diff --git a/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs b/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs
index 0df5a57bc2c..4823472cf96 100644
--- a/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs
+++ b/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs
@@ -144,6 +144,7 @@ impl<'tcx> InherentCollect<'tcx> {
let id = id.owner_id.def_id;
let item_span = self.tcx.def_span(id);
let self_ty = self.tcx.type_of(id).instantiate_identity();
+ let self_ty = peel_off_weak_aliases(self.tcx, self_ty);
match *self_ty.kind() {
ty::Adt(def, _) => self.check_def_id(id, self_ty, def.did()),
ty::Foreign(did) => self.check_def_id(id, self_ty, did),
@@ -166,7 +167,7 @@ impl<'tcx> InherentCollect<'tcx> {
| ty::Never
| ty::FnPtr(_)
| ty::Tuple(..) => self.check_primitive_impl(id, self_ty),
- ty::Alias(..) | ty::Param(_) => {
+ ty::Alias(ty::Projection | ty::Inherent | ty::Opaque, _) | ty::Param(_) => {
Err(self.tcx.dcx().emit_err(errors::InherentNominal { span: item_span }))
}
ty::FnDef(..)
@@ -174,6 +175,7 @@ impl<'tcx> InherentCollect<'tcx> {
| ty::CoroutineClosure(..)
| ty::Coroutine(..)
| ty::CoroutineWitness(..)
+ | ty::Alias(ty::Weak, _)
| ty::Bound(..)
| ty::Placeholder(_)
| ty::Infer(_) => {
@@ -184,3 +186,30 @@ impl<'tcx> InherentCollect<'tcx> {
}
}
}
+
+/// Peel off all weak alias types in this type until there are none left.
+///
+///
+///
+/// This assumes that `ty` gets normalized later and that any overflows occurring
+/// during said normalization get reported.
+///
+///
+fn peel_off_weak_aliases<'tcx>(tcx: TyCtxt<'tcx>, mut ty: Ty<'tcx>) -> Ty<'tcx> {
+ let ty::Alias(ty::Weak, _) = ty.kind() else { return ty };
+
+ let limit = tcx.recursion_limit();
+ let mut depth = 0;
+
+ while let ty::Alias(ty::Weak, alias) = ty.kind() {
+ if !limit.value_within_limit(depth) {
+ let guar = tcx.dcx().delayed_bug("overflow expanding weak alias type");
+ return Ty::new_error(tcx, guar);
+ }
+
+ ty = tcx.type_of(alias.def_id).instantiate(tcx, alias.args);
+ depth += 1;
+ }
+
+ ty
+}
diff --git a/tests/ui/lazy-type-alias/inherent-impls-conflicting.rs b/tests/ui/lazy-type-alias/inherent-impls-conflicting.rs
new file mode 100644
index 00000000000..2adb04839ae
--- /dev/null
+++ b/tests/ui/lazy-type-alias/inherent-impls-conflicting.rs
@@ -0,0 +1,10 @@
+#![feature(lazy_type_alias)]
+#![allow(incomplete_features)]
+
+type Alias = Local;
+struct Local;
+
+impl Alias { fn method() {} } //~ ERROR duplicate definitions with name `method`
+impl Local { fn method() {} }
+
+fn main() {}
diff --git a/tests/ui/lazy-type-alias/inherent-impls-conflicting.stderr b/tests/ui/lazy-type-alias/inherent-impls-conflicting.stderr
new file mode 100644
index 00000000000..3f8dcef857f
--- /dev/null
+++ b/tests/ui/lazy-type-alias/inherent-impls-conflicting.stderr
@@ -0,0 +1,11 @@
+error[E0592]: duplicate definitions with name `method`
+ --> $DIR/inherent-impls-conflicting.rs:7:14
+ |
+LL | impl Alias { fn method() {} }
+ | ^^^^^^^^^^^ duplicate definitions for `method`
+LL | impl Local { fn method() {} }
+ | ----------- other definition for `method`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0592`.
diff --git a/tests/ui/lazy-type-alias/inherent-impls-not-nominal.rs b/tests/ui/lazy-type-alias/inherent-impls-not-nominal.rs
new file mode 100644
index 00000000000..0ec23bb7fb7
--- /dev/null
+++ b/tests/ui/lazy-type-alias/inherent-impls-not-nominal.rs
@@ -0,0 +1,12 @@
+#![feature(lazy_type_alias)]
+#![allow(incomplete_features)]
+
+type Alias = <() as Trait>::Out;
+
+trait Trait { type Out; }
+impl Trait for () { type Out = Local; }
+struct Local;
+
+impl Alias {} //~ ERROR no nominal type found for inherent implementation
+
+fn main() {}
diff --git a/tests/ui/lazy-type-alias/inherent-impls-not-nominal.stderr b/tests/ui/lazy-type-alias/inherent-impls-not-nominal.stderr
new file mode 100644
index 00000000000..2936e70f5b4
--- /dev/null
+++ b/tests/ui/lazy-type-alias/inherent-impls-not-nominal.stderr
@@ -0,0 +1,11 @@
+error[E0118]: no nominal type found for inherent implementation
+ --> $DIR/inherent-impls-not-nominal.rs:10:1
+ |
+LL | impl Alias {}
+ | ^^^^^^^^^^ impl requires a nominal type
+ |
+ = note: either implement a trait on it or create a newtype to wrap it instead
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0118`.
