diff --git a/compiler/rustc_hir_typeck/src/method/mod.rs b/compiler/rustc_hir_typeck/src/method/mod.rs index b9b27e8627af..f3c43e3f4973 100644 --- a/compiler/rustc_hir_typeck/src/method/mod.rs +++ b/compiler/rustc_hir_typeck/src/method/mod.rs @@ -57,7 +57,7 @@ pub enum MethodError<'tcx> { PrivateMatch(DefKind, DefId, Vec), // Found a `Self: Sized` bound where `Self` is a trait object. - IllegalSizedBound(Vec, bool, Span), + IllegalSizedBound(Vec, bool, Span, &'tcx hir::Expr<'tcx>), // Found a match, but the return type is wrong BadReturnType, @@ -236,7 +236,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { _ => Vec::new(), }; - return Err(IllegalSizedBound(candidates, needs_mut, span)); + return Err(IllegalSizedBound(candidates, needs_mut, span, self_expr)); } Ok(result.callee) diff --git a/compiler/rustc_hir_typeck/src/method/suggest.rs b/compiler/rustc_hir_typeck/src/method/suggest.rs index 1a42f9d07b18..5a43db69fd49 100644 --- a/compiler/rustc_hir_typeck/src/method/suggest.rs +++ b/compiler/rustc_hir_typeck/src/method/suggest.rs @@ -176,7 +176,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { err.emit(); } - MethodError::IllegalSizedBound(candidates, needs_mut, bound_span) => { + MethodError::IllegalSizedBound(candidates, needs_mut, bound_span, self_expr) => { let msg = format!("the `{}` method cannot be invoked on a trait object", item_name); let mut err = self.sess().struct_span_err(span, &msg); err.span_label(bound_span, "this has a `Sized` requirement"); @@ -197,7 +197,34 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { *region, ty::TypeAndMut { ty: *t_type, mutbl: mutability.invert() }, ); - err.note(&format!("you need `{}` instead of `{}`", trait_type, rcvr_ty)); + let msg = format!("you need `{}` instead of `{}`", trait_type, rcvr_ty); + let mut kind = &self_expr.kind; + while let hir::ExprKind::AddrOf(_, _, expr) + | hir::ExprKind::Unary(hir::UnOp::Deref, expr) = kind + { + kind = &expr.kind; + } + if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = kind + && let hir::def::Res::Local(hir_id) = path.res + && let Some(hir::Node::Pat(binding)) = self.tcx.hir().find(hir_id) + && let parent_hir_id = self.tcx.hir().get_parent_node(binding.hir_id) + && let Some(hir::Node::Param(param)) = self.tcx.hir().find(parent_hir_id) + && let parent_hir_id = self.tcx.hir().get_parent_node(param.hir_id) + && let Some(node) = self.tcx.hir().find(parent_hir_id) + && let Some(decl) = node.fn_decl() + && let Some(ty) = decl.inputs.iter().find(|ty| ty.span == param.ty_span) + && let hir::TyKind::Ref(_, mut_ty) = &ty.kind + && let hir::Mutability::Not = mut_ty.mutbl + { + err.span_suggestion_verbose( + mut_ty.ty.span.shrink_to_lo(), + &msg, + "mut ", + Applicability::MachineApplicable, + ); + } else { + err.help(&msg); + } } } err.emit(); diff --git a/src/test/ui/illegal-sized-bound/mutability-mismatch-arg.fixed b/src/test/ui/illegal-sized-bound/mutability-mismatch-arg.fixed new file mode 100644 index 000000000000..260ef5458d4b --- /dev/null +++ b/src/test/ui/illegal-sized-bound/mutability-mismatch-arg.fixed @@ -0,0 +1,9 @@ +// run-rustfix +fn test(t: &mut dyn Iterator) -> u64 { + *t.min().unwrap() //~ ERROR the `min` method cannot be invoked on a trait object +} + +fn main() { + let array = [0u64]; + test(&mut array.iter()); +} diff --git a/src/test/ui/illegal-sized-bound/mutability-mismatch-arg.rs