diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs index e6b19817de3..5d17675a532 100644 --- a/compiler/rustc_feature/src/unstable.rs +++ b/compiler/rustc_feature/src/unstable.rs @@ -571,6 +571,8 @@ declare_features! ( (unstable, proc_macro_hygiene, "1.30.0", Some(54727)), /// Allows `&raw const $place_expr` and `&raw mut $place_expr` expressions. (unstable, raw_ref_op, "1.41.0", Some(64490)), + /// Makes `&` and `&mut` patterns eat only one layer of references in Rust 2024. + (incomplete, ref_pat_eat_one_layer_2024, "CURRENT_RUSTC_VERSION", Some(123076)), /// Allows `&` and `&mut` patterns to consume match-ergonomics-inserted references. (incomplete, ref_pat_everywhere, "CURRENT_RUSTC_VERSION", Some(123076)), /// Allows using the `#[register_tool]` attribute. diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs index db4bd132b7e..ff7716ce7ea 100644 --- a/compiler/rustc_hir_typeck/src/pat.rs +++ b/compiler/rustc_hir_typeck/src/pat.rs @@ -294,7 +294,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { AdjustMode::Pass => (expected, def_bm, false), AdjustMode::Reset => (expected, INITIAL_BM, false), AdjustMode::ResetAndConsumeRef(mutbl) => { - (expected, INITIAL_BM, def_bm.0 == ByRef::Yes(mutbl)) + let mutbls_match = def_bm.0 == ByRef::Yes(mutbl); + if pat.span.at_least_rust_2024() && self.tcx.features().ref_pat_eat_one_layer_2024 { + if mutbls_match { + (expected, INITIAL_BM, true) + } else { + (expected, def_bm, false) + } + } else { + (expected, INITIAL_BM, mutbls_match) + } } AdjustMode::Peel => { let peeled = self.peel_off_references(pat, expected, def_bm); @@ -2056,61 +2065,70 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { pat_info: PatInfo<'tcx, '_>, consumed_inherited_ref: bool, ) -> Ty<'tcx> { - let tcx = self.tcx; - let expected = self.shallow_resolve(expected); - let (ref_ty, inner_ty) = match self.check_dereferenceable(pat.span, expected, inner) { - Ok(()) => { - // `demand::subtype` would be good enough, but using `eqtype` turns - // out to be equally general. See (note_1) for details. + if consumed_inherited_ref + && pat.span.at_least_rust_2024() + && self.tcx.features().ref_pat_eat_one_layer_2024 + { + self.typeck_results.borrow_mut().skipped_ref_pats_mut().insert(pat.hir_id); + self.check_pat(inner, expected, pat_info); + expected + } else { + let tcx = self.tcx; + let expected = self.shallow_resolve(expected); + let (ref_ty, inner_ty) = match self.check_dereferenceable(pat.span, expected, inner) { + Ok(()) => { + // `demand::subtype` would be good enough, but using `eqtype` turns + // out to be equally general. See (note_1) for details. - // Take region, inner-type from expected type if we can, - // to avoid creating needless variables. This also helps with - // the bad interactions of the given hack detailed in (note_1). - debug!("check_pat_ref: expected={:?}", expected); - match *expected.kind() { - ty::Ref(_, r_ty, r_mutbl) if r_mutbl == mutbl => (expected, r_ty), - _ => { - if consumed_inherited_ref && self.tcx.features().ref_pat_everywhere { - // We already matched against a match-ergonmics inserted reference, - // so we don't need to match against a reference from the original type. - // Save this infor for use in lowering later - self.typeck_results - .borrow_mut() - .skipped_ref_pats_mut() - .insert(pat.hir_id); - (expected, expected) - } else { - let inner_ty = self.next_ty_var(TypeVariableOrigin { - param_def_id: None, - span: inner.span, - }); - let ref_ty = self.new_ref_ty(pat.span, mutbl, inner_ty); - debug!("check_pat_ref: demanding {:?} = {:?