user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Verbose suggestion to make param const

Browse source 
```
error[E0747]: type provided when a constant was expected
  --> $DIR/invalid-const-arguments.rs:10:19
   |
LL | impl<N> Foo for B<N> {}
   |                   ^
   |
help: consider changing this type parameter to a const parameter
   |
LL - impl<N> Foo for B<N> {}
LL + impl<const N: u8> Foo for B<N> {}
   |
```
This commit is contained in:
Esteban Küber 2025-06-04 21:23:11 +00:00
parent df8102fe5f
commit 35cb28b7cf
3 changed files with 22 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

2
compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs
View file

@ -73,7 +73,7 @@ fn generic_arg_mismatch_err(
let param_name = tcx.hir_ty_param_name(param_local_id);
let param_type = tcx.type_of(param.def_id).instantiate_identity();
if param_type.is_suggestable(tcx, false) {
err.span_suggestion(
err.span_suggestion_verbose(
tcx.def_span(src_def_id),
"consider changing this type parameter to a const parameter",
format!("const {param_name}: {param_type}"),

10
tests/ui/const-generics/early/invalid-const-arguments.stderr
View file

@ -51,9 +51,13 @@ error[E0747]: type provided when a constant was expected
--> $DIR/invalid-const-arguments.rs:10:19
|
LL | impl<N> Foo for B<N> {}
| - ^
| |
| help: consider changing this type parameter to a const parameter: `const N: u8`
| ^
|
help: consider changing this type parameter to a const parameter
|
LL - impl<N> Foo for B<N> {}
LL + impl<const N: u8> Foo for B<N> {}
|
error[E0747]: unresolved item provided when a constant was expected
--> $DIR/invalid-const-arguments.rs:14:32

20
tests/ui/const-generics/kind_mismatch.stderr
View file

@ -2,17 +2,25 @@ error[E0747]: type provided when a constant was expected
--> $DIR/kind_mismatch.rs:11:38
|
LL | impl<K> ContainsKey<K> for KeyHolder<K> {}
| - ^
| |
| help: consider changing this type parameter to a const parameter: `const K: u8`
| ^
|
help: consider changing this type parameter to a const parameter
|
LL - impl<K> ContainsKey<K> for KeyHolder<K> {}
LL + impl<const K: u8> ContainsKey<K> for KeyHolder<K> {}
|
error[E0747]: type provided when a constant was expected
--> $DIR/kind_mismatch.rs:11:21
|
LL | impl<K> ContainsKey<K> for KeyHolder<K> {}
| - ^
| |
| help: consider changing this type parameter to a const parameter: `const K: u8`
| ^
|
help: consider changing this type parameter to a const parameter
|
LL - impl<K> ContainsKey<K> for KeyHolder<K> {}
LL + impl<const K: u8> ContainsKey<K> for KeyHolder<K> {}
|
error: aborting due to 2 previous errors