diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index daa0349789e..a6273b92e5d 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -701,7 +701,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
self.bind_pattern(
self.source_info(irrefutable_pat.span),
candidate,
- &fake_borrow_temps,
+ fake_borrow_temps.as_slice(),
irrefutable_pat.span,
None,
false,
@@ -1938,7 +1938,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let post_guard_block = self.bind_pattern(
self.source_info(pat.span),
guard_candidate,
- &fake_borrow_temps,
+ fake_borrow_temps.as_slice(),
expr_span,
None,
false,
@@ -2425,7 +2425,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let matching = this.bind_pattern(
this.source_info(pattern.span),
candidate,
- &fake_borrow_temps,
+ fake_borrow_temps.as_slice(),
initializer_span,
None,
true,
@@ -2434,7 +2434,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let failure = this.bind_pattern(
this.source_info(else_block_span),
wildcard,
- &fake_borrow_temps,
+ fake_borrow_temps.as_slice(),
initializer_span,
None,
true,
diff --git a/compiler/rustc_mir_build/src/build/matches/simplify.rs b/compiler/rustc_mir_build/src/build/matches/simplify.rs
index c610f85fd5f..a3fccb7c319 100644
--- a/compiler/rustc_mir_build/src/build/matches/simplify.rs
+++ b/compiler/rustc_mir_build/src/build/matches/simplify.rs
@@ -41,60 +41,30 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
// let y = x;
// }
//
- // We can't just reverse the binding order, because we must preserve pattern-order
- // otherwise, e.g. in `let (Some(a), Some(b)) = (x, y)`. Our rule then is: deepest-first,
- // and bindings at the same depth stay in source order.
- //
- // To do this, every time around the loop we prepend the newly found bindings to the
- // bindings we already had.
- //
- // example:
- // candidate.bindings = [1, 2, 3]
- // bindings in iter 1: [4, 5]
- // bindings in iter 2: [6, 7]
- //
- // final bindings: [6, 7, 4, 5, 1, 2, 3]
- let mut accumulated_bindings = mem::take(candidate_bindings);
- let mut simplified_match_pairs = Vec::new();
- // Repeatedly simplify match pairs until we're left with only unsimplifiable ones.
- loop {
- for mut match_pair in mem::take(match_pairs) {
- if let TestCase::Irrefutable { binding, ascription } = match_pair.test_case {
- if let Some(binding) = binding {
- candidate_bindings.push(binding);
- }
- if let Some(ascription) = ascription {
- candidate_ascriptions.push(ascription);
- }
- // Simplifiable pattern; we replace it with its subpairs and simplify further.
- match_pairs.append(&mut match_pair.subpairs);
- } else {
- // Unsimplifiable pattern; we recursively simplify its subpairs and don't
- // process it further.
- self.simplify_match_pairs(
- &mut match_pair.subpairs,
- candidate_bindings,
- candidate_ascriptions,
- );
- simplified_match_pairs.push(match_pair);
+ // We therefore lower bindings from left-to-right, except we lower the `x` in `x @ pat`
+ // after any bindings in `pat`. This doesn't work for or-patterns: the current structure of
+ // match lowering forces us to lower bindings inside or-patterns last.
+ for mut match_pair in mem::take(match_pairs) {
+ self.simplify_match_pairs(
+ &mut match_pair.subpairs,
+ candidate_bindings,
+ candidate_ascriptions,
+ );
+ if let TestCase::Irrefutable { binding, ascription } = match_pair.test_case {
+ if let Some(binding) = binding {
+ candidate_bindings.push(binding);
}
- }
-
- // This does: accumulated_bindings = candidate.bindings.take() ++ accumulated_bindings
- candidate_bindings.extend_from_slice(&accumulated_bindings);
- mem::swap(candidate_bindings, &mut accumulated_bindings);
- candidate_bindings.clear();
-
- if match_pairs.is_empty() {
- break;
+ if let Some(ascription) = ascription {
+ candidate_ascriptions.push(ascription);
+ }
+ // Simplifiable pattern; we replace it with its already simplified subpairs.
+ match_pairs.append(&mut match_pair.subpairs);
+ } else {
+ // Unsimplifiable pattern; we keep it.
+ match_pairs.push(match_pair);
}
}
- // Store computed bindings back in `candidate_bindings`.
- mem::swap(candidate_bindings, &mut accumulated_bindings);
- // Store simplified match pairs back in `match_pairs`.
