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| author | Mazdak Farrokhzad <twingoow@gmail.com> | 2019-02-14 02:41:15 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-02-14 02:41:15 +0100 |
| commit | 93ecae63d89f66af6029a002b2269e6fb3687dd4 (patch) | |
| tree | 098b268f58da59c4fd385b6e8e4bb860ef36984a /src | |
| parent | 4772dc8087b1d0f2bab6d064fd930e596c82d439 (diff) | |
| parent | 285d4a7eb67cdf3ebba4b8fe60a5c5a6abf3edfc (diff) | |
| download | rust-93ecae63d89f66af6029a002b2269e6fb3687dd4.tar.gz rust-93ecae63d89f66af6029a002b2269e6fb3687dd4.zip | |
Rollup merge of #57451 - dlrobertson:can_use_as_ref_nit, r=estebank
suggestion-diagnostics: as_ref improve snippet
Improve the code snippet suggested in suggestion-diagnostics when
suggesting the use of as_ref.
Given:
```rust
fn test(x: &usize) {}
fn main() {
Some(42).map(|x| test(x));
}
```
Suggest
```
help: consider using `as_ref` instead: `as_ref().map`
```
Instead of
```
help: consider using `as_ref` instead: `as_ref().`
```
Diffstat (limited to 'src')
| -rw-r--r-- | src/librustc_typeck/check/demand.rs | 15 | ||||
| -rw-r--r-- | src/test/ui/suggestions/as-ref.stderr | 16 |
2 files changed, 18 insertions, 13 deletions
diff --git a/src/librustc_typeck/check/demand.rs b/src/librustc_typeck/check/demand.rs index 33e93b582e5..bb9fc872b85 100644 --- a/src/librustc_typeck/check/demand.rs +++ b/src/librustc_typeck/check/demand.rs @@ -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))); + }, + _ => () } } } diff --git a/src/test/ui/suggestions/as-ref.stderr b/src/test/ui/suggestions/as-ref.stderr index 7273496a7ce..8143acc957b 100644 --- a/src/test/ui/suggestions/as-ref.stderr +++ b/src/test/ui/suggestions/as-ref.stderr @@ -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` |