diff --git a/compiler/rustc_hir_typeck/src/expr_use_visitor.rs b/compiler/rustc_hir_typeck/src/expr_use_visitor.rs index 27b66d07f98e..2e993cf7db95 100644 --- a/compiler/rustc_hir_typeck/src/expr_use_visitor.rs +++ b/compiler/rustc_hir_typeck/src/expr_use_visitor.rs @@ -943,6 +943,19 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx } /// The core driver for walking a pattern + /// + /// This should mirror how pattern-matching gets lowered to MIR, as + /// otherwise lowering will ICE when trying to resolve the upvars. + /// + /// However, it is okay to approximate it here by doing *more* accesses than + /// the actual MIR builder will, which is useful when some checks are too + /// cumbersome to perform here. For example, if after typeck it becomes + /// clear that only one variant of an enum is inhabited, and therefore a + /// read of the discriminant is not necessary, `walk_pat` will have + /// over-approximated the necessary upvar capture granularity. + /// + /// Do note that discrepancies like these do still create obscure corners + /// in the semantics of the language, and should be avoided if possible. #[instrument(skip(self), level = "debug")] fn walk_pat( &self, @@ -952,6 +965,11 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx ) -> Result<(), Cx::Error> { let tcx = self.cx.tcx(); self.cat_pattern(discr_place.clone(), pat, &mut |place, pat| { + debug!("walk_pat: pat.kind={:?}", pat.kind); + let read_discriminant = || { + self.delegate.borrow_mut().borrow(place, discr_place.hir_id, BorrowKind::Immutable); + }; + match pat.kind { PatKind::Binding(_, canonical_id, ..) => { debug!("walk_pat: binding place={:?} pat={:?}", place, pat); @@ -974,11 +992,7 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx // binding when lowering pattern guards to ensure that the guard does not // modify the scrutinee. if has_guard { - self.delegate.borrow_mut().borrow( - place, - discr_place.hir_id, - BorrowKind::Immutable, - ); + read_discriminant(); } // It is also a borrow or copy/move of the value being matched. @@ -1014,13 +1028,71 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx PatKind::Never => { // A `!` pattern always counts as an immutable read of the discriminant, // even in an irrefutable pattern. - self.delegate.borrow_mut().borrow( - place, - discr_place.hir_id, - BorrowKind::Immutable, - ); + read_discriminant(); + } + PatKind::Expr(PatExpr { kind: PatExprKind::Path(qpath), hir_id, span }) => { + // A `Path` pattern is just a name like `Foo`. This is either a + // named constant or else it refers to an ADT variant + + let res = self.cx.typeck_results().qpath_res(qpath, *hir_id); + match res { + Res::Def(DefKind::Const, _) | Res::Def(DefKind::AssocConst, _) => { + // Named constants have to be equated with the value + // being matched, so that's a read of the value being matched. + // + // FIXME: Does the MIR code skip this read when matching on a ZST? + // If so, we can also skip it here. + read_discriminant(); + } + _ => { + // Otherwise, this is a struct/enum variant, and so it's + // only a read if we need to read the discriminant. + if self.is_multivariant_adt(place.place.ty(), *span) { + read_discriminant(); + } + } + } + } + PatKind::Expr(_) | PatKind::Range(..) => { + // When matching against a literal or range, we need to + // borrow the place to compare it against the pattern. + // + // FIXME: What if the type being matched only has one + // possible value? + // FIXME: What if the range is the full range of the type + // and doesn't actually require a discriminant read? + read_discriminant(); + } + PatKind::Struct(..) | PatKind::TupleStruct(..) => { + if self.is_multivariant_adt(place.place.ty(), pat.span) { + read_discriminant(); + } + } + PatKind::Slice(lhs, wild, rhs) => { + // We don't need to test the length if the pattern is `[..]