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Fix bad diagnostics for anon params with ref

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This commit is contained in:
Yuki Okushi 2021-03-05 04:19:15 +09:00
parent f5d8117c33
commit ea355bc6be
4 changed files with 96 additions and 35 deletions
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85
compiler/rustc_parse/src/parser/diagnostics.rs
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@ -1613,42 +1613,65 @@ impl<'a> Parser<'a> {
Applicability::HasPlaceholders,
);
return Some(ident);
} else if let PatKind::Ident(_, ident, _) = pat.kind {
if require_name
&& (self.token == token::Comma
|| self.token == token::Lt
|| self.token == token::CloseDelim(token::Paren))
{
// `fn foo(a, b) {}`, `fn foo(a<x>, b<y>) {}` or `fn foo(usize, usize) {}`
if first_param {
err.span_suggestion(
pat.span,
"if this is a `self` type, give it a parameter name",
format!("self: {}", ident),
Applicability::MaybeIncorrect,
);
}
// Avoid suggesting that `fn foo(HashMap<u32>)` is fixed with a change to
// `fn foo(HashMap: TypeName<u32>)`.
if self.token != token::Lt {
err.span_suggestion(
pat.span,
"if this is a parameter name, give it a type",
format!("{}: TypeName", ident),
Applicability::HasPlaceholders,
);
} else if require_name
&& (self.token == token::Comma
|| self.token == token::Lt
|| self.token == token::CloseDelim(token::Paren))
{
let (ident, self_sugg, param_sugg, type_sugg) = match pat.kind {
PatKind::Ident(_, ident, _) => (
ident,
format!("self: {}", ident),
format!("{}: TypeName", ident),
format!("_: {}", ident),
),
// Also catches `fn foo(&a)`.
PatKind::Ref(ref pat, mutab) => {
if let PatKind::Ident(_, ident, _) = pat.clone().into_inner().kind {
let mutab = mutab.prefix_str();
(
ident,
format!("self: &{}{}", mutab, ident),
format!("{}: &{}TypeName", ident, mutab),
format!("_: &{}{}", mutab, ident),
)
} else {
return None;
}
}
// Ignore other `PatKind`.
_ => return None,
};
// `fn foo(a, b) {}`, `fn foo(a<x>, b<y>) {}` or `fn foo(usize, usize) {}`
if first_param {
err.span_suggestion(
pat.span,
"if this is a type, explicitly ignore the parameter name",
format!("_: {}", ident),
Applicability::MachineApplicable,
"if this is a `self` type, give it a parameter name",
self_sugg,
Applicability::MaybeIncorrect,
);
err.note("anonymous parameters are removed in the 2018 edition (see RFC 1685)");
// Don't attempt to recover by using the `X` in `X<Y>` as the parameter name.
return if self.token == token::Lt { None } else { Some(ident) };
}
// Avoid suggesting that `fn foo(HashMap<u32>)` is fixed with a change to
// `fn foo(HashMap: TypeName<u32>)`.
if self.token != token::Lt {
err.span_suggestion(
pat.span,
"if this is a parameter name, give it a type",
param_sugg,
Applicability::HasPlaceholders,
);
}
err.span_suggestion(
pat.span,
"if this is a type, explicitly ignore the parameter name",
type_sugg,
Applicability::MachineApplicable,
);
err.note("anonymous parameters are removed in the 2018 edition (see RFC 1685)");
// Don't attempt to recover by using the `X` in `X<Y>` as the parameter name.
return if self.token == token::Lt { None } else { Some(ident) };
}
None
}