}", expected, ref_ty); - let err = self.demand_eqtype_pat_diag( - pat.span, - expected, - ref_ty, - pat_info.top_info, - ); + // Take region, inner-type from expected type if we can, + // to avoid creating needless variables. This also helps with + // the bad interactions of the given hack detailed in (note_1). + debug!("check_pat_ref: expected={:?}", expected); + match *expected.kind() { + ty::Ref(_, r_ty, r_mutbl) if r_mutbl == mutbl => (expected, r_ty), + _ => { + if consumed_inherited_ref && self.tcx.features().ref_pat_everywhere { + // We already matched against a match-ergonmics inserted reference, + // so we don't need to match against a reference from the original type. + // Save this infor for use in lowering later + self.typeck_results + .borrow_mut() + .skipped_ref_pats_mut() + .insert(pat.hir_id); + (expected, expected) + } else { + let inner_ty = self.next_ty_var(TypeVariableOrigin { + param_def_id: None, + span: inner.span, + }); + let ref_ty = self.new_ref_ty(pat.span, mutbl, inner_ty); + debug!("check_pat_ref: demanding {:?} = {:?}", expected, ref_ty); + let err = self.demand_eqtype_pat_diag( + pat.span, + expected, + ref_ty, + pat_info.top_info, + ); - // Look for a case like `fn foo(&foo: u32)` and suggest - // `fn foo(foo: &u32)` - if let Some(mut err) = err { - self.borrow_pat_suggestion(&mut err, pat); - err.emit(); + // Look for a case like `fn foo(&foo: u32)` and suggest + // `fn foo(foo: &u32)` + if let Some(mut err) = err { + self.borrow_pat_suggestion(&mut err, pat); + err.emit(); + } + (ref_ty, inner_ty) } - (ref_ty, inner_ty) } } } - } - Err(guar) => { - let err = Ty::new_error(tcx, guar); - (err, err) - } - }; - self.check_pat(inner, inner_ty, pat_info); - ref_ty + Err(guar) => { + let err = Ty::new_error(tcx, guar); + (err, err) + } + }; + self.check_pat(inner, inner_ty, pat_info); + ref_ty + } } /// Create a reference type with a fresh region variable. diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index bfd0f77c237..baf7fab3ad8 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -1460,6 +1460,7 @@ symbols! { receiver, recursion_limit, reexport_test_harness_main, + ref_pat_eat_one_layer_2024, ref_pat_everywhere, ref_unwind_safe_trait, reference, diff --git a/tests/ui/match/ref_pat_eat_one_layer_2024/feature-gate-ref_pat_eat_one_layer_2024.rs b/tests/ui/match/ref_pat_eat_one_layer_2024/feature-gate-ref_pat_eat_one_layer_2024.rs new file mode 100644 index 00000000000..83f1ee6a77e --- /dev/null +++ b/tests/ui/match/ref_pat_eat_one_layer_2024/feature-gate-ref_pat_eat_one_layer_2024.rs @@ -0,0 +1,37 @@ +//@ edition: 2024 +//@ compile-flags: -Zunstable-options + +pub fn main() { + if let Some(Some(&x)) = &Some(&Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(Some(&x)) = &Some(Some(&0)) { + let _: &u32 = x; + //~^ ERROR: mismatched types + } + if let Some(Some(&&x)) = &Some(Some(&0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(&Some(x)) = &Some(Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(Some(&mut x)) = &mut Some(&mut Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(Some(&x)) = &Some(&Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(&mut Some(&x)) = &Some(&mut Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(&Some(&mut x)) = &mut Some(&Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } +} diff --git a/tests/ui/match/ref_pat_eat_one_layer_2024/feature-gate-ref_pat_eat_one_layer_2024.stderr b/tests/ui/match/ref_pat_eat_one_layer_2024/feature-gate-ref_pat_eat_one_layer_2024.stderr new file mode 100644 index 00000000000..132fe421a18 --- /dev/null +++ b/tests/ui/match/ref_pat_eat_one_layer_2024/feature-gate-ref_pat_eat_one_layer_2024.stderr @@ -0,0 +1,128 @@ +error[E0308]: mismatched types + --> $DIR/feature-gate-ref_pat_eat_one_layer_2024.rs:5:22 + | +LL | if let Some(Some(&x)) = &Some(&Some(0)) { + | ^^ --------------- this expression has type `&Option<&Option<{integer}>>` + | | + | expected integer, found `&_` + | + = note: expected type `{integer}` + found reference `&_` +help: consider removing `&` from the pattern + | +LL | if let Some(Some(x)) = &Some(&Some(0)) { + | ~ + +error[E0308]: mismatched types + --> $DIR/feature-gate-ref_pat_eat_one_layer_2024.rs:10:23 + | +LL | let _: &u32 = x; + | ---- ^ expected `&u32`, found integer + | | + | expected due to this + | +help: consider borrowing here + | +LL | let _: &u32 = &x; + | + + +error[E0308]: mismatched types + --> $DIR/feature-gate-ref_pat_eat_one_layer_2024.rs:13:23 + | +LL | if let Some(Some(&&x)) = &Some(Some(&0)) { + | ^^ --------------- this expression has type `&Option>` + | | + | expected integer, found `&_` + | + = note: expected type `{integer}` + found reference `&_` +help: consider removing `&` from the pattern + | +LL - if let Some(Some(&&x)) = &Some(Some(&0)) { +LL + if let Some(Some(&x)) = &Some(Some(&0)) { + | + +error[E0308]: mismatched types + --> $DIR/feature-gate-ref_pat_eat_one_layer_2024.rs:17:17 + | +LL | if let Some(&Some(x)) = &Some(Some(0)) { + | ^^^^^^^^ -------------- this expression has type `&Option>` + | | + | expected `Option<{integer}>`, found `&_` + | + = note: expected enum `Option<{integer}>` + found reference `&_` + +error[E0308]: mismatched types + --> $DIR/feature-gate-ref_pat_eat_one_layer_2024.rs:21:22 + | +LL | if let Some(Some(&mut x)) = &mut Some(&mut Some(0)) { + | ^^^^^^ ----------------------- this expression has type `&mut Option<&mut Option<{integer}>>` + | | + | expected integer, found `&mut _` + | + = note: expected type `{integer}` + found mutable reference `&mut _` +note: to declare a mutable binding use: `mut x` + --> $DIR/feature-gate-ref_pat_eat_one_layer_2024.rs:21:22 + | +LL | if let Some(Some(&mut x)) = &mut Some(&mut Some(0)) { + | ^^^^^^ +help: consider removing `&mut` from the pattern + | +LL | if let Some(Some(x)) = &mut Some(&mut Some(0)) { + | ~ + +error[E0308]: mismatched types + --> $DIR/feature-gate-ref_pat_eat_one_layer_2024.rs:25:22 + | +LL | if let Some(Some(&x)) = &Some(&Some(0)) { + | ^^ --------------- this expression has type `&Option<&Option<{integer}>>` + | | + | expected integer, found `&_` + | + = note: expected type `{integer}` + found reference `&_` +help: consider removing `&` from the pattern + | +LL | if let Some(Some(x)) = &Some(&Some(0)) { + | ~ + +error[E0308]: mismatched types + --> $DIR/feature-gate-ref_pat_eat_one_layer_2024.rs:29:27 + | +LL | if let Some(&mut Some(&x)) = &Some(&mut Some(0)) { + | ^^ ------------------- this expression has type `&Option<&mut Option<{integer}>>` + | | + | expected integer, found `&_` + | + = note: expected type `{integer}` + found reference `&_` +help: consider removing `&` from the pattern + | +LL | if let Some(&mut Some(x)) = &Some(&mut Some(0)) { + | ~ + +error[E0308]: mismatched types + --> $DIR/feature-gate-ref_pat_eat_one_layer_2024.rs:33:23 + | +LL | if let Some(&Some(&mut x)) = &mut Some(&Some(0)) { + | ^^^^^^ ------------------- this expression has type `&mut Option<&Option<{integer}>>` + | | + | expected integer, found `&mut _` + | + = note: expected type `{integer}` + found mutable reference `&mut _` +note: to declare a mutable binding use: `mut x` + --> $DIR/feature-gate-ref_pat_eat_one_layer_2024.rs:33:23 + | +LL | if let Some(&Some(&mut x)) = &mut Some(&Some(0)) { + | ^^^^^^ +help: consider removing `&mut` from the