` + if matches!((lhs, wild, rhs), (&[], Some(_), &[])) + // Arrays have a statically known size, so + // there is no need to read their length + || place.place.ty().peel_refs().is_array() + { + // No read necessary + } else { + read_discriminant(); + } + } + PatKind::Or(_) + | PatKind::Box(_) + | PatKind::Ref(..) + | PatKind::Guard(..) + | PatKind::Tuple(..) + | PatKind::Wild + | PatKind::Missing + | PatKind::Err(_) => { + // If the PatKind is Or, Box, Ref, Guard, or Tuple, the relevant accesses + // are made later as these patterns contains subpatterns. + // If the PatKind is Missing, Wild or Err, any relevant accesses are made when processing + // the other patterns that are part of the match } - _ => {} } Ok(()) @@ -1904,6 +1976,14 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx } } + /// Checks whether a type has multiple variants, and therefore, whether a + /// read of the discriminant might be necessary. Note that the actual MIR + /// builder code does a more specific check, filtering out variants that + /// happen to be uninhabited. + /// + /// Here, we cannot perform such an accurate checks, because querying + /// whether a type is inhabited requires that it has been fully inferred, + /// which cannot be guaranteed at this point. fn is_multivariant_adt(&self, ty: Ty<'tcx>, span: Span) -> bool { if let ty::Adt(def, _) = self.cx.structurally_resolve_type(span, ty).kind() { // Note that if a non-exhaustive SingleVariant is defined in another crate, we need diff --git a/tests/crashes/137467-1.rs b/tests/crashes/137467-1.rs deleted file mode 100644 index b6bff2bdc4e8..000000000000 --- a/tests/crashes/137467-1.rs +++ /dev/null @@ -1,17 +0,0 @@ -//@ known-bug: #137467 -//@ edition: 2021 -enum Camera { - Normal { base_transform: i32 }, - Volume { transform: i32 }, -} - -fn draw_ui(camera: &mut Camera) { - || { - let (Camera::Normal { - base_transform: _transform, - } - | Camera::Volume { - transform: _transform, - }) = camera; - }; -} diff --git a/tests/crashes/137467-2.rs b/tests/crashes/137467-2.rs deleted file mode 100644 index a70ea92b22dc..000000000000 --- a/tests/crashes/137467-2.rs +++ /dev/null @@ -1,18 +0,0 @@ -//@ known-bug: #137467 -//@ edition: 2021 - -enum Camera { - Normal { base_transform: i32 }, - Volume { transform: i32 }, -} - -fn draw_ui(camera: &mut Camera) { - || { - let (Camera::Normal { - base_transform: _, - } - | Camera::Volume { - transform: _, - }) = camera; - }; -} diff --git a/tests/crashes/137467-3.rs b/tests/crashes/137467-3.rs deleted file mode 100644 index cb81a9a912e7..000000000000 --- a/tests/crashes/137467-3.rs +++ /dev/null @@ -1,8 +0,0 @@ -//@ known-bug: #137467 -//@ edition: 2021 - -fn meow(x: (u32, u32, u32)) { - let f = || { - let ((0, a, _) | (_, _, a)) = x; - }; -} diff --git a/tests/ui/closures/2229_closure_analysis/capture-enums.rs b/tests/ui/closures/2229_closure_analysis/capture-enums.rs index d9c06a68c95b..4c600ccdaa43 100644 --- a/tests/ui/closures/2229_closure_analysis/capture-enums.rs +++ b/tests/ui/closures/2229_closure_analysis/capture-enums.rs @@ -22,6 +22,7 @@ fn multi_variant_enum() { //~| ERROR Min Capture analysis includes: if let Info::Point(_, _, str) = point { //~^ NOTE: Capturing point[] -> Immutable + //~| NOTE: Capturing point[] -> Immutable //~| NOTE: Capturing point[(2, 0)] -> ByValue //~| NOTE: Min Capture point[] -> ByValue println!