diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index 0434c1ba59a..86e577fdf1d 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -229,15 +229,15 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
} => {
err.span_label(span, format!("cannot {ACT}", ACT = act));
- if let Some((span, message)) = annotate_struct_field(
+ if let Some(span) = get_mut_span_in_struct_field(
self.infcx.tcx,
Place::ty_from(local, proj_base, self.body, self.infcx.tcx).ty,
field,
) {
- err.span_suggestion(
+ err.span_suggestion_verbose(
span,
"consider changing this to be mutable",
- message,
+ "mut ".into(),
Applicability::MaybeIncorrect,
);
}
@@ -1059,18 +1059,18 @@ fn is_closure_or_generator(ty: Ty<'_>) -> bool {
ty.is_closure() || ty.is_generator()
}
-/// Adds a suggestion to a struct definition given a field access to a local.
-/// This function expects the local to be a reference to a struct in order to produce a suggestion.
+/// Given a field that needs to be mutuable, returns a span where the mut could go.
+/// This function expects the local to be a reference to a struct in order to produce a span.
///
/// ```text
/// LL | s: &'a String
-/// | ---------- use `&'a mut String` here to make mutable
+/// | ^ returns a span pointing here
/// ```
-fn annotate_struct_field<'tcx>(
+fn get_mut_span_in_struct_field<'tcx>(
tcx: TyCtxt<'tcx>,
ty: Ty<'tcx>,
field: &mir::Field,
-) -> Option<(Span, String)> {
+) -> Option<Span> {
// Expect our local to be a reference to a struct of some kind.
if let ty::Ref(_, ty, _) = ty.kind() {
if let ty::Adt(def, _) = ty.kind() {
@@ -1081,25 +1081,12 @@ fn annotate_struct_field<'tcx>(
// Now we're dealing with the actual struct that we're going to suggest a change to,
// we can expect a field that is an immutable reference to a type.
if let hir::Node::Field(field) = node {
- if let hir::TyKind::Rptr(
- lifetime,
- hir::MutTy { mutbl: hir::Mutability::Not, ref ty },
- ) = field.ty.kind
+ if let hir::TyKind::Rptr(lifetime, hir::MutTy { mutbl: hir::Mutability::Not, .. }) =
+ field.ty.kind
{
- // Get the snippets in two parts - the named lifetime (if there is one) and
- // type being referenced, that way we can reconstruct the snippet without loss
- // of detail.
- let type_snippet = tcx.sess.source_map().span_to_snippet(ty.span).ok()?;
- let lifetime_snippet = if !lifetime.is_elided() {
- format!("{} ", tcx.sess.source_map().span_to_snippet(lifetime.span).ok()?)
- } else {
- String::new()
- };
-
- return Some((
- field.ty.span,
- format!("&{}mut {}", lifetime_snippet, &*type_snippet,),
- ));
+ return Some(
+ lifetime.span.with_hi(lifetime.span.hi() + BytePos(1)).shrink_to_hi(),
+ );
}
}
}
diff --git a/src/test/ui/did_you_mean/issue-38147-2.rs b/src/test/ui/did_you_mean/issue-38147-2.rs
index fe2634d88ab..154b149b720 100644
--- a/src/test/ui/did_you_mean/issue-38147-2.rs
+++ b/src/test/ui/did_you_mean/issue-38147-2.rs
@@ -1,11 +1,16 @@
struct Bar<'a> {
- s: &'a String
+ s: &'a String,
+ // use wonky spaces to ensure we are creating the span correctly
+ longer_name: & 'a Vec<u8>
}
impl<'a> Bar<'a> {
fn f(&mut self) {
self.s.push('x');
//~^ ERROR cannot borrow `*self.s` as mutable, as it is behind a `&` reference
+
+ self.longer_name.push(13);
+ //~^ ERROR cannot borrow `*self.longer_name` as mutable, as it is behind a `&` reference
}
}
diff --git a/src/test/ui/did_you_mean/issue-38147-2.stderr b/src/test/ui/did_you_mean/issue-38147-2.stderr
index 8bf5c76977d..5ff97eacc23 100644
--- a/src/test/ui/did_you_mean/issue-38147-2.stderr
+++ b/src/test/ui/did_you_mean/issue-38147-2.stderr
@@ -1,12 +1,25 @@
error[E0596]: cannot borrow `*self.s` as mutable, as it is behind a `&` reference
- --> $DIR/issue-38147-2.rs:7:9
+ --> $DIR/issue-38147-2.rs:9:9
|
-LL | s: &'a String
- | ---------- help: consider changing this to be mutable: `&'a mut String`
-...
LL | self.s.push('x');
| ^^^^^^^^^^^^^^^^ cannot borrow as mutable
+ |
+help: consider changing this to be mutable
+ |
+LL | s: &'a mut String,
+ | +++
-error: aborting due to previous error
+error[E0596]: cannot borrow `*self.longer_name` as mutable, as it is behind a `&` reference
+ --> $DIR/issue-38147-2.rs:12:9
+ |
+LL | self.longer_name.push(13);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^ cannot borrow as mutable
+ |
+help: consider changing this to be mutable
+ |
+LL | longer_name: & 'a mut Vec<u8>
+ | +++
+
+error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0596`.
diff --git a/src/test/ui/did_you_mean/issue-38147-3.stderr b/src/test/ui/did_you_mean/issue-38147-3.stderr
index 0e1e42261c4..94ffe17f101 100644
--- a/src/test/ui/did_you_mean/issue-38147-3.stderr
+++ b/src/test/ui/did_you_mean/issue-38147-3.stderr
@@ -1,11 +1,13 @@
error[E0596]: cannot borrow `*self.s` as mutable, as it is behind a `&` reference
--> $DIR/issue-38147-3.rs:7:9
|
-LL | s: &'a String
- | ---------- help: consider changing this to be mutable: `&'a mut String`
-...
LL | self.s.push('x');
| ^^^^^^^^^^^^^^^^ cannot borrow as mutable
+ |
+help: consider changing this to be mutable
+ |
+LL | s: &'a mut String
+ | +++
error: aborting due to previous error