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Account for impl Trait
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estebank committed Feb 5, 2020
1 parent 1beac2b commit 96bbb0d
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Showing 3 changed files with 71 additions and 34 deletions.
89 changes: 55 additions & 34 deletions src/librustc_resolve/diagnostics.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1519,9 +1519,21 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
for missing in &self.missing_named_lifetime_spots {
match missing {
MissingLifetimeSpot::Generics(generics) => {
let (span, sugg) = match &generics.params {
[] => (generics.span, format!("<{}>", lifetime_ref)),
[param, ..] => (param.span.shrink_to_lo(), format!("{}, ", lifetime_ref)),
let (span, sugg) = if let Some(param) = generics
.params
.iter()
.filter(|p| match p.kind {
hir::GenericParamKind::Type {
synthetic: Some(hir::SyntheticTyParamKind::ImplTrait),
..
} => false,
_ => true,
})
.next()
{
(param.span.shrink_to_lo(), format!("{}, ", lifetime_ref))
} else {
(generics.span, format!("<{}>", lifetime_ref))
};
err.span_suggestion(
span,
Expand Down Expand Up @@ -1592,20 +1604,28 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
Applicability::MaybeIncorrect,
);
};
let suggest_new = |err: &mut DiagnosticBuilder<'_>, sugg: &str| {
err.span_label(span, "expected named lifetime parameter");

for missing in self.missing_named_lifetime_spots.iter().rev() {
let mut introduce_suggestion = vec![];
let msg;
let should_break;
introduce_suggestion.push(match missing {
let suggest_new =
|err: &mut DiagnosticBuilder<'_>, sugg: &str| {
err.span_label(span, "expected named lifetime parameter");

for missing in self.missing_named_lifetime_spots.iter().rev() {
let mut introduce_suggestion = vec![];
let msg;
let should_break;
introduce_suggestion.push(match missing {
MissingLifetimeSpot::Generics(generics) => {
msg = "consider introducing a named lifetime parameter".to_string();
should_break = true;
match &generics.params {
[] => (generics.span, "<'a>".to_string()),
[param, ..] => (param.span.shrink_to_lo(), "'a, ".to_string()),
if let Some(param) = generics.params.iter().filter(|p| match p.kind {
hir::GenericParamKind::Type {
synthetic: Some(hir::SyntheticTyParamKind::ImplTrait),
..
} => false,
_ => true,
}).next() {
(param.span.shrink_to_lo(), "'a, ".to_string())
} else {
(generics.span, "<'a>".to_string())
}
}
MissingLifetimeSpot::HigherRanked { span, span_type } => {
Expand All @@ -1621,29 +1641,30 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
(*span, span_type.suggestion("'a"))
}
});
for param in params {
if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(param.span)
{
if snippet.starts_with("&") && !snippet.starts_with("&'") {
introduce_suggestion
.push((param.span, format!("&'a {}", &snippet[1..])));
} else if snippet.starts_with("&'_ ") {
introduce_suggestion
.push((param.span, format!("&'a {}", &snippet[4..])));
for param in params {
if let Ok(snippet) =
self.tcx.sess.source_map().span_to_snippet(param.span)
{
if snippet.starts_with("&") && !snippet.starts_with("&'") {
introduce_suggestion
.push((param.span, format!("&'a {}", &snippet[1..])));
} else if snippet.starts_with("&'_ ") {
introduce_suggestion
.push((param.span, format!("&'a {}", &snippet[4..])));
}
}
}
introduce_suggestion.push((span, sugg.to_string()));
err.multipart_suggestion(
&msg,
introduce_suggestion,
Applicability::MaybeIncorrect,
);
if should_break {
break;
}
}
introduce_suggestion.push((span, sugg.to_string()));
err.multipart_suggestion(
&msg,
introduce_suggestion,
Applicability::MaybeIncorrect,
);
if should_break {
break;
}
}
};
};

match (
lifetime_names.len(),
Expand Down
2 changes: 2 additions & 0 deletions src/test/ui/suggestions/impl-trait-missing-lifetime.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
fn f(_: impl Iterator<Item = &'_ ()>) {} //~ ERROR missing lifetime specifier
fn main() {}
14 changes: 14 additions & 0 deletions src/test/ui/suggestions/impl-trait-missing-lifetime.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,14 @@
error[E0106]: missing lifetime specifier
--> $DIR/impl-trait-missing-lifetime.rs:1:31
|
LL | fn f(_: impl Iterator<Item = &'_ ()>) {}
| ^^ expected named lifetime parameter
|
help: consider introducing a named lifetime parameter
|
LL | fn f<'a>(_: impl Iterator<Item = &'a ()>) {}
| ^^^^ ^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0106`.

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