diff --git a/src/librustc_typeck/check/demand.rs b/src/librustc_typeck/check/demand.rs index f736e7ac29d08..32ca854b27744 100644 --- a/src/librustc_typeck/check/demand.rs +++ b/src/librustc_typeck/check/demand.rs @@ -367,6 +367,15 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { // Maybe remove `&`? hir::ExprKind::AddrOf(_, ref expr) => { if !cm.span_to_filename(expr.span).is_real() { + if let Ok(code) = cm.span_to_snippet(sp) { + if code.chars().next() == Some('&') { + return Some(( + sp, + "consider removing the borrow", + code[1..].to_string()), + ); + } + } return None; } if let Ok(code) = cm.span_to_snippet(expr.span) { diff --git a/src/test/ui/block-result/issue-5500.stderr b/src/test/ui/block-result/issue-5500.stderr index 0d9c9d8143d31..6a13b31fe932f 100644 --- a/src/test/ui/block-result/issue-5500.stderr +++ b/src/test/ui/block-result/issue-5500.stderr @@ -4,7 +4,10 @@ error[E0308]: mismatched types LL | fn main() { | - expected `()` because of default return type LL | &panic!() - | ^^^^^^^^^ expected (), found reference + | ^^^^^^^^^ + | | + | expected (), found reference + | help: consider removing the borrow: `panic!()` | = note: expected type `()` found type `&_` diff --git a/src/test/ui/diverging-tuple-parts-39485.stderr b/src/test/ui/diverging-tuple-parts-39485.stderr index c399650d3258b..3457549a75239 100644 --- a/src/test/ui/diverging-tuple-parts-39485.stderr +++ b/src/test/ui/diverging-tuple-parts-39485.stderr @@ -1,13 +1,19 @@ error[E0308]: mismatched types --> $DIR/diverging-tuple-parts-39485.rs:8:5 | -LL | fn g() { - | - help: try adding a return type: `-> &_` LL | &panic!() //~ ERROR mismatched types | ^^^^^^^^^ expected (), found reference | = note: expected type `()` found type `&_` +help: try adding a return type + | +LL | fn g() -> &_ { + | ^^^^^ +help: consider removing the borrow + | +LL | panic!() //~ ERROR mismatched types + | ^^^^^^^^ error[E0308]: mismatched types --> $DIR/diverging-tuple-parts-39485.rs:12:5 diff --git a/src/test/ui/suggestions/format-borrow.rs b/src/test/ui/suggestions/format-borrow.rs new file mode 100644 index 0000000000000..63930e7f787fd --- /dev/null +++ b/src/test/ui/suggestions/format-borrow.rs @@ -0,0 +1,6 @@ +fn main() { + let a: String = &String::from("a"); + //~^ ERROR mismatched types + let b: String = &format!("b"); + //~^ ERROR mismatched types +} diff --git a/src/test/ui/suggestions/format-borrow.stderr b/src/test/ui/suggestions/format-borrow.stderr new file mode 100644 index 0000000000000..44bb11faa7f38 --- /dev/null +++ b/src/test/ui/suggestions/format-borrow.stderr @@ -0,0 +1,27 @@ +error[E0308]: mismatched types + --> $DIR/format-borrow.rs:2:21 + | +LL | let a: String = &String::from("a"); + | ^^^^^^^^^^^^^^^^^^ + | | + | expected struct `std::string::String`, found reference + | help: consider removing the borrow: `String::from("a")` + | + = note: expected type `std::string::String` + found type `&std::string::String` + +error[E0308]: mismatched types + --> $DIR/format-borrow.rs:4:21 + | +LL | let b: String = &format!("b"); + | ^^^^^^^^^^^^^ + | | + | expected struct `std::string::String`, found reference + | help: consider removing the borrow: `format!("b")` + | + = note: expected type `std::string::String` + found type `&std::string::String` + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0308`.