pattern + | +LL | if let Some(&Some(x)) = &mut Some(&Some(0)) { + | ~ + +error: aborting due to 8 previous errors + +For more information about this error, try `rustc --explain E0308`. diff --git a/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2021.rs b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2021.rs new file mode 100644 index 00000000000..d28567f2859 --- /dev/null +++ b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2021.rs @@ -0,0 +1,37 @@ +//@ edition: 2021 +#![allow(incomplete_features)] +#![feature(ref_pat_eat_one_layer_2024)] +pub fn main() { + if let Some(Some(&x)) = &Some(&Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(Some(&x)) = &Some(Some(&0)) { + let _: &u32 = x; + //~^ ERROR: mismatched types + } + if let Some(Some(&&x)) = &Some(Some(&0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(&Some(x)) = &Some(Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(Some(&mut x)) = &mut Some(&mut Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(Some(&x)) = &Some(&Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(&mut Some(&x)) = &Some(&mut Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } + if let Some(&Some(&mut x)) = &mut Some(&Some(0)) { + //~^ ERROR: mismatched types + let _: u32 = x; + } +} diff --git a/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2021.stderr b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2021.stderr new file mode 100644 index 00000000000..28706f89c06 --- /dev/null +++ b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2021.stderr @@ -0,0 +1,128 @@ +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2021.rs:5:22 + | +LL | if let Some(Some(&x)) = &Some(&Some(0)) { + | ^^ --------------- this expression has type `&Option<&Option<{integer}>>` + | | + | expected integer, found `&_` + | + = note: expected type `{integer}` + found reference `&_` +help: consider removing `&` from the pattern + | +LL | if let Some(Some(x)) = &Some(&Some(0)) { + | ~ + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2021.rs:10:23 + | +LL | let _: &u32 = x; + | ---- ^ expected `&u32`, found integer + | | + | expected due to this + | +help: consider borrowing here + | +LL | let _: &u32 = &x; + | + + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2021.rs:13:23 + | +LL | if let Some(Some(&&x)) = &Some(Some(&0)) { + | ^^ --------------- this expression has type `&Option>` + | | + | expected integer, found `&_` + | + = note: expected type `{integer}` + found reference `&_` +help: consider removing `&` from the pattern + | +LL - if let Some(Some(&&x)) = &Some(Some(&0)) { +LL + if let Some(Some(&x)) = &Some(Some(&0)) { + | + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2021.rs:17:17 + | +LL | if let Some(&Some(x)) = &Some(Some(0)) { + | ^^^^^^^^ -------------- this expression has type `&Option>` + | | + | expected `Option<{integer}>`, found `&_` + | + = note: expected enum `Option<{integer}>` + found reference `&_` + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2021.rs:21:22 + | +LL | if let Some(Some(&mut x)) = &mut Some(&mut Some(0)) { + | ^^^^^^ ----------------------- this expression has type `&mut Option<&mut Option<{integer}>>` + | | + | expected integer, found `&mut _` + | + = note: expected type `{integer}` + found mutable reference `&mut _` +note: to declare a mutable binding use: `mut x` + --> $DIR/ref_pat_eat_one_layer_2021.rs:21:22 + | +LL | if let Some(Some(&mut x)) = &mut Some(&mut Some(0)) { + | ^^^^^^ +help: consider removing `&mut` from the pattern + | +LL | if let Some(Some(x)) = &mut Some(&mut Some(0)) { + | ~ + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2021.rs:25:22 + | +LL | if let Some(Some(&x)) = &Some(&Some(0)) { + | ^^ --------------- this expression has type `&Option<&Option<{integer}>>` + | | + | expected integer, found `&_` + | + = note: expected type `{integer}` + found reference `&_` +help: consider removing `&` from the pattern + | +LL | if let Some(Some(x)) = &Some(&Some(0)) { + | ~ + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2021.rs:29:27 + | +LL | if let Some(&mut Some(&x)) = &Some(&mut Some(0)) { + | ^^ ------------------- this expression has type `&Option<&mut Option<{integer}>>` + | | + | expected integer, found `&_` + | + = note: expected type `{integer}` + found reference `&_` +help: consider removing `&` from the pattern + | +LL | if let Some(&mut Some(x)) = &Some(&mut Some(0)) { + | ~ + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2021.rs:33:23 + | +LL | if let Some(&Some(&mut x)) = &mut Some(&Some(0)) { + | ^^^^^^ ------------------- this expression has type `&mut Option<&Option<{integer}>>` + | | + | expected integer, found `&mut _` + | + = note: expected type `{integer}` + found mutable reference `&mut _` +note: to declare a mutable binding use: `mut x` + --> $DIR/ref_pat_eat_one_layer_2021.rs:33:23 + | +LL | if let Some(&Some(&mut x)) = &mut Some(&Some(0)) { + | ^^^^^^ +help: consider removing `&mut` from the pattern + | +LL | if let Some(&Some(x)) = &mut Some(&Some(0)) { + | ~ + +error: aborting due to 8 previous errors + +For more information about this error, try `rustc --explain E0308`. 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 new file mode 100644 index 00000000000..f8378427383 --- /dev/null +++ b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024.rs @@ -0,0 +1,32 @@ +//@ run-pass +//@ edition: 2024 +//@ compile-flags: -Zunstable-options +#![allow(incomplete_features)] +#![feature(ref_pat_eat_one_layer_2024)] + +pub fn main() { + if let Some(Some(&x)) = &Some(&Some(0)) { + let _: u32 = x; + } + if let Some(Some(&x)) = &Some(Some(&0)) { + let _: &u32 = x; + } + if let Some(Some(&&x)) = &Some(Some(&0)) { + let _: u32 = x; + } + if let Some(&Some(x)) = &Some(Some(0)) { + let _: u32 = x; + } + if let Some(Some(&mut x)) = &mut Some(&mut Some(0)) { + let _: u32 = x; + } + 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(&mut x)) = &mut Some(& Some(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 new file mode 100644 index 00000000000..566196c1a32 --- /dev/null +++ b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024_fail.rs @@ -0,0 +1,13 @@ +//@ edition: 2024 +//@ compile-flags: -Zunstable-options +#![allow(incomplete_features)] +#![feature(ref_pat_eat_one_layer_2024)] + +pub fn main() { + if let Some(&mut Some(&_)) = &Some(&Some(0)) { + //~^ ERROR: mismatched types + } + if let Some(&Some(&_)) = &Some(&mut Some(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 new file mode 100644 index 00000000000..96a107b5c50 --- /dev/null +++ b/tests/ui/match/ref_pat_eat_one_layer_2024/ref_pat_eat_one_layer_2024_fail.stderr @@ -0,0 +1,25 @@ +error[E0308]: mismatched types + --> $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}>>` + | | + | types differ in mutability + | + = note: expected reference `&Option<{integer}>` + found mutable reference `&mut _` + +error[E0308]: mismatched types + --> $DIR/ref_pat_eat_one_layer_2024_fail.rs:10:23 + | +LL | if let Some(&Some(&_)) = &Some(&mut Some(0)) { + | ^^ ------------------- this expression has type `&Option<&mut Option<{integer}>>` + | | + | expected integer, found `&_` + | + = note: expected type `{integer}` + found reference `&_` + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0308`.