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Print closure signatures when reporting placeholder errors

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This commit is contained in:
Matthew Jasper 2021-02-09 23:00:33 +00:00
parent 94c11dfe78
commit 9337d4fde8
5 changed files with 38 additions and 12 deletions
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38
compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_error.rs
View file

@ -386,12 +386,38 @@ impl NiceRegionError<'me, 'tcx> {
let mut note = if same_self_type {
let mut self_ty = expected_trait_ref.map(|tr| tr.self_ty());
self_ty.highlight.maybe_highlighting_region(vid, actual_has_vid);
format!(
"{}`{}` must implement `{}`",
if leading_ellipsis { "..." } else { "" },
self_ty,
expected_trait_ref.map(|tr| tr.print_only_trait_path()),
)
if self_ty.value.is_closure()
&& self
.tcx()
.fn_trait_kind_from_lang_item(expected_trait_ref.value.def_id)
.is_some()
{
let closure_sig = self_ty.map(|closure| {
if let ty::Closure(_, substs) = closure.kind() {
self.tcx().signature_unclosure(
substs.as_closure().sig(),
rustc_hir::Unsafety::Normal,
)
} else {
bug!("type is not longer closure");
}
});
format!(
"{}closure with signature `{}` must implement `{}`",
if leading_ellipsis { "..." } else { "" },
closure_sig,
expected_trait_ref.map(|tr| tr.print_only_trait_path()),
)
} else {
format!(
"{}`{}` must implement `{}`",
if leading_ellipsis { "..." } else { "" },
self_ty,
expected_trait_ref.map(|tr| tr.print_only_trait_path()),
)
}
} else if passive_voice {
format!(
"{}`{}` would have to be implemented for the type `{}`",

2
src/test/ui/issues/issue-57843.stderr
View file

@ -4,7 +4,7 @@ error: implementation of `FnOnce` is not general enough
LL | Foo(Box::new(|_| ()));
| ^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
|
= note: `[closure@$DIR/issue-57843.rs:25:18: 25:24]` must implement `FnOnce<(&'1 bool,)>`, for any lifetime `'1`...
= note: closure with signature `fn(&'2 bool)` must implement `FnOnce<(&'1 bool,)>`, for any lifetime `'1`...
= note: ...but it actually implements `FnOnce<(&'2 bool,)>`, for some specific lifetime `'2`
error: aborting due to previous error

2
src/test/ui/lifetimes/issue-79187.stderr
View file

@ -4,7 +4,7 @@ error: implementation of `FnOnce` is not general enough
LL | thing(f);
| ^^^^^ implementation of `FnOnce` is not general enough
|
= note: `[closure@$DIR/issue-79187.rs:4:13: 4:19]` must implement `FnOnce<(&'1 u32,)>`, for any lifetime `'1`...
= note: closure with signature `fn(&'2 u32)` must implement `FnOnce<(&'1 u32,)>`, for any lifetime `'1`...
= note: ...but it actually implements `FnOnce<(&'2 u32,)>`, for some specific lifetime `'2`
error: aborting due to previous error

2
src/test/ui/type-alias-impl-trait/issue-57611-trait-alias.nll.stderr
View file

@ -30,7 +30,7 @@ error: implementation of `FnOnce` is not general enough
LL | type Bar = impl Baz<Self, Self>;
| ^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
|
= note: `[closure@$DIR/issue-57611-trait-alias.rs:25:9: 25:14]` must implement `FnOnce<(&'1 X,)>`, for any lifetime `'1`...
= note: closure with signature `fn(&'2 X) -> &'2 X` must implement `FnOnce<(&'1 X,)>`, for any lifetime `'1`...
= note: ...but it actually implements `FnOnce<(&'2 X,)>`, for some specific lifetime `'2`
error: aborting due to 4 previous errors

6
src/test/ui/type-alias-impl-trait/issue-57611-trait-alias.stderr
View file

@ -4,7 +4,7 @@ error: implementation of `FnOnce` is not general enough
LL | type Bar = impl Baz<Self, Self>;
| ^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
|
= note: `[closure@$DIR/issue-57611-trait-alias.rs:25:9: 25:14]` must implement `FnOnce<(&'1 X,)>`, for any lifetime `'1`...
= note: closure with signature `fn(&'2 X) -> &X` must implement `FnOnce<(&'1 X,)>`, for any lifetime `'1`...
= note: ...but it actually implements `FnOnce<(&'2 X,)>`, for some specific lifetime `'2`
error[E0308]: mismatched types
@ -27,7 +27,7 @@ error: implementation of `FnOnce` is not general enough
LL | type Bar = impl Baz<Self, Self>;
| ^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
|
= note: `[closure@$DIR/issue-57611-trait-alias.rs:25:9: 25:14]` must implement `FnOnce<(&'1 X,)>`, for any lifetime `'1`...
= note: closure with signature `fn(&'2 X) -> &'2 X` must implement `FnOnce<(&'1 X,)>`, for any lifetime `'1`...
= note: ...but it actually implements `FnOnce<(&'2 X,)>`, for some specific lifetime `'2`
error[E0308]: mismatched types
@ -50,7 +50,7 @@ error: implementation of `FnOnce` is not general enough
LL | type Bar = impl Baz<Self, Self>;
| ^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
|
= note: `[closure@$DIR/issue-57611-trait-alias.rs:25:9: 25:14]` must implement `FnOnce<(&'1 X,)>`, for any lifetime `'1`...
= note: closure with signature `fn(&'2 X) -> &'2 X` must implement `FnOnce<(&'1 X,)>`, for any lifetime `'1`...
= note: ...but it actually implements `FnOnce<(&'2 X,)>`, for some specific lifetime `'2`
error: aborting due to 5 previous errors