diff --git a/src/librustc_typeck/check/demand.rs b/src/librustc_typeck/check/demand.rs
index 08cf6d3a59ec5..4724a0fa51b97 100644
--- a/src/librustc_typeck/check/demand.rs
+++ b/src/librustc_typeck/check/demand.rs
@@ -134,10 +134,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
}
- if let Some(suggestion) = self.check_ref(expr,
- checked_ty,
- expected) {
- err.help(&suggestion);
+ if let Some((msg, suggestion)) = self.check_ref(expr, checked_ty, expected) {
+ err.span_suggestion(expr.span, msg, suggestion);
} else {
let mode = probe::Mode::MethodCall;
let suggestions = self.probe_for_return_type(syntax_pos::DUMMY_SP,
@@ -214,7 +212,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
expr: &hir::Expr,
checked_ty: Ty<'tcx>,
expected: Ty<'tcx>)
- -> Option<String> {
+ -> Option<(&'static str, String)> {
match (&expected.sty, &checked_ty.sty) {
(&ty::TyRef(_, exp), &ty::TyRef(_, check)) => match (&exp.ty.sty, &check.ty.sty) {
(&ty::TyStr, &ty::TyArray(arr, _)) |
@@ -222,7 +220,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
if let hir::ExprLit(_) = expr.node {
let sp = self.sess().codemap().call_span_if_macro(expr.span);
if let Ok(src) = self.tcx.sess.codemap().span_to_snippet(sp) {
- return Some(format!("try `{}`", &src[1..]));
+ return Some(("consider removing the leading `b`",
+ src[1..].to_string()));
}
}
None
@@ -232,7 +231,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
if let hir::ExprLit(_) = expr.node {
let sp = self.sess().codemap().call_span_if_macro(expr.span);
if let Ok(src) = self.tcx.sess.codemap().span_to_snippet(sp) {
- return Some(format!("try `b{}`", src));
+ return Some(("consider adding a leading `b`",
+ format!("b{}", src)));
}
}
None
@@ -260,12 +260,14 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// Use the callsite's span if this is a macro call. #41858
let sp = self.sess().codemap().call_span_if_macro(expr.span);
if let Ok(src) = self.tcx.sess.codemap().span_to_snippet(sp) {
- return Some(format!("try with `{}{}`",
- match mutability.mutbl {
- hir::Mutability::MutMutable => "&mut ",
- hir::Mutability::MutImmutable => "&",
- },
- &src));
+ return Some(match mutability.mutbl {
+ hir::Mutability::MutMutable => {
+ ("consider mutably borrowing here", format!("&mut {}", src))
+ }
+ hir::Mutability::MutImmutable => {
+ ("consider borrowing here", format!("&{}", src))
+ }
+ });
}
}
None
@@ -284,7 +286,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// Maybe remove `&`?
hir::ExprAddrOf(_, ref expr) => {
if let Ok(code) = self.tcx.sess.codemap().span_to_snippet(expr.span) {
- return Some(format!("try with `{}`", code));
+ return Some(("consider removing the borrow",
+ code));
}
}
@@ -295,7 +298,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
expr.span) {
let sp = self.sess().codemap().call_span_if_macro(expr.span);
if let Ok(code) = self.tcx.sess.codemap().span_to_snippet(sp) {
- return Some(format!("try with `*{}`", code));
+ return Some(("consider dereferencing the borrow",
+ format!("*{}", code)));
}
}
},
diff --git a/src/test/compile-fail/issue-13058.rs b/src/test/compile-fail/issue-13058.rs
index 590f8073a1a0d..27b23f083217d 100644
--- a/src/test/compile-fail/issue-13058.rs
+++ b/src/test/compile-fail/issue-13058.rs
@@ -35,5 +35,5 @@ fn check<'r, I: Iterator<Item=usize>, T: Itble<'r, usize, I>>(cont: &T) -> bool
fn main() {
check((3, 5));
//~^ ERROR mismatched types
-//~| HELP try with `&(3, 5)`
+//~| HELP consider borrowing here
}
diff --git a/src/test/ui/deref-suggestion.stderr b/src/test/ui/deref-suggestion.stderr
index 6c418cf4bfbed..98ec3d9693fb8 100644
--- a/src/test/ui/deref-suggestion.stderr
+++ b/src/test/ui/deref-suggestion.stderr
@@ -17,31 +17,37 @@ error[E0308]: mismatched types
--> $DIR/deref-suggestion.rs:23:10
|
23 | foo3(u); //~ ERROR mismatched types
- | ^ expected u32, found &u32
+ | ^
+ | |
+ | expected u32, found &u32
+ | help: consider dereferencing the borrow: `*u`
|
= note: expected type `u32`
found type `&u32`
- = help: try with `*u`
error[E0308]: mismatched types
--> $DIR/deref-suggestion.rs:30:9
|
30 | foo(&"aaa".to_owned()); //~ ERROR mismatched types
- | ^^^^^^^^^^^^^^^^^ expected struct `std::string::String`, found reference
+ | ^^^^^^^^^^^^^^^^^
+ | |
+ | expected struct `std::string::String`, found reference
+ | help: consider removing the borrow: `"aaa".to_owned()`
|
= note: expected type `std::string::String`
found type `&std::string::String`
- = help: try with `"aaa".to_owned()`
error[E0308]: mismatched types
--> $DIR/deref-suggestion.rs:31:9
|
31 | foo(&mut "aaa".to_owned()); //~ ERROR mismatched types
- | ^^^^^^^^^^^^^^^^^^^^^ expected struct `std::string::String`, found mutable reference