("{}", str); @@ -29,6 +30,7 @@ fn multi_variant_enum() { if let Info::Meta(_, v) = meta { //~^ NOTE: Capturing meta[] -> Immutable + //~| NOTE: Capturing meta[] -> Immutable //~| NOTE: Capturing meta[(1, 1)] -> ByValue //~| NOTE: Min Capture meta[] -> ByValue println!("{:?}", v); diff --git a/tests/ui/closures/2229_closure_analysis/capture-enums.stderr b/tests/ui/closures/2229_closure_analysis/capture-enums.stderr index 89a879cec468..b62384ffe12e 100644 --- a/tests/ui/closures/2229_closure_analysis/capture-enums.stderr +++ b/tests/ui/closures/2229_closure_analysis/capture-enums.stderr @@ -9,7 +9,7 @@ LL | let c = #[rustc_capture_analysis] = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error[E0658]: attributes on expressions are experimental - --> $DIR/capture-enums.rs:48:13 + --> $DIR/capture-enums.rs:50:13 | LL | let c = #[rustc_capture_analysis] | ^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -34,18 +34,28 @@ note: Capturing point[] -> Immutable | LL | if let Info::Point(_, _, str) = point { | ^^^^^ +note: Capturing point[] -> Immutable + --> $DIR/capture-enums.rs:23:41 + | +LL | if let Info::Point(_, _, str) = point { + | ^^^^^ note: Capturing point[(2, 0)] -> ByValue --> $DIR/capture-enums.rs:23:41 | LL | if let Info::Point(_, _, str) = point { | ^^^^^ note: Capturing meta[] -> Immutable - --> $DIR/capture-enums.rs:30:35 + --> $DIR/capture-enums.rs:31:35 + | +LL | if let Info::Meta(_, v) = meta { + | ^^^^ +note: Capturing meta[] -> Immutable + --> $DIR/capture-enums.rs:31:35 | LL | if let Info::Meta(_, v) = meta { | ^^^^ note: Capturing meta[(1, 1)] -> ByValue - --> $DIR/capture-enums.rs:30:35 + --> $DIR/capture-enums.rs:31:35 | LL | if let Info::Meta(_, v) = meta { | ^^^^ @@ -67,13 +77,13 @@ note: Min Capture point[] -> ByValue LL | if let Info::Point(_, _, str) = point { | ^^^^^ note: Min Capture meta[] -> ByValue - --> $DIR/capture-enums.rs:30:35 + --> $DIR/capture-enums.rs:31:35 | LL | if let Info::Meta(_, v) = meta { | ^^^^ error: First Pass analysis includes: - --> $DIR/capture-enums.rs:52:5 + --> $DIR/capture-enums.rs:54:5 | LL | / || { LL | | @@ -85,13 +95,13 @@ LL | | }; | |_____^ | note: Capturing point[(2, 0)] -> ByValue - --> $DIR/capture-enums.rs:55:47 + --> $DIR/capture-enums.rs:57:47 | LL | let SingleVariant::Point(_, _, str) = point; | ^^^^^ error: Min Capture analysis includes: - --> $DIR/capture-enums.rs:52:5 + --> $DIR/capture-enums.rs:54:5 | LL | / || { LL | | @@ -103,7 +113,7 @@ LL | | }; | |_____^ | note: Min Capture point[(2, 0)] -> ByValue - --> $DIR/capture-enums.rs:55:47 + --> $DIR/capture-enums.rs:57:47 | LL | let SingleVariant::Point(_, _, str) = point; | ^^^^^ diff --git a/tests/ui/closures/2229_closure_analysis/match/patterns-capture-analysis.rs b/tests/ui/closures/2229_closure_analysis/match/patterns-capture-analysis.rs index 40330af4088c..a9d2777d93f1 100644 --- a/tests/ui/closures/2229_closure_analysis/match/patterns-capture-analysis.rs +++ b/tests/ui/closures/2229_closure_analysis/match/patterns-capture-analysis.rs @@ -14,6 +14,7 @@ fn test_1_should_capture() { //~| ERROR Min Capture analysis includes: match variant { //~^ NOTE: Capturing variant[] -> Immutable + //~| NOTE: Capturing variant[] -> Immutable //~| NOTE: Min Capture variant[] -> Immutable Some(_) => {} _ => {} @@ -132,6 +133,7 @@ fn test_5_should_capture_multi_variant() { //~| ERROR Min Capture analysis includes: match variant { //~^ NOTE: Capturing variant[] -> Immutable + //~| NOTE: Capturing variant[] -> Immutable //~| NOTE: Min Capture variant[] -> Immutable MVariant::A => {} _ => {} @@ -150,6 +152,7 @@ fn test_7_should_capture_slice_len() { //~| ERROR Min Capture analysis includes: match slice { //~^ NOTE: Capturing slice[] -> Immutable + //~| NOTE: Capturing slice[Deref] -> Immutable //~| NOTE: Min Capture slice[] -> Immutable [_,_,_] => {}, _ => {} @@ -162,6 +165,7 @@ fn test_7_should_capture_slice_len() { //~| ERROR Min Capture analysis includes: match slice { //~^ NOTE: Capturing slice[] -> Immutable + //~| NOTE: Capturing slice[Deref] -> Immutable //~| NOTE: Min Capture slice[] -> Immutable [] => {}, _ => {} @@ -174,6 +178,7 @@ fn test_7_should_capture_slice_len() { //~| ERROR Min Capture analysis includes: match slice { //~^ NOTE: Capturing slice[] -> Immutable + //~| NOTE: Capturing slice[Deref] -> Immutable //~| NOTE: Min Capture slice[] -> Immutable [_, .. ,_] => {}, _ => {} diff --git a/tests/ui/closures/2229_closure_analysis/match/patterns-capture-analysis.stderr b/tests/ui/closures/2229_closure_analysis/match/patterns-capture-analysis.stderr index e7e5e7f7fa1b..4b9d6fad0e50 100644 --- a/tests/ui/closures/2229_closure_analysis/match/patterns-capture-analysis.stderr +++ b/tests/ui/closures/2229_closure_analysis/match/patterns-capture-analysis.stderr @@ -14,6 +14,11 @@ note: Capturing variant[] -> Immutable | LL | match variant { | ^^^^^^^ +note: Capturing variant[] -> Immutable + --> $DIR/patterns-capture-analysis.rs:15:15 + | +LL | match variant { + | ^^^^^^^ error: Min Capture analysis includes: --> $DIR/patterns-capture-analysis.rs:12:5 @@ -33,7 +38,7 @@ LL | match variant { | ^^^^^^^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:30:5 + --> $DIR/patterns-capture-analysis.rs:31:5 | LL | / || { LL | | @@ -44,7 +49,7 @@ LL | | }; | |_____^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:49:5 + --> $DIR/patterns-capture-analysis.rs:50:5 | LL | / || { LL | | @@ -55,7 +60,7 @@ LL | | }; | |_____^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:63:5 + --> $DIR/patterns-capture-analysis.rs:64:5 | LL | / || { LL | | @@ -66,18 +71,18 @@ LL | | }; | |_____^ | note: Capturing variant[] -> Immutable - --> $DIR/patterns-capture-analysis.rs:66:15 + --> $DIR/patterns-capture-analysis.rs:67:15 | LL | match variant { | ^^^^^^^ note: Capturing variant[(0, 0)] -> Immutable - --> $DIR/patterns-capture-analysis.rs:66:15 + --> $DIR/patterns-capture-analysis.rs:67:15 | LL | match variant { | ^^^^^^^ error: Min Capture analysis includes: - --> $DIR/patterns-capture-analysis.rs:63:5 + --> $DIR/patterns-capture-analysis.rs:64:5 | LL | / || { LL | | @@ -88,13 +93,13 @@ LL | | }; | |_____^ | note: Min Capture variant[] -> Immutable - --> $DIR/patterns-capture-analysis.rs:66:15 + --> $DIR/patterns-capture-analysis.rs:67:15 | LL | match variant { | ^^^^^^^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:83:5 + --> $DIR/patterns-capture-analysis.rs:84:5 | LL | / || { LL | | @@ -105,7 +110,7 @@ LL | | }; | |_____^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:95:5 + --> $DIR/patterns-capture-analysis.rs:96:5 | LL | / || { LL | | @@ -116,7 +121,7 @@ LL | | }; | |_____^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:108:5 + --> $DIR/patterns-capture-analysis.rs:109:5 | LL | / || { LL | | @@ -127,7 +132,7 @@ LL | | }; | |_____^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:130:5 + --> $DIR/patterns-capture-analysis.rs:131:5 | LL | / || { LL | | @@ -138,13 +143,18 @@ LL | | }; | |_____^ | note: Capturing variant[] -> Immutable - --> $DIR/patterns-capture-analysis.rs:133:15 + --> $DIR/patterns-capture-analysis.rs:134:15 + | +LL | match variant { + | ^^^^^^^ +note: Capturing variant[] -> Immutable + --> $DIR/patterns-capture-analysis.rs:134:15 | LL | match variant { | ^^^^^^^ error: Min Capture analysis includes: - --> $DIR/patterns-capture-analysis.rs:130:5 + --> $DIR/patterns-capture-analysis.rs:131:5 | LL | / || { LL | | @@ -155,13 +165,13 @@ LL | | }; | |_____^ | note: Min Capture variant[] -> Immutable - --> $DIR/patterns-capture-analysis.rs:133:15 + --> $DIR/patterns-capture-analysis.rs:134:15 | LL | match variant { | ^^^^^^^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:148:5 + --> $DIR/patterns-capture-analysis.rs:150:5 | LL | / || { LL | | @@ -172,13 +182,18 @@ LL | | }; | |_____^ | note: Capturing slice[] -> Immutable - --> $DIR/patterns-capture-analysis.rs:151:15 + --> $DIR/patterns-capture-analysis.rs:153:15 + | +LL | match slice { + | ^^^^^ +note: Capturing slice[Deref] -> Immutable + --> $DIR/patterns-capture-analysis.rs:153:15 | LL | match slice { | ^^^^^ error: Min Capture analysis includes: - --> $DIR/patterns-capture-analysis.rs:148:5 + --> $DIR/patterns-capture-analysis.rs:150:5 | LL | / || { LL | | @@ -189,13 +204,13 @@ LL | | }; | |_____^ | note: Min Capture slice[] -> Immutable - --> $DIR/patterns-capture-analysis.rs:151:15 + --> $DIR/patterns-capture-analysis.rs:153:15 | LL | match slice { | ^^^^^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:160:5 + --> $DIR/patterns-capture-analysis.rs:163:5 | LL | / || { LL | | @@ -206,13 +221,18 @@ LL | | }; | |_____^ | note: Capturing slice[] -> Immutable - --> $DIR/patterns-capture-analysis.rs:163:15 + --> $DIR/patterns-capture-analysis.rs:166:15 + | +LL | match slice { + | ^^^^^ +note: Capturing slice[Deref] -> Immutable + --> $DIR/patterns-capture-analysis.rs:166:15 | LL | match slice { | ^^^^^ error: Min Capture analysis includes: - --> $DIR/patterns-capture-analysis.rs:160:5 + --> $DIR/patterns-capture-analysis.rs:163:5 | LL | / || { LL | | @@ -223,13 +243,13 @@ LL | | }; | |_____^ | note: Min Capture slice[] -> Immutable - --> $DIR/patterns-capture-analysis.rs:163:15 + --> $DIR/patterns-capture-analysis.rs:166:15 | LL | match slice { | ^^^^^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:172:5 + --> $DIR/patterns-capture-analysis.rs:176:5 | LL | / || { LL | | @@ -240,13 +260,18 @@ LL | | }; | |_____^ | note: Capturing slice[] -> Immutable - --> $DIR/patterns-capture-analysis.rs:175:15 + --> $DIR/patterns-capture-analysis.rs:179:15 + | +LL | match slice { + | ^^^^^ +note: Capturing slice[Deref] -> Immutable + --> $DIR/patterns-capture-analysis.rs:179:15 | LL | match slice { | ^^^^^ error: Min Capture analysis includes: - --> $DIR/patterns-capture-analysis.rs:172:5 + --> $DIR/patterns-capture-analysis.rs:176:5 | LL | / || { LL | | @@ -257,13 +282,13 @@ LL | | }; | |_____^ | note: Min Capture slice[] -> Immutable - --> $DIR/patterns-capture-analysis.rs:175:15 + --> $DIR/patterns-capture-analysis.rs:179:15 | LL | match slice { | ^^^^^ error: First Pass analysis includes: - --> $DIR/patterns-capture-analysis.rs:189:5 + --> $DIR/patterns-capture-analysis.rs:194:5 | LL | / || { LL | | diff --git a/tests/ui/closures/2229_closure_analysis/only-inhabited-variant-stable.rs b/tests/ui/closures/2229_closure_analysis/only-inhabited-variant-stable.rs new file mode 100644 index 000000000000..a8e4b9cd1823 --- /dev/null +++ b/tests/ui/closures/2229_closure_analysis/only-inhabited-variant-stable.rs @@ -0,0 +1,23 @@ +// This example used to compile, but the fact that it should was never properly +// discussed. With further experience, we concluded that capture precision +// depending on whether some types are inhabited goes too far, introducing a +// bunch of headaches without much benefit. +//@ edition:2021 +#[derive(Clone, Copy, PartialEq, Eq, Debug)] +enum Void {} + +pub fn main() { + let mut r = Result::::Err((0, 0)); + let mut f = || { + let Err((ref mut a, _)) = r; + *a = 1; + }; + let mut g = || { + //~^ ERROR: cannot borrow `r` as mutable more than once at a time + let Err((_, ref mut b)) = r; + *b = 2; + }; + f(); + g(); + assert_eq!