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Fallback to 'has type' error messages rather than 'lifetime appears in type'.

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This commit is contained in:
David Wood 2018-08-06 23:09:36 +02:00
parent 82b48277a2
commit 255ead5faa
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GPG key ID: 01760B4F9F53F154
2 changed files with 10 additions and 26 deletions
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34
src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs
View file

@ -242,17 +242,14 @@ impl<'tcx> RegionInferenceContext<'tcx> {
return Some(region_name);
}
let (_argument_name, argument_span) = self.get_argument_name_and_span_for_region(
mir, argument_index);
let region_name = self.synthesize_region_name(counter);
diag.span_label(
argument_span,
format!("lifetime `{}` appears in this argument", region_name,),
);
Some(region_name)
self.give_name_if_we_cannot_match_hir_ty(
infcx,
mir,
fr,
arg_ty,
counter,
diag,
)
}
fn give_name_if_we_can_match_hir_ty_from_argument(
@ -370,14 +367,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
search_stack.push((argument_ty, argument_hir_ty));
let mut closest_match: &hir::Ty = argument_hir_ty;
while let Some((ty, hir_ty)) = search_stack.pop() {
// While we search, also track the closet match.
if tcx.any_free_region_meets(&ty, |r| r.to_region_vid() == needle_fr) {
closest_match = hir_ty;
}
match (&ty.sty, &hir_ty.node) {
// Check if the `argument_ty` is `&'X ..` where `'X`
// is the region we are looking for -- if so, and we have a `&T`
@ -452,13 +442,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
}
}
let region_name = self.synthesize_region_name(counter);
diag.span_label(
closest_match.span,
format!("lifetime `{}` appears in this type", region_name),
);
return Some(region_name);
return None;
}
/// We've found an enum/struct/union type with the substitutions

2
src/test/ui/nll/issue-52742.stderr
View file

@ -4,7 +4,7 @@ error: unsatisfied lifetime constraints
LL | fn take_bar(&mut self, b: Bar<'_>) {
| --------- -- let's call this `'1`
| |
| lifetime `'2` appears in this type
| has type `&mut Foo<'_, '2>`
LL | self.y = b.z
| ^^^^^^^^^^^^ requires that `'1` must outlive `'2`