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Account for typo in turbofish and suggest ::

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This commit is contained in:
Esteban Küber 2019-11-05 10:29:54 -08:00
parent 3bbfc7320b
commit a8ccbf5f2f
2 changed files with 11 additions and 5 deletions
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14
src/libsyntax/parse/parser/diagnostics.rs
View file

@ -358,7 +358,7 @@ impl<'a> Parser<'a> {
err: &mut DiagnosticBuilder<'_>,
maybe_expected_semicolon: bool,
) {
if let Some((sp, likely_path)) = self.last_type_ascription {
if let Some((sp, likely_path)) = self.last_type_ascription.take() {
let sm = self.sess.source_map();
let next_pos = sm.lookup_char_pos(self.token.span.lo());
let op_pos = sm.lookup_char_pos(sp.hi());
@ -395,7 +395,6 @@ impl<'a> Parser<'a> {
err.note("for more information, see \
https://github.com/rust-lang/rust/issues/23416");
}
self.last_type_ascription = None;
}
}
@ -1083,8 +1082,15 @@ impl<'a> Parser<'a> {
}
pub(super) fn could_ascription_be_path(&self, node: &ast::ExprKind) -> bool {
self.token.is_ident() &&
if let ast::ExprKind::Path(..) = node { true } else { false } &&
(self.token == token::Lt && // `foo:<bar`, likely a typoed turbofish.
self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident())
) ||
self.token.is_ident() &&
match node {
// `foo::` → `foo:` or `foo.bar::` → `foo.bar:`
ast::ExprKind::Path(..) | ast::ExprKind::Field(..) => true,
_ => false,
} &&
!self.token.is_reserved_ident() && // v `foo:bar(baz)`
self.look_ahead(1, |t| t == &token::OpenDelim(token::Paren)) ||
self.look_ahead(1, |t| t == &token::Lt) && // `foo:bar<baz`

2
src/test/ui/suggestions/type-ascription-instead-of-path-2.stderr
View file

@ -4,7 +4,7 @@ error: expected `::`, found `(`
LL | vec![Ok(2)].into_iter().collect:<Result<Vec<_>,_>>()?;
| - ^ expected `::`
| |
| tried to parse a type due to this type ascription
| help: maybe write a path separator here: `::`
|
= note: `#![feature(type_ascription)]` lets you annotate an expression with a type: `<expr>: <type>`
= note: for more information, see https://github.com/rust-lang/rust/issues/23416