(r, Err((1, 2))); +} diff --git a/tests/ui/closures/2229_closure_analysis/only-inhabited-variant-stable.stderr b/tests/ui/closures/2229_closure_analysis/only-inhabited-variant-stable.stderr new file mode 100644 index 000000000000..dea85ff947ce --- /dev/null +++ b/tests/ui/closures/2229_closure_analysis/only-inhabited-variant-stable.stderr @@ -0,0 +1,20 @@ +error[E0499]: cannot borrow `r` as mutable more than once at a time + --> $DIR/only-inhabited-variant-stable.rs:15:17 + | +LL | let mut f = || { + | -- first mutable borrow occurs here +LL | let Err((ref mut a, _)) = r; + | - first borrow occurs due to use of `r` in closure +... +LL | let mut g = || { + | ^^ second mutable borrow occurs here +LL | +LL | let Err((_, ref mut b)) = r; + | - second borrow occurs due to use of `r` in closure +... +LL | f(); + | - first borrow later used here + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0499`. diff --git a/tests/ui/closures/2229_closure_analysis/only-inhabited-variant.exhaustive_patterns.stderr b/tests/ui/closures/2229_closure_analysis/only-inhabited-variant.exhaustive_patterns.stderr new file mode 100644 index 000000000000..58a5348aa391 --- /dev/null +++ b/tests/ui/closures/2229_closure_analysis/only-inhabited-variant.exhaustive_patterns.stderr @@ -0,0 +1,20 @@ +error[E0499]: cannot borrow `r` as mutable more than once at a time + --> $DIR/only-inhabited-variant.rs:16:17 + | +LL | let mut f = || { + | -- first mutable borrow occurs here +LL | let Err((ref mut a, _)) = r; + | - first borrow occurs due to use of `r` in closure +... +LL | let mut g = || { + | ^^ second mutable borrow occurs here +LL | +LL | let Err((_, ref mut b)) = r; + | - second borrow occurs due to use of `r` in closure +... +LL | f(); + | - first borrow later used here + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0499`. diff --git a/tests/ui/closures/2229_closure_analysis/only-inhabited-variant.normal.stderr b/tests/ui/closures/2229_closure_analysis/only-inhabited-variant.normal.stderr new file mode 100644 index 000000000000..58a5348aa391 --- /dev/null +++ b/tests/ui/closures/2229_closure_analysis/only-inhabited-variant.normal.stderr @@ -0,0 +1,20 @@ +error[E0499]: cannot borrow `r` as mutable more than once at a time + --> $DIR/only-inhabited-variant.rs:16:17 + | +LL | let mut f = || { + | -- first mutable borrow occurs here +LL | let Err((ref mut a, _)) = r; + | - first borrow occurs due to use of `r` in closure +... +LL | let mut g = || { + | ^^ second mutable borrow occurs here +LL | +LL | let Err((_, ref mut b)) = r; + | - second borrow occurs due to use of `r` in closure +... +LL | f(); + | - first borrow later used here + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0499`. diff --git a/tests/ui/closures/2229_closure_analysis/run_pass/multivariant.rs b/tests/ui/closures/2229_closure_analysis/only-inhabited-variant.rs similarity index 55% rename from tests/ui/closures/2229_closure_analysis/run_pass/multivariant.rs rename to tests/ui/closures/2229_closure_analysis/only-inhabited-variant.rs