b/src/test/ui/illegal-sized-bound/mutability-mismatch-arg.rs new file mode 100644 index 000000000000..7a1656507f2c --- /dev/null +++ b/src/test/ui/illegal-sized-bound/mutability-mismatch-arg.rs @@ -0,0 +1,9 @@ +// run-rustfix +fn test(t: &dyn Iterator) -> u64 { + *t.min().unwrap() //~ ERROR the `min` method cannot be invoked on a trait object +} + +fn main() { + let array = [0u64]; + test(&mut array.iter()); +} diff --git a/src/test/ui/illegal-sized-bound/mutability-mismatch-arg.stderr b/src/test/ui/illegal-sized-bound/mutability-mismatch-arg.stderr new file mode 100644 index 000000000000..9b4b9b65d104 --- /dev/null +++ b/src/test/ui/illegal-sized-bound/mutability-mismatch-arg.stderr @@ -0,0 +1,16 @@ +error: the `min` method cannot be invoked on a trait object + --> $DIR/mutability-mismatch-arg.rs:3:9 + | +LL | *t.min().unwrap() + | ^^^ + --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL + | + = note: this has a `Sized` requirement + | +help: you need `&mut dyn Iterator` instead of `&dyn Iterator` + | +LL | fn test(t: &mut dyn Iterator) -> u64 { + | +++ + +error: aborting due to previous error + diff --git a/src/test/ui/illegal-sized-bound/mutability-mismatch.rs b/src/test/ui/illegal-sized-bound/mutability-mismatch.rs index deb84f6fe97c..aa9b3d038914 100644 --- a/src/test/ui/illegal-sized-bound/mutability-mismatch.rs +++ b/src/test/ui/illegal-sized-bound/mutability-mismatch.rs @@ -27,8 +27,8 @@ impl Trait for Type { fn main() { (&MutType as &dyn MutTrait).function(); //~^ ERROR the `function` method cannot be invoked on a trait object - //~| NOTE you need `&mut dyn MutTrait` instead of `&dyn MutTrait` + //~| HELP you need `&mut dyn MutTrait` instead of `&dyn MutTrait` (&mut Type as &mut dyn Trait).function(); //~^ ERROR the `function` method cannot be invoked on a trait object - //~| NOTE you need `&dyn Trait` instead of `&mut dyn Trait` + //~| HELP you need `&dyn Trait` instead of `&mut dyn Trait` } diff --git a/src/test/ui/illegal-sized-bound/mutability-mismatch.stderr b/src/test/ui/illegal-sized-bound/mutability-mismatch.stderr index dbbf79a4f1a0..0120b9f91e94 100644 --- a/src/test/ui/illegal-sized-bound/mutability-mismatch.stderr +++ b/src/test/ui/illegal-sized-bound/mutability-mismatch.stderr @@ -7,7 +7,7 @@ LL | Self: Sized; LL | (&MutType as &dyn MutTrait).function(); | ^^^^^^^^ | - = note: you need `&mut dyn MutTrait` instead of `&dyn MutTrait` + = help: you need `&mut dyn MutTrait` instead of `&dyn MutTrait` error: the `function` method cannot be invoked on a trait object --> $DIR/mutability-mismatch.rs:31:35 @@ -18,7 +18,7 @@ LL | Self: Sized; LL | (&mut Type as &mut dyn Trait).function(); | ^^^^^^^^ | - = note: you need `&dyn Trait` instead of `&mut dyn Trait` + = help: you need `&dyn Trait` instead of `&mut dyn Trait` error: aborting due to 2 previous errors diff --git a/src/test/ui/suggestions/imm-ref-trait-object.stderr b/src/test/ui/suggestions/imm-ref-trait-object.stderr index 7791b308d5d0..02847ed8c4c6 100644 --- a/src/test/ui/suggestions/imm-ref-trait-object.stderr +++ b/src/test/ui/suggestions/imm-ref-trait-object.stderr @@ -7,7 +7,10 @@ LL | t.min().unwrap() | = note: this has a `Sized` requirement | - = note: you need `&mut dyn Iterator` instead of `&dyn Iterator` +help: you need `&mut dyn Iterator` instead of `&dyn Iterator` + | +LL | fn test(t: &mut dyn Iterator) -> u64 { + | +++ error: aborting due to previous error