diff options
6 files changed, 114 insertions, 57 deletions
diff --git a/compiler/rustc_hir_typeck/src/demand.rs b/compiler/rustc_hir_typeck/src/demand.rs index 367e7c6de95..bc076670585 100644 --- a/compiler/rustc_hir_typeck/src/demand.rs +++ b/compiler/rustc_hir_typeck/src/demand.rs @@ -851,32 +851,32 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { && let hir::PatKind::Binding(hir::BindingMode::MUT, _hir_id, ident, _) = pat.kind // Look for the type corresponding to the argument pattern we have in the argument list. - && let Some(ty_sugg) = fn_decl + && let Some(ty_ref) = fn_decl .inputs .iter() - .filter_map(|ty| { - if ty.span == *ty_span - && let hir::TyKind::Ref(lt, x) = ty.kind - { - // `&'name Ty` -> `&'name mut Ty` or `&Ty` -> `&mut Ty` - Some(( - x.ty.span.shrink_to_lo(), - format!( - "{}mut ", - if lt.ident.span.lo() == lt.ident.span.hi() { "" } else { " " } - ), - )) - } else { - None - } + .filter_map(|ty| match ty.kind { + hir::TyKind::Ref(lt, mut_ty) if ty.span == *ty_span => Some((lt, mut_ty)), + _ => None, }) .next() { - let sugg = vec![ - ty_sugg, + let mut sugg = if ty_ref.1.mutbl.is_mut() { + // Leave `&'name mut Ty` and `&mut Ty` as they are (#136028). + vec![] + } else { + // `&'name Ty` -> `&'name mut Ty` or `&Ty` -> `&mut Ty` + vec![( + ty_ref.1.ty.span.shrink_to_lo(), + format!( + "{}mut ", + if ty_ref.0.ident.span.lo() == ty_ref.0.ident.span.hi() { "" } else { " " }, + ), + )] + }; + sugg.extend([ (pat.span.until(ident.span), String::new()), (lhs.span.shrink_to_lo(), "*".to_string()), - ]; + ]); // We suggest changing the argument from `mut ident: &Ty` to `ident: &'_ mut Ty` and the // assignment from `ident = val;` to `*ident = val;`. err.multipart_suggestion_verbose( diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs index 196a0a46962..0aa50ad19ff 100644 --- a/compiler/rustc_passes/src/errors.rs +++ b/compiler/rustc_passes/src/errors.rs @@ -1791,7 +1791,7 @@ pub(crate) struct UnusedAssign { pub(crate) struct UnusedAssignSuggestion { pub pre: &'static str, #[suggestion_part(code = "{pre}mut ")] - pub ty_span: Span, + pub ty_span: Option<Span>, #[suggestion_part(code = "")] pub ty_ref_span: Span, #[suggestion_part(code = "*")] diff --git a/compiler/rustc_passes/src/liveness.rs b/compiler/rustc_passes/src/liveness.rs index 426899a4d5c..73da8855e10 100644 --- a/compiler/rustc_passes/src/liveness.rs +++ b/compiler/rustc_passes/src/liveness.rs @@ -1620,24 +1620,28 @@ impl<'tcx> Liveness<'_, 'tcx> { && let item = self.ir.tcx.hir_owner_node(item_id) && let Some(fn_decl) = item.fn_decl() && let hir::PatKind::Binding(hir::BindingMode::MUT, _hir_id, ident, _) = pat.kind - && let Some((ty_span, pre)) = fn_decl + && let Some((lt, mut_ty)) = fn_decl .inputs .iter() .filter_map(|ty| { if ty.span == *ty_span && let hir::TyKind::Ref(lt, mut_ty) = ty.kind { - // `&'name Ty` -> `&'name mut Ty` or `&Ty` -> `&mut Ty` - Some(( - mut_ty.ty.span.shrink_to_lo(), - if lt.ident.span.lo() == lt.ident.span.hi() { "" } else { " " }, - )) + Some((lt, mut_ty)) } else { None } }) .next() { + let ty_span = if mut_ty.mutbl.is_mut() { + // Leave `&'name mut Ty` and `&mut Ty` as they are (#136028). + None + } else { + // `&'name Ty` -> `&'name mut Ty` or `&Ty` -> `&mut Ty` + Some(mut_ty.ty.span.shrink_to_lo()) + }; + let pre = if lt.ident.span.lo() == lt.ident.span.hi() { "" } else { " " }; Some(errors::UnusedAssignSuggestion { ty_span, pre, diff --git a/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.fixed b/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.fixed index 914ca1f3a06..b58c3a6720d 100644 --- a/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.fixed +++ b/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.fixed @@ -1,17 +1,26 @@ //@ run-rustfix #![deny(unused_assignments, unused_variables)] +#![allow(unused_mut)] struct Object; fn change_object(object: &mut Object) { //~ HELP you might have meant to mutate - let object2 = Object; - *object = object2; //~ ERROR mismatched types + let object2 = Object; + *object = object2; //~ ERROR mismatched types } fn change_object2(object: &mut Object) { //~ ERROR variable `object` is assigned to, but never used + //~^ HELP you might have meant to mutate + let object2 = Object; + *object = object2; + //~^ ERROR `object2` does not live long enough + //~| ERROR value assigned to `object` is never read +} + +fn change_object3(object: &mut Object) { //~ ERROR variable `object` is assigned to, but never used //~^ HELP you might have meant to mutate - let object2 = Object; + let mut object2 = Object; //~ HELP consider changing this to be mutable *object = object2; - //~^ ERROR `object2` does not live long enough + //~^ ERROR cannot borrow `object2` as mutable //~| ERROR value assigned to `object` is never read } @@ -19,4 +28,5 @@ fn main() { let mut object = Object; change_object(&mut object); change_object2(&mut object); + change_object3(&mut object); } diff --git a/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs b/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs index 331359a98d1..1fd222e0db1 100644 --- a/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs +++ b/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs @@ -1,17 +1,26 @@ //@ run-rustfix #![deny(unused_assignments, unused_variables)] +#![allow(unused_mut)] struct Object; fn change_object(mut object: &Object) { //~ HELP you might have meant to mutate - let object2 = Object; - object = object2; //~ ERROR mismatched types + let object2 = Object; + object = object2; //~ ERROR mismatched types } fn change_object2(mut object: &Object) { //~ ERROR variable `object` is assigned to, but never used + //~^ HELP you might have meant to mutate + let object2 = Object; + object = &object2; + //~^ ERROR `object2` does not live long enough + //~| ERROR value assigned to `object` is never read +} + +fn change_object3(mut object: &mut Object) { //~ ERROR variable `object` is assigned to, but never used //~^ HELP you might have meant to mutate - let object2 = Object; - object = &object2; - //~^ ERROR `object2` does not live long enough + let object2 = Object; //~ HELP consider changing this to be mutable + object = &mut object2; + //~^ ERROR cannot borrow `object2` as mutable //~| ERROR value assigned to `object` is never read } @@ -19,4 +28,5 @@ fn main() { let mut object = Object; change_object(&mut object); change_object2(&mut object); + change_object3(&mut object); } diff --git a/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.stderr b/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.stderr index e7e4003936a..0330853d922 100644 --- a/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.stderr +++ b/tests/ui/fn/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.stderr @@ -1,24 +1,24 @@ error[E0308]: mismatched types - --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:7:14 + --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:8:13 | LL | fn change_object(mut object: &Object) { | ------- expected due to this parameter type -LL | let object2 = Object; -LL | object = object2; - | ^^^^^^^ expected `&Object`, found `Object` +LL | let object2 = Object; +LL | object = object2; + | ^^^^^^^ expected `&Object`, found `Object` | help: you might have meant to mutate the pointed at value being passed in, instead of changing the reference in the local binding | LL ~ fn change_object(object: &mut Object) { -LL | let object2 = Object; -LL ~ *object = object2; +LL | let object2 = Object; +LL ~ *object = object2; | error: value assigned to `object` is never read - --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:13:5 + --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:14:4 | -LL | object = &object2; - | ^^^^^^ +LL | object = &object2; + | ^^^^^^ | note: the lint level is defined here --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:2:9 @@ -29,12 +29,12 @@ help: you might have meant to mutate the pointed at value being passed in, inste | LL ~ fn change_object2(object: &mut Object) { LL | -LL | let object2 = Object; -LL ~ *object = object2; +LL | let object2 = Object; +LL ~ *object = object2; | error: variable `object` is assigned to, but never used - --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:10:23 + --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:11:23 | LL | fn change_object2(mut object: &Object) { | ^^^^^^ @@ -47,23 +47,56 @@ LL | #![deny(unused_assignments, unused_variables)] | ^^^^^^^^^^^^^^^^ error[E0597]: `object2` does not live long enough - --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:13:14 + --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:14:13 | LL | fn change_object2(mut object: &Object) { | - let's call the lifetime of this reference `'1` LL | -LL | let object2 = Object; - | ------- binding `object2` declared here -LL | object = &object2; - | ---------^^^^^^^^ - | | | - | | borrowed value does not live long enough - | assignment requires that `object2` is borrowed for `'1` +LL | let object2 = Object; + | ------- binding `object2` declared here +LL | object = &object2; + | ---------^^^^^^^^ + | | | + | | borrowed value does not live long enough + | assignment requires that `object2` is borrowed for `'1` ... LL | } | - `object2` dropped here while still borrowed -error: aborting due to 4 previous errors +error: value assigned to `object` is never read + --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:22:5 + | +LL | object = &mut object2; + | ^^^^^^ + | +help: you might have meant to mutate the pointed at value being passed in, instead of changing the reference in the local binding + | +LL ~ fn change_object3(object: &mut Object) { +LL | +LL | let object2 = Object; +LL ~ *object = object2; + | + +error: variable `object` is assigned to, but never used + --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:19:23 + | +LL | fn change_object3(mut object: &mut Object) { + | ^^^^^^ + | + = note: consider using `_object` instead + +error[E0596]: cannot borrow `object2` as mutable, as it is not declared as mutable + --> $DIR/mut-arg-of-borrowed-type-meant-to-be-arg-of-mut-borrow.rs:22:14 + | +LL | object = &mut object2; + | ^^^^^^^^^^^^ cannot borrow as mutable + | +help: consider changing this to be mutable + | +LL | let mut object2 = Object; + | +++ + +error: aborting due to 7 previous errors -Some errors have detailed explanations: E0308, E0597. +Some errors have detailed explanations: E0308, E0596, E0597. For more information about an error, try `rustc --explain E0308`. |