+ | ^^^^^^^^^^^^^^^^^^^^^
+ | |
+ | expected struct `std::string::String`, found mutable reference
+ | help: consider removing the borrow: `"aaa".to_owned()`
|
= note: expected type `std::string::String`
found type `&mut std::string::String`
- = help: try with `"aaa".to_owned()`
error[E0308]: mismatched types
--> $DIR/deref-suggestion.rs:12:20
diff --git a/src/test/ui/span/coerce-suggestions.rs b/src/test/ui/span/coerce-suggestions.rs
index a1a250b0e9ad2..0a3e18043fe45 100644
--- a/src/test/ui/span/coerce-suggestions.rs
+++ b/src/test/ui/span/coerce-suggestions.rs
@@ -23,7 +23,7 @@ fn main() {
//~^ ERROR E0308
//~| NOTE expected &str, found struct `std::string::String`
//~| NOTE expected type `&str`
- //~| HELP try with `&String::new()`
+ //~| HELP consider borrowing here
let y = String::new();
test(&y);
//~^ ERROR E0308
diff --git a/src/test/ui/span/coerce-suggestions.stderr b/src/test/ui/span/coerce-suggestions.stderr
index 98ea34fd992c8..604b38bef6cc4 100644
--- a/src/test/ui/span/coerce-suggestions.stderr
+++ b/src/test/ui/span/coerce-suggestions.stderr
@@ -14,11 +14,13 @@ error[E0308]: mismatched types
--> $DIR/coerce-suggestions.rs:22:19
|
22 | let x: &str = String::new();
- | ^^^^^^^^^^^^^ expected &str, found struct `std::string::String`
+ | ^^^^^^^^^^^^^
+ | |
+ | expected &str, found struct `std::string::String`
+ | help: consider borrowing here: `&String::new()`
|
= note: expected type `&str`
found type `std::string::String`
- = help: try with `&String::new()`
error[E0308]: mismatched types
--> $DIR/coerce-suggestions.rs:28:10
@@ -48,11 +50,13 @@ error[E0308]: mismatched types
--> $DIR/coerce-suggestions.rs:42:9
|
42 | s = format!("foo");
- | ^^^^^^^^^^^^^^ expected mutable reference, found struct `std::string::String`
+ | ^^^^^^^^^^^^^^
+ | |
+ | expected mutable reference, found struct `std::string::String`
+ | help: consider mutably borrowing here: `&mut format!("foo")`
|
= note: expected type `&mut std::string::String`
found type `std::string::String`
- = help: try with `&mut format!("foo")`
= note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
error: aborting due to 6 previous errors
diff --git a/src/test/ui/str-lit-type-mismatch.stderr b/src/test/ui/str-lit-type-mismatch.stderr
index bf7646d81eb1d..b232bf74666b1 100644
--- a/src/test/ui/str-lit-type-mismatch.stderr
+++ b/src/test/ui/str-lit-type-mismatch.stderr
@@ -2,31 +2,37 @@ error[E0308]: mismatched types
--> $DIR/str-lit-type-mismatch.rs:13:20
|
13 | let x: &[u8] = "foo"; //~ ERROR mismatched types
- | ^^^^^ expected slice, found str
+ | ^^^^^
+ | |
+ | expected slice, found str
+ | help: consider adding a leading `b`: `b"foo"`
|
= note: expected type `&[u8]`
found type `&'static str`
- = help: try `b"foo"`
error[E0308]: mismatched types
--> $DIR/str-lit-type-mismatch.rs:14:23
|
14 | let y: &[u8; 4] = "baaa"; //~ ERROR mismatched types
- | ^^^^^^ expected array of 4 elements, found str
+ | ^^^^^^
+ | |
+ | expected array of 4 elements, found str
+ | help: consider adding a leading `b`: `b"baaa"`
|
= note: expected type `&[u8; 4]`
found type `&'static str`
- = help: try `b"baaa"`
error[E0308]: mismatched types
--> $DIR/str-lit-type-mismatch.rs:15:19
|
15 | let z: &str = b"foo"; //~ ERROR mismatched types
- | ^^^^^^ expected str, found array of 3 elements
+ | ^^^^^^
+ | |
+ | expected str, found array of 3 elements
+ | help: consider removing the leading `b`: `"foo"`
|
= note: expected type `&str`
found type `&'static [u8; 3]`
- = help: try `"foo"`
error: aborting due to 3 previous errors
diff --git a/src/test/ui/suggestions/str-array-assignment.rs b/src/test/ui/suggestions/str-array-assignment.rs
index 6c7f4852a4ae5..444684507d387 100644
--- a/src/test/ui/suggestions/str-array-assignment.rs
+++ b/src/test/ui/suggestions/str-array-assignment.rs
@@ -28,5 +28,5 @@ fn main() { //~ NOTE expected `()` because of default return type
//~^ ERROR mismatched types
//~| NOTE expected &str, found str
//~| NOTE expected type
- //~| HELP try with `&s[..2]`
+ //~| HELP consider borrowing here
}
diff --git a/src/test/ui/suggestions/str-array-assignment.stderr b/src/test/ui/suggestions/str-array-assignment.stderr
index 14b744c2e469c..c65639805af6c 100644
--- a/src/test/ui/suggestions/str-array-assignment.stderr
+++ b/src/test/ui/suggestions/str-array-assignment.stderr
@@ -34,11 +34,13 @@ error[E0308]: mismatched types
--> $DIR/str-array-assignment.rs:27:17
|
27 | let w: &str = s[..2];
- | ^^^^^^ expected &str, found str
+ | ^^^^^^
+ | |
+ | expected &str, found str
+ | help: consider borrowing here: `&s[..2]`
|
= note: expected type `&str`
found type `str`
- = help: try with `&s[..2]`
error: aborting due to 4 previous errors