Rollup merge of rust-lang#123898 - fmease:gci-cmp-impl-item-lt-params, r=compiler-errors

Generic associated consts: Check regions earlier when comparing impl with trait item def

Fixes rust-lang#123836.

r? compiler-errors or compiler

Author: matthiaskrgr

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -1723,6 +1723,7 @@ pub(super) fn compare_impl_const_raw(
 
     compare_number_of_generics(tcx, impl_const_item, trait_const_item, false)?;
     compare_generic_param_kinds(tcx, impl_const_item, trait_const_item, false)?;
+    check_region_bounds_on_impl_item(tcx, impl_const_item, trait_const_item, false)?;
     compare_const_predicate_entailment(tcx, impl_const_item, trait_const_item, impl_trait_ref)
 }
 
@@ -1763,8 +1764,6 @@ fn compare_const_predicate_entailment<'tcx>(
     let impl_ct_predicates = tcx.predicates_of(impl_ct.def_id);
     let trait_ct_predicates = tcx.predicates_of(trait_ct.def_id);
 
-    check_region_bounds_on_impl_item(tcx, impl_ct, trait_ct, false)?;
-
     // The predicates declared by the impl definition, the trait and the
     // associated const in the trait are assumed.
     let impl_predicates = tcx.predicates_of(impl_ct_predicates.parent.unwrap());
@@ -1866,6 +1865,7 @@ pub(super) fn compare_impl_ty<'tcx>(
     let _: Result<(), ErrorGuaranteed> = try {
         compare_number_of_generics(tcx, impl_ty, trait_ty, false)?;
         compare_generic_param_kinds(tcx, impl_ty, trait_ty, false)?;
+        check_region_bounds_on_impl_item(tcx, impl_ty, trait_ty, false)?;
         compare_type_predicate_entailment(tcx, impl_ty, trait_ty, impl_trait_ref)?;
         check_type_bounds(tcx, trait_ty, impl_ty, impl_trait_ref)?;
     };
@@ -1886,8 +1886,6 @@ fn compare_type_predicate_entailment<'tcx>(
     let impl_ty_predicates = tcx.predicates_of(impl_ty.def_id);
     let trait_ty_predicates = tcx.predicates_of(trait_ty.def_id);
 
-    check_region_bounds_on_impl_item(tcx, impl_ty, trait_ty, false)?;
-
     let impl_ty_own_bounds = impl_ty_predicates.instantiate_own(tcx, impl_args);
     if impl_ty_own_bounds.len() == 0 {
         // Nothing to check.

tests/ui/generic-const-items/compare-impl-item.rs

@@ -6,9 +6,10 @@ trait Trait<P> {
     const B<const K: u64, const Q: u64>: u64;
     const C<T>: T;
     const D<const N: usize>: usize;
+    const E<'a>: &'a ();
 
-    const E: usize;
-    const F<T: PartialEq>: ();
+    const F: usize;
+    const G<T: PartialEq>: ();
 }
 
 impl<P> Trait<P> for () {
@@ -20,11 +21,13 @@ impl<P> Trait<P> for () {
     //~^ ERROR const `C` has 0 type parameters but its trait declaration has 1 type parameter
     const D<const N: u16>: u16 = N;
     //~^ ERROR const `D` has an incompatible generic parameter for trait `Trait`
+    const E: &'static () = &();
+    //~^ ERROR lifetime parameters or bounds on const `E` do not match the trait declaration
 
-    const E: usize = 1024
+    const F: usize = 1024
     where
         P: Copy; //~ ERROR impl has stricter requirements than trait
-    const F<T: Eq>: () = (); //~ ERROR impl has stricter requirements than trait
+    const G<T: Eq>: () = (); //~ ERROR impl has stricter requirements than trait
 }
 
 fn main() {}

tests/ui/generic-const-items/compare-impl-item.stderr

@@ -1,5 +1,5 @@
 error[E0049]: const `A` has 1 type parameter but its trait declaration has 0 type parameters
-  --> $DIR/compare-impl-item.rs:15:13
+  --> $DIR/compare-impl-item.rs:16:13
    |
 LL |     const A: ();
    |            - expected 0 type parameters
@@ -8,7 +8,7 @@ LL |     const A<T>: () = ();
    |             ^ found 1 type parameter
 
 error[E0049]: const `B` has 1 const parameter but its trait declaration has 2 const parameters
-  --> $DIR/compare-impl-item.rs:17:13
+  --> $DIR/compare-impl-item.rs:18:13
    |
 LL |     const B<const K: u64, const Q: u64>: u64;
    |             ------------  ------------
@@ -19,7 +19,7 @@ LL |     const B<const K: u64>: u64 = 0;
    |             ^^^^^^^^^^^^ found 1 const parameter
 
 error[E0049]: const `C` has 0 type parameters but its trait declaration has 1 type parameter
-  --> $DIR/compare-impl-item.rs:19:13
+  --> $DIR/compare-impl-item.rs:20:13
    |
 LL |     const C<T>: T;
    |             - expected 1 type parameter
@@ -28,7 +28,7 @@ LL |     const C<'a>: &'a str = "";
    |             ^^ found 0 type parameters
 
 error[E0053]: const `D` has an incompatible generic parameter for trait `Trait`
-  --> $DIR/compare-impl-item.rs:21:13
+  --> $DIR/compare-impl-item.rs:22:13
    |
 LL | trait Trait<P> {
    |       -----
@@ -42,25 +42,34 @@ LL | impl<P> Trait<P> for () {
 LL |     const D<const N: u16>: u16 = N;
    |             ^^^^^^^^^^^^ found const parameter of type `u16`
 
+error[E0195]: lifetime parameters or bounds on const `E` do not match the trait declaration
+  --> $DIR/compare-impl-item.rs:24:12
+   |
+LL |     const E<'a>: &'a ();
+   |            ---- lifetimes in impl do not match this const in trait
+...
+LL |     const E: &'static () = &();
+   |            ^ lifetimes do not match const in trait
+
 error[E0276]: impl has stricter requirements than trait
-  --> $DIR/compare-impl-item.rs:26:12
+  --> $DIR/compare-impl-item.rs:29:12
    |
-LL |     const E: usize;
-   |     -------------- definition of `E` from trait
+LL |     const F: usize;
+   |     -------------- definition of `F` from trait
 ...
 LL |         P: Copy;
    |            ^^^^ impl has extra requirement `P: Copy`
 
 error[E0276]: impl has stricter requirements than trait
-  --> $DIR/compare-impl-item.rs:27:16
+  --> $DIR/compare-impl-item.rs:30:16
    |
-LL |     const F<T: PartialEq>: ();
-   |     ------------------------- definition of `F` from trait
+LL |     const G<T: PartialEq>: ();
+   |     ------------------------- definition of `G` from trait
 ...
-LL |     const F<T: Eq>: () = ();
+LL |     const G<T: Eq>: () = ();
    |                ^^ impl has extra requirement `T: Eq`
 
-error: aborting due to 6 previous errors
+error: aborting due to 7 previous errors
 
-Some errors have detailed explanations: E0049, E0053, E0276.
+Some errors have detailed explanations: E0049, E0053, E0195, E0276.
 For more information about an error, try `rustc --explain E0049`.