index 74f37b514e4a..463838734726 100644 --- a/tests/ui/closures/2229_closure_analysis/run_pass/multivariant.rs +++ b/tests/ui/closures/2229_closure_analysis/only-inhabited-variant.rs @@ -1,8 +1,9 @@ -// Test precise capture of a multi-variant enum (when remaining variants are -// visibly uninhabited). +// This example used to compile, but the fact that it should was never properly +// discussed. With further experience, we concluded that capture precision +// depending on whether some types are inhabited goes too far, introducing a +// bunch of headaches without much benefit. //@ revisions: normal exhaustive_patterns //@ edition:2021 -//@ run-pass #![cfg_attr(exhaustive_patterns, feature(exhaustive_patterns))] #![feature(never_type)] @@ -13,6 +14,7 @@ pub fn main() { *a = 1; }; let mut g = || { + //~^ ERROR: cannot borrow `r` as mutable more than once at a time let Err((_, ref mut b)) = r; *b = 2; }; diff --git a/tests/ui/closures/or-patterns-issue-137467.rs b/tests/ui/closures/or-patterns-issue-137467.rs new file mode 100644 index 000000000000..38144aa1e816 --- /dev/null +++ b/tests/ui/closures/or-patterns-issue-137467.rs @@ -0,0 +1,170 @@ +//@ edition:2024 +//@ check-pass + +const X: u32 = 0; + +fn match_literal(x: (u32, u32, u32)) { + let _ = || { + let ((0, a, _) | (_, _, a)) = x; + a + }; +} + +fn match_range(x: (u32, u32, u32)) { + let _ = || { + let ((0..5, a, _) | (_, _, a)) = x; + a + }; +} + +fn match_const(x: (u32, u32, u32)) { + let _ = || { + let ((X, a, _) | (_, _, a)) = x; + a + }; +} + +enum Choice { A, B } + +fn match_unit_variant(x: (Choice, u32, u32)) { + let _ = || { + let ((Choice::A, a, _) | (Choice::B, _, a)) = x; + a + }; +} + +struct Unit; + +fn match_unit_struct(mut x: (Unit, u32)) { + let r = &mut x.0; + let _ = || { + let (Unit, a) = x; + a + }; + + let _ = *r; +} + +enum Also { Unit } + +fn match_unit_enum(mut x: (Also, u32)) { + let r = &mut x.0; + let _ = || { + let (Also::Unit, a) = x; + a + }; + + let _ = *r; +} + +enum TEnum { + A(u32), + B(u32), +} + +enum SEnum { + A { a: u32 }, + B { a: u32 }, +} + +fn match_tuple_enum(x: TEnum) { + let _ = || { + let (TEnum::A(a) | TEnum::B(a)) = x; + a + }; +} + +fn match_struct_enum(x: SEnum) { + let _ = || { + let (SEnum::A { a } | SEnum::B { a }) = x; + a + }; +} + +enum TSingle { + A(u32, u32), +} + +enum SSingle { + A { a: u32, b: u32 }, +} + +struct TStruct(u32, u32); +struct SStruct { a: u32, b: u32 } + +fn match_struct(mut x: SStruct) { + let r = &mut x.a; + let _ = || { + let SStruct { b, .. } = x; + b + }; + + let _ = *r; +} + +fn match_tuple_struct(mut x: TStruct) { + let r = &mut x.0; + let _ = || { + let TStruct(_, a) = x; + a + }; + + let _ = *r; +} + +fn match_singleton(mut x: SSingle) { + let SSingle::A { a: ref mut r, .. } = x; + let _ = || { + let SSingle::A { b, .. } = x; + b + }; + + let _ = *r; +} + +fn match_tuple_singleton(mut x: TSingle) { + let TSingle::A(ref mut r, _) = x; + let _ = || { + let TSingle::A(_, a) = x; + a + }; + + let _ = *r; +} + +fn match_slice(x: (&[u32], u32, u32)) { + let _ = || { + let (([], a, _) | ([_, ..], _, a)) = x; + a + }; +} + +// Original testcase, for completeness +enum Camera { + Normal { base_transform: i32 }, + Volume { transform: i32 }, +} + +fn draw_ui(camera: &mut Camera) { + || { + let (Camera::Normal { + base_transform: _transform, + } + | Camera::Volume { + transform: _transform, + }) = camera; + }; +} + +fn draw_ui2(camera: &mut Camera) { + || { + let (Camera::Normal { + base_transform: _, + } + | Camera::Volume { + transform: _, + }) = camera; + }; +} + +fn main() {}