diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs index d2897f1c011..6cd74961cc7 100644 --- a/compiler/rustc_hir_typeck/src/pat.rs +++ b/compiler/rustc_hir_typeck/src/pat.rs @@ -335,9 +335,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { match adjust_mode { AdjustMode::Pass => (expected, def_br, max_ref_mutbl), AdjustMode::Reset => (expected, ByRef::No, MutblCap::Mut), - AdjustMode::Peel => { - self.peel_off_references(pat, expected, def_br, Mutability::Mut, max_ref_mutbl) - } + AdjustMode::Peel => self.peel_off_references(pat, expected, def_br, max_ref_mutbl), } } @@ -408,7 +406,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { pat: &'tcx Pat<'tcx>, expected: Ty<'tcx>, mut def_br: ByRef, - max_peelable_mutability: Mutability, mut max_ref_mutability: MutblCap, ) -> (Ty<'tcx>, ByRef, MutblCap) { let mut expected = self.try_structurally_resolve_type(pat.span, expected); @@ -421,9 +418,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { // // See the examples in `ui/match-defbm*.rs`. let mut pat_adjustments = vec![]; - while let ty::Ref(_, inner_ty, inner_mutability) = *expected.kind() - && inner_mutability <= max_peelable_mutability - { + while let ty::Ref(_, inner_ty, inner_mutability) = *expected.kind() { debug!("inspecting {:?}", expected); debug!("current discriminant is Ref, inserting implicit deref"); @@ -2129,32 +2124,39 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { pat.span.at_least_rust_2024() && self.tcx.features().ref_pat_eat_one_layer_2024; if new_match_ergonomics { + let pat_prefix_span = + inner.span.find_ancestor_inside(pat.span).map(|end| pat.span.until(end)); + if pat_mutbl == Mutability::Not { // Prevent the inner pattern from binding with `ref mut`. - pat_info.max_ref_mutbl = pat_info.max_ref_mutbl.cap_to_weakly_not( - inner.span.find_ancestor_inside(pat.span).map(|end| pat.span.until(end)), - ); + pat_info.max_ref_mutbl = pat_info.max_ref_mutbl.cap_to_weakly_not(pat_prefix_span); } - if let ByRef::Yes(inh_mut) = pat_info.binding_mode - && pat_mutbl <= inh_mut - { + if let ByRef::Yes(inh_mut) = pat_info.binding_mode { + // ref pattern consumes inherited reference + + if pat_mutbl > inh_mut { + // Tried to match inherited `ref` with `&mut`, which is an error + let err_msg = "cannot match inherited `&` with `&mut` pattern"; + let err = if let Some(span) = pat_prefix_span { + let mut err = self.dcx().struct_span_err(span, err_msg); + err.span_suggestion_verbose( + span, + "replace this `&mut` pattern with `&`", + "&", + Applicability::MachineApplicable, + ); + err + } else { + self.dcx().struct_span_err(pat.span, err_msg) + }; + err.emit(); + } + pat_info.binding_mode = ByRef::No; self.typeck_results.borrow_mut().skipped_ref_pats_mut().insert(pat.hir_id); self.check_pat(inner, expected, pat_info); return expected; - } else if pat_mutbl == Mutability::Mut { - // `&mut` patterns pell off `&` references - let (new_expected, new_bm, max_ref_mutbl) = self.peel_off_references( - pat, - expected, - pat_info.binding_mode, - Mutability::Not, - pat_info.max_ref_mutbl, - ); - expected = new_expected; - pat_info.binding_mode = new_bm; - pat_info.max_ref_mutbl = max_ref_mutbl; } } else { // Reset binding mode on old editions diff --git a/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024.rs b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024.rs index 62e4f82a3ff..829b7f86e26 100644 --- a/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024.rs +++ b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024.rs @@ -23,9 +23,6 @@ pub fn main() { if let Some(Some(&x)) = &Some(&Some(0)) { let _: u32 = x; } - if let Some(&mut Some(&x)) = &Some(&mut Some(0)) { - let _: u32 = x; - } if let Some(&Some(&x)) = &mut Some(&Some(0)) { let _: u32 = x; } @@ -35,9 +32,6 @@ pub fn main() { if let Some(&Some(&mut ref x)) = Some(&Some(&mut 0)) { let _: &u32 = x; } - if let Some(Some(&mut x)) = &Some(Some(&mut 0)) { - let _: &u32 = x; - } if let &Some(Some(x)) = &Some(&mut Some(0)) { let _: &u32 = x; } @@ -59,13 +53,4 @@ pub fn main() { if let Some(&Some(x)) = &mut Some(Some(0)) { let _: u32 = x; } - - let &mut x = &&mut 0; - let _: &u32 = x; - - let &mut x = &&&&&&&&&&&&&&&&&&&&&&&&&&&&mut 0; - let _: &u32 = x; - - let &mut &mut &mut &mut x = &mut &&&&mut &&&mut &mut 0; - let _: &u32 = x; } diff --git a/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024_fail.rs b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024_fail.rs index 96b4ff77ddb..a2a0c73b53b 100644 --- a/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024_fail.rs +++ b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024_fail.rs @@ -5,26 +5,26 @@ pub fn main() { if let Some(&mut Some(&_)) = &Some(&Some(0)) { - //~^ ERROR: mismatched types + //~^ ERROR: cannot match inherited `&` with `&mut` pattern } if let Some(&Some(&mut _)) = &Some(&mut Some(0)) { - //~^ ERROR: mismatched types + //~^ ERROR: cannot match inherited `&` with `&mut` pattern } if let Some(&Some(x)) = &mut Some(&Some(0)) { let _: &mut u32 = x; //~^ ERROR: mismatched types } if let Some(&Some(&mut _)) = &mut Some(&Some(0)) { - //~^ ERROR: mismatched types + //~^ ERROR: cannot match inherited `&` with `&mut` pattern } if let Some(&Some(Some((&mut _)))) = &Some(Some(&mut Some(0))) { - //~^ ERROR: mismatched types + //~^ ERROR: cannot match inherited `&` with `&mut` pattern } if let Some(&mut Some(x)) = &Some(Some(0)) { - //~^ ERROR: mismatched types + //~^ ERROR: cannot match inherited `&` with `&mut` pattern } if let Some(&mut Some(x)) = &Some(Some(0)) { - //~^ ERROR: mismatched types + //~^ ERROR: cannot match inherited `&` with `&mut` pattern } let &mut _ = &&0; @@ -32,4 +32,21 @@ pub fn main() { let &mut _ = &&&&&&&&&&&&&&&&&&&&&&&&&&&&0; //~^ ERROR: mismatched types + + if let Some(&mut Some(&_)) = &Some(&mut Some(0)) { + //~^ ERROR: cannot match inherited `&` with `&mut` pattern + } + + if let Some(Some(&mut x)) = &Some(Some(&mut 0)) { + //~^ ERROR: cannot match inherited `&` with `&mut` pattern + } + + let &mut _ = &&mut 0; + //~^ ERROR: mismatched types + + let &mut _ = &&&&&&&&&&&&&&&&&&&&&&&&&&&&mut 0; + //~^ ERROR: mismatched types + + let &mut &mut &mut &mut _ = &mut &&&&mut &&&mut &mut 0; + //~^ ERROR: mismatched types } diff --git a/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024_fail.stderr b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024_fail.stderr index e06a645fc0d..cad67b4f8d6 100644 --- a/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024_fail.stderr +++ b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024_fail.stderr @@ -1,24 +1,24 @@ -error[E0308]: mismatched types +error: cannot match inherited `&` with `&mut` pattern --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:7:17 | LL | if let Some(&mut Some(&_)) = &Some(&Some(0)) { - | ^^^^^^^^^^^^^ --------------- this expression has type `&Option<&Option<{integer}>>` - | | - | expected `Option<{integer}>`, found `&mut _` + | ^^^^^ | - = note: expected enum `Option<{integer}>` - found mutable reference `&mut _` +help: replace this `&mut` pattern with `&` + | +LL | if let Some(&Some(&_)) = &Some(&Some(0)) { + | ~ -error[E0308]: mismatched types +error: cannot match inherited `&` with `&mut` pattern --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:10:23 | LL | if let Some(&Some(&mut _)) = &Some(&mut Some(0)) { - | ^^^^^^ ------------------- this expression has type `&Option<&mut Option<{integer}>>` - | | - | expected integer, found `&mut _` + | ^^^^^ | - = note: expected type `{integer}` - found mutable reference `&mut _` +help: replace this `&mut` pattern with `&` + | +LL | if let Some(&Some(&_)) = &Some(&mut Some(0)) { + | ~ error[E0308]: mismatched types --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:14:27 @@ -31,49 +31,49 @@ LL | let _: &mut u32 = x; = note: expected mutable reference `&mut u32` found reference `&{integer}` -error[E0308]: mismatched types +error: cannot match inherited `&` with `&mut` pattern --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:17:23 | LL | if let Some(&Some(&mut _)) = &mut Some(&Some(0)) { - | ^^^^^^ ------------------- this expression has type `&mut Option<&Option<{integer}>>` - | | - | expected integer, found `&mut _` + | ^^^^^ | - = note: expected type `{integer}` - found mutable reference `&mut _` +help: replace this `&mut` pattern with `&` + | +LL | if let Some(&Some(&_)) = &mut Some(&Some(0)) { + | ~ -error[E0308]: mismatched types +error: cannot match inherited `&` with `&mut` pattern --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:20:29 | LL | if let Some(&Some(Some((&mut _)))) = &Some(Some(&mut Some(0))) { - | ^^^^^^ ------------------------- this expression has type `&Option>>` - | | - | expected integer, found `&mut _` + | ^^^^^ | - = note: expected type `{integer}` - found mutable reference `&mut _` +help: replace this `&mut` pattern with `&` + | +LL | if let Some(&Some(Some((&_)))) = &Some(Some(&mut Some(0))) { + | ~ -error[E0308]: mismatched types +error: cannot match inherited `&` with `&mut` pattern --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:23:17 | LL | if let Some(&mut Some(x)) = &Some(Some(0)) { - | ^^^^^^^^^^^^ -------------- this expression has type `&Option>` - | | - | expected `Option<{integer}>`, found `&mut _` + | ^^^^^ | - = note: expected enum `Option<{integer}>` - found mutable reference `&mut _` +help: replace this `&mut` pattern with `&` + | +LL | if let Some(&Some(x)) = &Some(Some(0)) { + | ~ -error[E0308]: mismatched types +error: cannot match inherited `&` with `&mut` pattern --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:26:17 | LL | if let Some(&mut Some(x)) = &Some(Some(0)) { - | ^^^^^^^^^^^^ -------------- this expression has type `&Option>` - | | - | expected `Option<{integer}>`, found `&mut _` + | ^^^^^ | - = note: expected enum `Option<{integer}>` - found mutable reference `&mut _` +help: replace this `&mut` pattern with `&` + | +LL | if let Some(&Some(x)) = &Some(Some(0)) { + | ~ error[E0308]: mismatched types --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:30:9 @@ -81,9 +81,9 @@ error[E0308]: mismatched types LL | let &mut _ = &&0; | ^^^^^^ --- this expression has type `&&{integer}` | | - | expected integer, found `&mut _` + | types differ in mutability | - = note: expected type `{integer}` + = note: expected reference `&&{integer}` found mutable reference `&mut _` error[E0308]: mismatched types @@ -92,11 +92,66 @@ error[E0308]: mismatched types LL | let &mut _ = &&&&&&&&&&&&&&&&&&&&&&&&&&&&0; | ^^^^^^ ----------------------------- this expression has type `&&&&&&&&&&&&&&&&&&&&&&&&&&&&{integer}` | | - | expected integer, found `&mut _` + | types differ in mutability | - = note: expected type `{integer}` + = note: expected reference `&&&&&&&&&&&&&&&&&&&&&&&&&&&&{integer}` found mutable reference `&mut _` -error: aborting due to 9 previous errors +error: cannot match inherited `&` with `&mut` pattern + --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:36:17 + | +LL | if let Some(&mut Some(&_)) = &Some(&mut Some(0)) { + | ^^^^^ + | +help: replace this `&mut` pattern with `&` + | +LL | if let Some(&Some(&_)) = &Some(&mut Some(0)) { + | ~ + +error: cannot match inherited `&` with `&mut` pattern + --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:40:22 + | +LL | if let Some(Some(&mut x)) = &Some(Some(&mut 0)) { + | ^^^^^ + | +help: replace this `&mut` pattern with `&` + | +LL | if let Some(Some(&x)) = &Some(Some(&mut 0)) { + | ~ + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:44:9 + | +LL | let &mut _ = &&mut 0; + | ^^^^^^ ------- this expression has type `&&mut {integer}` + | | + | types differ in mutability + | + = note: expected reference `&&mut {integer}` + found mutable reference `&mut _` + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:47:9 + | +LL | let &mut _ = &&&&&&&&&&&&&&&&&&&&&&&&&&&&mut 0; + | ^^^^^^ --------------------------------- this expression has type `&&&&&&&&&&&&&&&&&&&&&&&&&&&&mut {integer}` + | | + | types differ in mutability + | + = note: expected reference `&&&&&&&&&&&&&&&&&&&&&&&&&&&&mut {integer}` + found mutable reference `&mut _` + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:50:14 + | +LL | let &mut &mut &mut &mut _ = &mut &&&&mut &&&mut &mut 0; + | ^^^^^^^^^^^^^^^^ -------------------------- this expression has type `&mut &&&&mut &&&mut &mut {integer}` + | | + | types differ in mutability + | + = note: expected reference `&&&&mut &&&mut &mut {integer}` + found mutable reference `&mut _` + +error: aborting due to 14 previous errors For more information about this error, try `rustc --explain E0308`.