diff --git a/tests/ui/lazy-type-alias/inherent-impls-overflow.classic.stderr b/tests/ui/lazy-type-alias/inherent-impls-overflow.classic.stderr
new file mode 100644
index 00000000000..1cace470627
--- /dev/null
+++ b/tests/ui/lazy-type-alias/inherent-impls-overflow.classic.stderr
@@ -0,0 +1,43 @@
+error[E0275]: overflow evaluating the requirement `Loop`
+ --> $DIR/inherent-impls-overflow.rs:7:13
+ |
+LL | type Loop = Loop;
+ | ^^^^
+ |
+ = note: in case this is a recursive type alias, consider using a struct, enum, or union instead
+
+error[E0275]: overflow evaluating the requirement `Loop`
+ --> $DIR/inherent-impls-overflow.rs:9:1
+ |
+LL | impl Loop {}
+ | ^^^^^^^^^^^^
+ |
+ = note: in case this is a recursive type alias, consider using a struct, enum, or union instead
+
+error[E0275]: overflow evaluating the requirement `Poly0<((((((...,),),),),),)>`
+ --> $DIR/inherent-impls-overflow.rs:11:17
+ |
+LL | type Poly0 = Poly1<(T,)>;
+ | ^^^^^^^^^^^
+ |
+ = note: in case this is a recursive type alias, consider using a struct, enum, or union instead
+
+error[E0275]: overflow evaluating the requirement `Poly1<((((((...,),),),),),)>`
+ --> $DIR/inherent-impls-overflow.rs:14:17
+ |
+LL | type Poly1 = Poly0<(T,)>;
+ | ^^^^^^^^^^^
+ |
+ = note: in case this is a recursive type alias, consider using a struct, enum, or union instead
+
+error[E0275]: overflow evaluating the requirement `Poly1<((((((...,),),),),),)>`
+ --> $DIR/inherent-impls-overflow.rs:18:1
+ |
+LL | impl Poly0<()> {}
+ | ^^^^^^^^^^^^^^^^^
+ |
+ = note: in case this is a recursive type alias, consider using a struct, enum, or union instead
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0275`.
diff --git a/tests/ui/lazy-type-alias/inherent-impls-overflow.next.stderr b/tests/ui/lazy-type-alias/inherent-impls-overflow.next.stderr
new file mode 100644
index 00000000000..1a6259b5cf9
--- /dev/null
+++ b/tests/ui/lazy-type-alias/inherent-impls-overflow.next.stderr
@@ -0,0 +1,38 @@
+error[E0275]: overflow evaluating the requirement `Loop == _`
+ --> $DIR/inherent-impls-overflow.rs:9:6
+ |
+LL | impl Loop {}
+ | ^^^^
+ |
+ = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`inherent_impls_overflow`)
+
+error[E0392]: type parameter `T` is never used
+ --> $DIR/inherent-impls-overflow.rs:11:12
+ |
+LL | type Poly0 = Poly1<(T,)>;
+ | ^ unused type parameter
+ |
+ = help: consider removing `T` or referring to it in the body of the type alias
+ = help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead
+
+error[E0392]: type parameter `T` is never used
+ --> $DIR/inherent-impls-overflow.rs:14:12
+ |
+LL | type Poly1 = Poly0<(T,)>;
+ | ^ unused type parameter
+ |
+ = help: consider removing `T` or referring to it in the body of the type alias
+ = help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead
+
+error[E0275]: overflow evaluating the requirement `Poly0<()> == _`
+ --> $DIR/inherent-impls-overflow.rs:18:6
+ |
+LL | impl Poly0<()> {}
+ | ^^^^^^^^^
+ |
+ = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`inherent_impls_overflow`)
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0275, E0392.
+For more information about an error, try `rustc --explain E0275`.
diff --git a/tests/ui/lazy-type-alias/inherent-impls-overflow.rs b/tests/ui/lazy-type-alias/inherent-impls-overflow.rs
new file mode 100644
index 00000000000..b260dedeb07
--- /dev/null
+++ b/tests/ui/lazy-type-alias/inherent-impls-overflow.rs
@@ -0,0 +1,20 @@
+//@ revisions: classic next
+//@[next] compile-flags: -Znext-solver
+
+#![feature(lazy_type_alias)]
+#![allow(incomplete_features)]
+
+type Loop = Loop; //[classic]~ ERROR overflow evaluating the requirement
+
+impl Loop {} //~ ERROR overflow evaluating the requirement
+
+type Poly0 = Poly1<(T,)>;
+//[classic]~^ ERROR overflow evaluating the requirement
+//[next]~^^ ERROR type parameter `T` is never used
+type Poly1 = Poly0<(T,)>;
+//[classic]~^ ERROR overflow evaluating the requirement
+//[next]~^^ ERROR type parameter `T` is never used
+
+impl Poly0<()> {} //~ ERROR overflow evaluating the requirement
+
+fn main() {}
diff --git a/tests/ui/lazy-type-alias/inherent-impls.rs b/tests/ui/lazy-type-alias/inherent-impls.rs
new file mode 100644
index 00000000000..835b70bf67a
--- /dev/null
+++ b/tests/ui/lazy-type-alias/inherent-impls.rs
@@ -0,0 +1,18 @@
+//@ check-pass
+
+#![feature(lazy_type_alias)]
+#![allow(incomplete_features)]
+
+type Alias = Local;
+struct Local;
+
+impl Alias {
+ fn method(self) {}
+}
+
+fn main() {
+ let _ = Local.method();
+ let _ = Local::method;
+ let _ = Alias {}.method();
+ let _ = Alias::method;
+}