr

@@ -4,12 +4,10 @@ warning: function cannot return without recursing
 LL | / fn no_hrtb<'b, T>(mut t: T)
 LL | | where
 LL | |     T: Bar<&'b isize>,
-LL | | {
-...  |
-LL | |     no_hrtb(&mut t);
-   | |     --------------- recursive call site
-LL | | }
-   | |_^ cannot return without recursing
+   | |______________________^ cannot return without recursing
+...
+LL |       no_hrtb(&mut t);
+   |       --------------- recursive call site
    |
    = note: `#[warn(unconditional_recursion)]` on by default
    = help: a `loop` may express intention better if this is on purpose
@@ -20,12 +18,10 @@ warning: function cannot return without recursing
 LL | / fn bar_hrtb<T>(mut t: T)
 LL | | where
 LL | |     T: for<'b> Bar<&'b isize>,
-LL | | {
-...  |
-LL | |     bar_hrtb(&mut t);
-   | |     ---------------- recursive call site
-LL | | }
-   | |_^ cannot return without recursing
+   | |______________________________^ cannot return without recursing
+...
+LL |       bar_hrtb(&mut t);
+   |       ---------------- recursive call site
    |
    = help: a `loop` may express intention better if this is on purpose
 
@@ -35,14 +31,10 @@ warning: function cannot return without recursing
 LL | / fn foo_hrtb_bar_not<'b, T>(mut t: T)
 LL | | where
 LL | |     T: for<'a> Foo<&'a isize> + Bar<&'b isize>,
-LL | | {
-...  |
-LL | |     foo_hrtb_bar_not(&mut t);
-   | |     ------------------------ recursive call site
-LL | |
-LL | |
-LL | | }
-   | |_^ cannot return without recursing
+   | |_______________________________________________^ cannot return without recursing
+...
+LL |       foo_hrtb_bar_not(&mut t);
+   |       ------------------------ recursive call site
    |
    = help: a `loop` may express intention better if this is on purpose
 
@@ -70,12 +62,10 @@ warning: function cannot return without recursing
 LL | / fn foo_hrtb_bar_hrtb<T>(mut t: T)
 LL | | where
 LL | |     T: for<'a> Foo<&'a isize> + for<'b> Bar<&'b isize>,
-LL | | {
-LL | |     // OK -- now we have `T : for<'b> Bar<&'b isize>`.
-LL | |     foo_hrtb_bar_hrtb(&mut t);
-   | |     ------------------------- recursive call site
-LL | | }
-   | |_^ cannot return without recursing
+   | |_______________________________________________________^ cannot return without recursing
+...
+LL |       foo_hrtb_bar_hrtb(&mut t);
+   |       ------------------------- recursive call site
    |
    = help: a `loop` may express intention better if this is on purpose
 

src/test/ui/issues/issue-12511.stderr

@@ -23,8 +23,10 @@ LL | trait T2 : T1 {
 note: cycle used when collecting item types in top-level module
   --> $DIR/issue-12511.rs:1:1
    |
-LL | trait T1 : T2 {
-   | ^^^^^^^^^^^^^
+LL | / trait T1 : T2 {
+LL | |
+LL | | }
+   | |_^
 
