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suggestion-diagnostics: as_ref improve snippet

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Improve the code snippet suggested in suggestion-diagnostics when
suggesting the use of as_ref.
This commit is contained in:
Dan Robertson 2019-02-13 17:52:22 +00:00
parent e544947278
commit 285d4a7eb6
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GPG key ID: 45C4A652C47E42A5
2 changed files with 18 additions and 13 deletions
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15
src/librustc_typeck/check/demand.rs
View file

@ -210,7 +210,10 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
/// ```
/// opt.map(|arg| { takes_ref(arg) });
/// ```
fn can_use_as_ref(&self, expr: &hir::Expr) -> Option<(Span, &'static str, String)> {
fn can_use_as_ref(
&self,
expr: &hir::Expr,
) -> Option<(Span, &'static str, String)> {
if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.node {
if let hir::def::Def::Local(id) = path.def {
let parent = self.tcx.hir().get_parent_node(id);
@ -233,10 +236,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
self_ty.starts_with("std::option::Option") ||
self_ty.starts_with("std::result::Result")
) && (name == "map" || name == "and_then");
if is_as_ref_able {
return Some((span.shrink_to_lo(),
"consider using `as_ref` instead",
"as_ref().".into()));
match (is_as_ref_able, self.sess().source_map().span_to_snippet(*span)) {
(true, Ok(src)) => {
return Some((*span, "consider using `as_ref` instead",
format!("as_ref().{}", src)));
},
_ => ()
}
}
}

16
src/test/ui/suggestions/as-ref.stderr
View file

@ -2,9 +2,9 @@ error[E0308]: mismatched types
--> $DIR/as-ref.rs:6:27
|
LL | opt.map(|arg| takes_ref(arg));
| - ^^^ expected &Foo, found struct `Foo`
| --- ^^^ expected &Foo, found struct `Foo`
| |
| help: consider using `as_ref` instead: `as_ref().`
| help: consider using `as_ref` instead: `as_ref().map`
|
= note: expected type `&Foo`
found type `Foo`
@ -13,9 +13,9 @@ error[E0308]: mismatched types
--> $DIR/as-ref.rs:8:37
|
LL | opt.and_then(|arg| Some(takes_ref(arg)));
| - ^^^ expected &Foo, found struct `Foo`
| -------- ^^^ expected &Foo, found struct `Foo`
| |
| help: consider using `as_ref` instead: `as_ref().`
| help: consider using `as_ref` instead: `as_ref().and_then`
|
= note: expected type `&Foo`
found type `Foo`
@ -24,9 +24,9 @@ error[E0308]: mismatched types
--> $DIR/as-ref.rs:11:27
|
LL | opt.map(|arg| takes_ref(arg));
| - ^^^ expected &Foo, found struct `Foo`
| --- ^^^ expected &Foo, found struct `Foo`
| |
| help: consider using `as_ref` instead: `as_ref().`
| help: consider using `as_ref` instead: `as_ref().map`
|
= note: expected type `&Foo`
found type `Foo`
@ -35,9 +35,9 @@ error[E0308]: mismatched types
--> $DIR/as-ref.rs:13:35
|
LL | opt.and_then(|arg| Ok(takes_ref(arg)));
| - ^^^ expected &Foo, found struct `Foo`
| -------- ^^^ expected &Foo, found struct `Foo`
| |
| help: consider using `as_ref` instead: `as_ref().`
| help: consider using `as_ref` instead: `as_ref().and_then`
|
= note: expected type `&Foo`
found type `Foo`