- mem::swap(match_pairs, &mut simplified_match_pairs);
-
// Move or-patterns to the end, because they can result in us
// creating additional candidates, so we want to test them as
// late as possible.
diff --git a/tests/mir-opt/early_otherwise_branch.opt1.EarlyOtherwiseBranch.diff b/tests/mir-opt/early_otherwise_branch.opt1.EarlyOtherwiseBranch.diff
index 8b427cff677..7a374c5675a 100644
--- a/tests/mir-opt/early_otherwise_branch.opt1.EarlyOtherwiseBranch.diff
+++ b/tests/mir-opt/early_otherwise_branch.opt1.EarlyOtherwiseBranch.diff
@@ -51,13 +51,13 @@
- }
-
- bb3: {
- StorageLive(_9);
- _9 = (((_3.1: std::option::Option<u32>) as Some).0: u32);
StorageLive(_8);
_8 = (((_3.0: std::option::Option<u32>) as Some).0: u32);
+ StorageLive(_9);
+ _9 = (((_3.1: std::option::Option<u32>) as Some).0: u32);
_0 = const 0_u32;
- StorageDead(_8);
StorageDead(_9);
+ StorageDead(_8);
- goto -> bb4;
+ goto -> bb3;
}
diff --git a/tests/mir-opt/early_otherwise_branch.opt2.EarlyOtherwiseBranch.diff b/tests/mir-opt/early_otherwise_branch.opt2.EarlyOtherwiseBranch.diff
index 32a8dd8b8b4..95bcfe71792 100644
--- a/tests/mir-opt/early_otherwise_branch.opt2.EarlyOtherwiseBranch.diff
+++ b/tests/mir-opt/early_otherwise_branch.opt2.EarlyOtherwiseBranch.diff
@@ -57,13 +57,13 @@
- }
-
- bb4: {
- StorageLive(_10);
- _10 = (((_3.1: std::option::Option<u32>) as Some).0: u32);
StorageLive(_9);
_9 = (((_3.0: std::option::Option<u32>) as Some).0: u32);
+ StorageLive(_10);
+ _10 = (((_3.1: std::option::Option<u32>) as Some).0: u32);
_0 = const 0_u32;
- StorageDead(_9);
StorageDead(_10);
+ StorageDead(_9);
- goto -> bb6;
+ goto -> bb4;
}
diff --git a/tests/mir-opt/early_otherwise_branch.opt3.EarlyOtherwiseBranch.diff b/tests/mir-opt/early_otherwise_branch.opt3.EarlyOtherwiseBranch.diff
index cc16af721ca..e058c409cb5 100644
--- a/tests/mir-opt/early_otherwise_branch.opt3.EarlyOtherwiseBranch.diff
+++ b/tests/mir-opt/early_otherwise_branch.opt3.EarlyOtherwiseBranch.diff
@@ -51,13 +51,13 @@
- }
-
- bb3: {
- StorageLive(_9);
- _9 = (((_3.1: std::option::Option<bool>) as Some).0: bool);
StorageLive(_8);
_8 = (((_3.0: std::option::Option<u32>) as Some).0: u32);
+ StorageLive(_9);
+ _9 = (((_3.1: std::option::Option<bool>) as Some).0: bool);
_0 = const 0_u32;
- StorageDead(_8);
StorageDead(_9);
+ StorageDead(_8);
- goto -> bb4;
+ goto -> bb3;
}
diff --git a/tests/mir-opt/early_otherwise_branch_3_element_tuple.opt1.EarlyOtherwiseBranch.diff b/tests/mir-opt/early_otherwise_branch_3_element_tuple.opt1.EarlyOtherwiseBranch.diff
index eb8926d27ee..f98d68e6ffc 100644
--- a/tests/mir-opt/early_otherwise_branch_3_element_tuple.opt1.EarlyOtherwiseBranch.diff
+++ b/tests/mir-opt/early_otherwise_branch_3_element_tuple.opt1.EarlyOtherwiseBranch.diff
@@ -69,16 +69,16 @@
- bb4: {
+ bb3: {
- StorageLive(_13);
- _13 = (((_4.2: std::option::Option<u32>) as Some).0: u32);
- StorageLive(_12);
- _12 = (((_4.1: std::option::Option<u32>) as Some).0: u32);
StorageLive(_11);
_11 = (((_4.0: std::option::Option<u32>) as Some).0: u32);
+ StorageLive(_12);
+ _12 = (((_4.1: std::option::Option<u32>) as Some).0: u32);
+ StorageLive(_13);
+ _13 = (((_4.2: std::option::Option<u32>) as Some).0: u32);
_0 = const 0_u32;
- StorageDead(_11);
- StorageDead(_12);
StorageDead(_13);
+ StorageDead(_12);
+ StorageDead(_11);
