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Fix lifetime generics in <T<..> as Trait>::try_from suggestion.

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This commit is contained in:
Mara Bos 2021-08-30 19:01:34 +02:00
parent a4f6d3e5c2
commit e2abf06890
1 changed files with 21 additions and 17 deletions
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38
compiler/rustc_typeck/src/check/method/prelude2021.rs
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@ -262,31 +262,35 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
method_name.name
));
let self_ty_name = self
let mut self_ty_name = self
.sess()
.source_map()
.span_to_snippet(self_ty_span)
.unwrap_or_else(|_| self_ty.to_string());
let self_ty_generics_count = match self_ty.kind() {
// Get the number of generics the self type has (if an Adt) unless we can determine that
// the user has written the self type with generics already which we (naively) do by looking
// for a "<" in `self_ty_name`.
Adt(def, _) if !self_ty_name.contains('<') => self.tcx.generics_of(def.did).count(),
_ => 0,
};
let self_ty_generics = if self_ty_generics_count > 0 {
format!("<{}>", vec!["_"; self_ty_generics_count].join(", "))
} else {
String::new()
};
// Get the number of generics the self type has (if an Adt) unless we can determine that
// the user has written the self type with generics already which we (naively) do by looking
// for a "<" in `self_ty_name`.
if !self_ty_name.contains('<') {
if let Adt(def, _) = self_ty.kind() {
let generics = self.tcx.generics_of(def.did);
if !generics.params.is_empty() {
let counts = generics.own_counts();
self_ty_name += &format!(
"<{}>",
std::iter::repeat("'_")
.take(counts.lifetimes)
.chain(std::iter::repeat("_").take(counts.types + counts.consts))
.collect::<Vec<_>>()
.join(", ")
);
}
}
}
lint.span_suggestion(
span,
"disambiguate the associated function",
format!(
"<{}{} as {}>::{}",
self_ty_name, self_ty_generics, trait_name, method_name.name,
),
format!("<{} as {}>::{}", self_ty_name, trait_name, method_name.name,),
Applicability::MachineApplicable,
);