 error: aborting due to previous error
 

src/test/ui/lint/unreachable_pub.stderr

@@ -1,8 +1,8 @@
 warning: unreachable `pub` item
-  --> $DIR/unreachable_pub.rs:8:5
+  --> $DIR/unreachable_pub.rs:8:13
    |
 LL |     pub use std::fmt;
-   |     ---^^^^^^^^^^^^^^
+   |     ---     ^^^^^^^^
    |     |
    |     help: consider restricting its visibility: `pub(crate)`
    |
@@ -93,7 +93,7 @@ warning: unreachable `pub` item
   --> $DIR/unreachable_pub.rs:33:5
    |
 LL |     pub const CARBON: usize = 1;
-   |     ---^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---^^^^^^^^^^^^^^^^^^^^
    |     |
    |     help: consider restricting its visibility: `pub(crate)`
    |
@@ -103,7 +103,7 @@ warning: unreachable `pub` item
   --> $DIR/unreachable_pub.rs:34:5
    |
 LL |     pub static NITROGEN: usize = 2;
-   |     ---^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---^^^^^^^^^^^^^^^^^^^^^^^
    |     |
    |     help: consider restricting its visibility: `pub(crate)`
    |
@@ -113,7 +113,7 @@ warning: unreachable `pub` item
   --> $DIR/unreachable_pub.rs:35:5
    |
 LL |     pub type Oxygen = bool;
-   |     ---^^^^^^^^^^^^^^^^^^^^
+   |     ---^^^^^^^^^^^^
    |     |
    |     help: consider restricting its visibility: `pub(crate)`
    |
@@ -123,7 +123,7 @@ warning: unreachable `pub` item
   --> $DIR/unreachable_pub.rs:38:47
    |
 LL |         ($visibility: vis, $name: ident) => { $visibility struct $name {} }
-   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 ...
 LL |     define_empty_struct_with_visibility!(pub, Fluorine);
    |     ---------------------------------------------------
@@ -138,7 +138,7 @@ warning: unreachable `pub` item
   --> $DIR/unreachable_pub.rs:44:9
    |
 LL |         pub fn catalyze() -> bool;
-   |         ---^^^^^^^^^^^^^^^^^^^^^^^
+   |         ---^^^^^^^^^^^^^^^^^^^^^^
    |         |
    |         help: consider restricting its visibility: `pub(crate)`
    |

src/test/ui/resolve/issue-23305.stderr

@@ -8,8 +8,14 @@ LL | impl dyn ToNbt<Self> {}
 note: cycle used when collecting item types in top-level module
   --> $DIR/issue-23305.rs:1:1
    |
-LL | pub trait ToNbt<T> {
-   | ^^^^^^^^^^^^^^^^^^
+LL | / pub trait ToNbt<T> {
+LL | |     fn new(val: T) -> Self;
+LL | | }
+LL | |
+...  |
+LL | |
+LL | | fn main() {}
+   | |____________^
 
 error: aborting due to previous error
 

src/test/ui/traits/issue-91949-hangs-on-recursion.stderr

@@ -4,11 +4,10 @@ warning: function cannot return without recursing
 LL | / fn recurse<T>(elements: T) -> Vec<char>
 LL | | where
 LL | |     T: Iterator<Item = ()>,
-LL | | {
-LL | |     recurse(IteratorOfWrapped(elements).map(|t| t.0))
-   | |     ------------------------------------------------- recursive call site
-LL | | }
-   | |_^ cannot return without recursing
+   | |___________________________^ cannot return without recursing
+LL |   {
+LL |       recurse(IteratorOfWrapped(elements).map(|t| t.0))
+   |       ------------------------------------------------- recursive call site
    |
    = note: `#[warn(unconditional_recursion)]` on by default
    = help: a `loop` may express intention better if this is on purpose

src/test/ui/traits/trait-upcasting/cyclic-trait-resolution.stderr

@@ -14,7 +14,7 @@ note: cycle used when collecting item types in top-level module
   --> $DIR/cyclic-trait-resolution.rs:1:1
    |
 LL | trait A: B + A {}
-   | ^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 

src/test/ui/type-alias-enum-variants/self-in-enum-definition.stderr

@@ -2,18 +2,18 @@ error[E0391]: cycle detected when simplifying constant for the type system `Alph
   --> $DIR/self-in-enum-definition.rs:5:10
    |
 LL |     V3 = Self::V1 {} as u8 + 2,
-   |          ^^^^^^^^
+   |          ^^^^^^^^^^^^^^^^^^^^^
    |
 note: ...which requires simplifying constant for the type system `Alpha::V3::{constant#0}`...
   --> $DIR/self-in-enum-definition.rs:5:10
    |
 LL |     V3 = Self::V1 {} as u8 + 2,
-   |          ^^^^^^^^
+   |          ^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires const-evaluating + checking `Alpha::V3::{constant#0}`...
   --> $DIR/self-in-enum-definition.rs:5:10
    |
 LL |     V3 = Self::V1 {} as u8 + 2,
-   |          ^^^^^^^^
+   |          ^^^^^^^^^^^^^^^^^^^^^
    = note: ...which requires computing layout of `Alpha`...
    = note: ...which again requires simplifying constant for the type system `Alpha::V3::{constant#0}`, completing the cycle
 note: cycle used when collecting item types in top-level module