- goto -> bb5;
+ goto -> bb4;
}
diff --git a/tests/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff b/tests/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff
index 6179bab11fe..a5b5659a31a 100644
--- a/tests/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff
+++ b/tests/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff
@@ -116,12 +116,12 @@
}
bb6: {
- StorageLive(_13);
- _39 = deref_copy (_4.1: &ViewportPercentageLength);
- _13 = (((*_39) as Vw).0: f32);
StorageLive(_12);
- _40 = deref_copy (_4.0: &ViewportPercentageLength);
- _12 = (((*_40) as Vw).0: f32);
+ _39 = deref_copy (_4.0: &ViewportPercentageLength);
+ _12 = (((*_39) as Vw).0: f32);
+ StorageLive(_13);
+ _40 = deref_copy (_4.1: &ViewportPercentageLength);
+ _13 = (((*_40) as Vw).0: f32);
StorageLive(_14);
StorageLive(_15);
_15 = _12;
@@ -132,18 +132,18 @@
StorageDead(_15);
_3 = ViewportPercentageLength::Vw(move _14);
StorageDead(_14);
- StorageDead(_12);
StorageDead(_13);
+ StorageDead(_12);
goto -> bb10;
}
bb7: {
- StorageLive(_18);
- _41 = deref_copy (_4.1: &ViewportPercentageLength);
- _18 = (((*_41) as Vh).0: f32);
StorageLive(_17);
- _42 = deref_copy (_4.0: &ViewportPercentageLength);
- _17 = (((*_42) as Vh).0: f32);
+ _41 = deref_copy (_4.0: &ViewportPercentageLength);
+ _17 = (((*_41) as Vh).0: f32);
+ StorageLive(_18);
+ _42 = deref_copy (_4.1: &ViewportPercentageLength);
+ _18 = (((*_42) as Vh).0: f32);
StorageLive(_19);
StorageLive(_20);
_20 = _17;
@@ -154,18 +154,18 @@
StorageDead(_20);
_3 = ViewportPercentageLength::Vh(move _19);
StorageDead(_19);
- StorageDead(_17);
StorageDead(_18);
+ StorageDead(_17);
goto -> bb10;
}
bb8: {
- StorageLive(_23);
- _43 = deref_copy (_4.1: &ViewportPercentageLength);
- _23 = (((*_43) as Vmin).0: f32);
StorageLive(_22);
- _44 = deref_copy (_4.0: &ViewportPercentageLength);
- _22 = (((*_44) as Vmin).0: f32);
+ _43 = deref_copy (_4.0: &ViewportPercentageLength);
+ _22 = (((*_43) as Vmin).0: f32);
+ StorageLive(_23);
+ _44 = deref_copy (_4.1: &ViewportPercentageLength);
+ _23 = (((*_44) as Vmin).0: f32);
StorageLive(_24);
StorageLive(_25);
_25 = _22;
@@ -176,18 +176,18 @@
StorageDead(_25);
_3 = ViewportPercentageLength::Vmin(move _24);
StorageDead(_24);
- StorageDead(_22);
StorageDead(_23);
+ StorageDead(_22);
goto -> bb10;
}
bb9: {
- StorageLive(_28);
- _45 = deref_copy (_4.1: &ViewportPercentageLength);
- _28 = (((*_45) as Vmax).0: f32);
StorageLive(_27);
- _46 = deref_copy (_4.0: &ViewportPercentageLength);
- _27 = (((*_46) as Vmax).0: f32);
+ _45 = deref_copy (_4.0: &ViewportPercentageLength);
+ _27 = (((*_45) as Vmax).0: f32);
+ StorageLive(_28);
+ _46 = deref_copy (_4.1: &ViewportPercentageLength);
+ _28 = (((*_46) as Vmax).0: f32);
StorageLive(_29);
StorageLive(_30);
_30 = _27;
@@ -198,8 +198,8 @@
StorageDead(_30);
_3 = ViewportPercentageLength::Vmax(move _29);
StorageDead(_29);
- StorageDead(_27);
StorageDead(_28);
+ StorageDead(_27);
goto -> bb10;
}
diff --git a/tests/mir-opt/early_otherwise_branch_noopt.noopt1.EarlyOtherwiseBranch.diff b/tests/mir-opt/early_otherwise_branch_noopt.noopt1.EarlyOtherwiseBranch.diff
index d7908ab3cd2..7fdd8554e38 100644
--- a/tests/mir-opt/early_otherwise_branch_noopt.noopt1.EarlyOtherwiseBranch.diff
+++ b/tests/mir-opt/early_otherwise_branch_noopt.noopt1.EarlyOtherwiseBranch.diff
