bjoernager/rust
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Only suggest 1-tuple if expected and found types match

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This commit is contained in:
Rob Pilling 2022-01-28 23:17:47 +00:00
parent 18cea90d4a
commit 91a43f0423
2 changed files with 27 additions and 23 deletions
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46
compiler/rustc_infer/src/infer/error_reporting/mod.rs
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@ -2044,26 +2044,34 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
// If a tuple of length one was expected and the found expression has
// parentheses around it, perhaps the user meant to write `(expr,)` to
// build a tuple (issue #86100)
(ty::Tuple(_), _) if expected.tuple_fields().count() == 1 => {
if let Ok(code) = self.tcx.sess().source_map().span_to_snippet(span) {
if code.starts_with('(') && code.ends_with(')') {
let before_close = span.hi() - BytePos::from_u32(1);
(ty::Tuple(_), _) => {
if let [expected_tup_elem] =
expected.tuple_fields().collect::<Vec<_>>()[..]
{
if same_type_modulo_infer(expected_tup_elem, found) {
if let Ok(code) =
self.tcx.sess().source_map().span_to_snippet(span)
{
if code.starts_with('(') && code.ends_with(')') {
let before_close = span.hi() - BytePos::from_u32(1);
err.span_suggestion(
span.with_hi(before_close).shrink_to_hi(),
"use a trailing comma to create a tuple with one element",
",".into(),
Applicability::MaybeIncorrect,
);
} else {
err.multipart_suggestion(
"use a trailing comma to create a tuple with one element",
vec![
(span.shrink_to_lo(), "(".into()),
(span.shrink_to_hi(), ",)".into()),
],
Applicability::MaybeIncorrect,
);
err.span_suggestion(
span.with_hi(before_close).shrink_to_hi(),
"use a trailing comma to create a tuple with one element",
",".into(),
Applicability::MaybeIncorrect,
);
} else {
err.multipart_suggestion(
"use a trailing comma to create a tuple with one element",
vec![
(span.shrink_to_lo(), "(".into()),
(span.shrink_to_hi(), ",)".into()),
],
Applicability::MaybeIncorrect,
);
}
}
}
}
}