diff options
| -rw-r--r-- | compiler/rustc_hir_typeck/src/cast.rs | 10 | ||||
| -rw-r--r-- | tests/ui/cast/func-pointer-issue-140491.stderr | 2 | ||||
| -rw-r--r-- | tests/ui/coercion/issue-73886.stderr | 2 |
3 files changed, 14 insertions, 0 deletions
diff --git a/compiler/rustc_hir_typeck/src/cast.rs b/compiler/rustc_hir_typeck/src/cast.rs index c044c4f7c37..e144a6ab599 100644 --- a/compiler/rustc_hir_typeck/src/cast.rs +++ b/compiler/rustc_hir_typeck/src/cast.rs @@ -408,6 +408,16 @@ impl<'a, 'tcx> CastCheck<'tcx> { self.expr_ty, fcx.ty_to_string(self.cast_ty) ); + + if let Ok(snippet) = fcx.tcx.sess.source_map().span_to_snippet(self.expr_span) + && matches!(self.expr.kind, ExprKind::AddrOf(..)) + { + err.note(format!( + "casting reference expression `{}` because `&` binds tighter than `as`", + snippet + )); + } + let mut sugg = None; let mut sugg_mutref = false; if let ty::Ref(reg, cast_ty, mutbl) = *self.cast_ty.kind() { diff --git a/tests/ui/cast/func-pointer-issue-140491.stderr b/tests/ui/cast/func-pointer-issue-140491.stderr index ebd4b18502e..e1c07010e69 100644 --- a/tests/ui/cast/func-pointer-issue-140491.stderr +++ b/tests/ui/cast/func-pointer-issue-140491.stderr @@ -3,6 +3,8 @@ error[E0605]: non-primitive cast: `&for<'a, 'b> fn(&'a Event<'b>) {my_fn}` as `& | LL | ..._>) = &my_fn as _; | ^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object + | + = note: casting reference expression `&my_fn` because `&` binds tighter than `as` error: aborting due to 1 previous error diff --git a/tests/ui/coercion/issue-73886.stderr b/tests/ui/coercion/issue-73886.stderr index 0d4c90017cf..a287aa29e11 100644 --- a/tests/ui/coercion/issue-73886.stderr +++ b/tests/ui/coercion/issue-73886.stderr @@ -3,6 +3,8 @@ error[E0605]: non-primitive cast: `&&[i32; 1]` as `&[_]` | LL | let _ = &&[0] as &[_]; | ^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object + | + = note: casting reference expression `&&[0]` because `&` binds tighter than `as` error[E0605]: non-primitive cast: `u32` as `Option<_>` --> $DIR/issue-73886.rs:4:13 |