@@ -59,13 +59,13 @@
}
bb5: {
- StorageLive(_10);
- _10 = (((_3.1: std::option::Option<u32>) as Some).0: u32);
StorageLive(_9);
_9 = (((_3.0: std::option::Option<u32>) as Some).0: u32);
+ StorageLive(_10);
+ _10 = (((_3.1: std::option::Option<u32>) as Some).0: u32);
_0 = const 0_u32;
- StorageDead(_9);
StorageDead(_10);
+ StorageDead(_9);
goto -> bb8;
}
diff --git a/tests/mir-opt/exponential_or.match_tuple.SimplifyCfg-initial.after.mir b/tests/mir-opt/exponential_or.match_tuple.SimplifyCfg-initial.after.mir
index ea5cd55b560..596dcef85fd 100644
--- a/tests/mir-opt/exponential_or.match_tuple.SimplifyCfg-initial.after.mir
+++ b/tests/mir-opt/exponential_or.match_tuple.SimplifyCfg-initial.after.mir
@@ -19,8 +19,7 @@ fn match_tuple(_1: (u32, bool, Option<i32>, u32)) -> u32 {
bb0: {
PlaceMention(_1);
- _2 = discriminant((_1.2: std::option::Option<i32>));
- switchInt(move _2) -> [0: bb3, 1: bb2, otherwise: bb1];
+ switchInt((_1.0: u32)) -> [1: bb2, 4: bb2, otherwise: bb1];
}
bb1: {
@@ -29,11 +28,12 @@ fn match_tuple(_1: (u32, bool, Option<i32>, u32)) -> u32 {
}
bb2: {
- switchInt((((_1.2: std::option::Option<i32>) as Some).0: i32)) -> [1: bb3, 8: bb3, otherwise: bb1];
+ _2 = discriminant((_1.2: std::option::Option<i32>));
+ switchInt(move _2) -> [0: bb4, 1: bb3, otherwise: bb1];
}
bb3: {
- switchInt((_1.0: u32)) -> [1: bb4, 4: bb4, otherwise: bb1];
+ switchInt((((_1.2: std::option::Option<i32>) as Some).0: i32)) -> [1: bb4, 8: bb4, otherwise: bb1];
}
bb4: {
diff --git a/tests/ui/pattern/bindings-after-at/bind-by-copy-or-pat.rs b/tests/ui/pattern/bindings-after-at/bind-by-copy-or-pat.rs
new file mode 100644
index 00000000000..1555da2fd1f
--- /dev/null
+++ b/tests/ui/pattern/bindings-after-at/bind-by-copy-or-pat.rs
@@ -0,0 +1,17 @@
+//@ known-bug: unknown
+#![allow(unused)]
+
+struct A(u32);
+
+pub fn main() {
+ // The or-pattern bindings are lowered after `x`, which triggers the error.
+ let x @ (A(a) | A(a)) = A(10);
+ // ERROR: use of moved value
+ assert!(x.0 == 10);
+ assert!(a == 10);
+
+ // This works.
+ let (x @ A(a) | x @ A(a)) = A(10);
+ assert!(x.0 == 10);
+ assert!(a == 10);
+}
diff --git a/tests/ui/pattern/bindings-after-at/bind-by-copy-or-pat.stderr b/tests/ui/pattern/bindings-after-at/bind-by-copy-or-pat.stderr
new file mode 100644
index 00000000000..79808186358
--- /dev/null
+++ b/tests/ui/pattern/bindings-after-at/bind-by-copy-or-pat.stderr
@@ -0,0 +1,31 @@
+error[E0382]: use of moved value
+ --> $DIR/bind-by-copy-or-pat.rs:8:16
+ |
+LL | let x @ (A(a) | A(a)) = A(10);
+ | - ^ ----- move occurs because value has type `A`, which does not implement the `Copy` trait
+ | | |
+ | | value used here after move
+ | value moved here
+ |
+help: borrow this binding in the pattern to avoid moving the value
+ |
+LL | let ref x @ (A(a) | A(a)) = A(10);
+ | +++
+
+error[E0382]: use of moved value
+ --> $DIR/bind-by-copy-or-pat.rs:8:23
+ |
+LL | let x @ (A(a) | A(a)) = A(10);
+ | - ^ ----- move occurs because value has type `A`, which does not implement the `Copy` trait
+ | | |
+ | | value used here after move
+ | value moved here
+ |
+help: borrow this binding in the pattern to avoid moving the value
+ |
+LL | let ref x @ (A(a) | A(a)) = A(10);
+ | +++
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0382`.