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Lint elided lifetimes in path on the AST.

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This commit is contained in:
Camille GILLOT
2022-03-10 23:12:35 +01:00
parent ca57bada05
commit a9e13fa553
24 changed files with 279 additions and 154 deletions
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39
compiler/rustc_ast_lowering/src/path.rs
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@@ -290,47 +290,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
generic_args.span.with_lo(generic_args.span.lo() + BytePos(1)).shrink_to_lo()
};
generic_args.args = self
.elided_path_lifetimes(elided_lifetime_span, expected_lifetimes, param_mode)
.elided_path_lifetimes(elided_lifetime_span, expected_lifetimes)
.map(GenericArg::Lifetime)
.chain(generic_args.args.into_iter())
.collect();
// In create-parameter mode we error here because we don't want to support
// deprecated impl elision in new features like impl elision and `async fn`,
// both of which work using the `CreateParameter` mode:
//
// impl Foo for std::cell::Ref<u32> // note lack of '_
// async fn foo(_: std::cell::Ref<u32>) { ... }
if let (ParamMode::Explicit, AnonymousLifetimeMode::CreateParameter) =
(param_mode, self.anonymous_lifetime_mode)
{
let anon_lt_suggestion = vec!["'_"; expected_lifetimes].join(", ");
let no_non_lt_args = generic_args.args.len() == expected_lifetimes;
let no_bindings = generic_args.bindings.is_empty();
let (incl_angl_brckt, suggestion) = if no_non_lt_args && no_bindings {
// If there are no generic args, our suggestion can include the angle brackets.
(true, format!("<{}>", anon_lt_suggestion))
} else {
// Otherwise we'll insert a `'_, ` right after the opening bracket.
(false, format!("{}, ", anon_lt_suggestion))
};
let insertion_sp = elided_lifetime_span.shrink_to_hi();
let mut err = struct_span_err!(
self.sess,
path_span,
E0726,
"implicit elided lifetime not allowed here"
);
rustc_errors::add_elided_lifetime_in_path_suggestion(
&self.sess.source_map(),
&mut err,
expected_lifetimes,
path_span,
incl_angl_brckt,
insertion_sp,
suggestion,
);
err.note("assuming a `'static` lifetime...");
err.emit();
// Late resolver should have issued the error.
self.sess
.delay_span_bug(elided_lifetime_span, "implicit lifetime not allowed here");
}
}