Put new bindings first in refutable cases too

Author: Nadrieril

compiler/rustc_mir_build/src/build/matches/simplify.rs

@@ -87,7 +87,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         //     let z = (x as Variant).copy_field;
         //     // and raises an error
         // }
-        let mut original_bindings = mem::take(&mut candidate.bindings);
+        let original_bindings = mem::take(&mut candidate.bindings);
         let mut new_bindings = Vec::new();
         // Repeatedly simplify match pairs until fixed point is reached
         loop {
@@ -115,9 +115,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         }
 
         // Restore original bindings and append the new ones.
-        // This does: candidate.bindings = original_bindings ++ new_bindings
-        mem::swap(&mut candidate.bindings, &mut original_bindings);
-        candidate.bindings.extend_from_slice(&new_bindings);
+        // This does: candidate.bindings = new_bindings ++ original_bindings
+        mem::swap(&mut candidate.bindings, &mut new_bindings);
+        candidate.bindings.extend_from_slice(&original_bindings);
 
         let did_expand_or =
             if let [MatchPair { pattern: Pat { kind: PatKind::Or { pats }, .. }, place }] =

tests/mir-opt/early_otherwise_branch.opt1.EarlyOtherwiseBranch.diff

@@ -51,13 +51,13 @@
 -     }
 - 
 -     bb3: {
-          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);
+          StorageLive(_8);
+          _8 = (((_3.0: std::option::Option<u32>) as Some).0: u32);
           _0 = const 0_u32;
-          StorageDead(_9);
           StorageDead(_8);
+          StorageDead(_9);
 -         goto -> bb4;
 +         goto -> bb3;
       }

tests/mir-opt/early_otherwise_branch.opt2.EarlyOtherwiseBranch.diff

@@ -58,13 +58,13 @@
 - 
 -     bb4: {
 +     bb2: {
-          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);
+          StorageLive(_9);
+          _9 = (((_3.0: std::option::Option<u32>) as Some).0: u32);
           _0 = const 0_u32;
-          StorageDead(_10);
           StorageDead(_9);
+          StorageDead(_10);
 -         goto -> bb6;
 +         goto -> bb4;
       }

tests/mir-opt/early_otherwise_branch.opt3.EarlyOtherwiseBranch.diff

@@ -51,13 +51,13 @@
 -     }
 - 
 -     bb3: {
-          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);
+          StorageLive(_8);
+          _8 = (((_3.0: std::option::Option<u32>) as Some).0: u32);
           _0 = const 0_u32;
-          StorageDead(_9);
           StorageDead(_8);
+          StorageDead(_9);
 -         goto -> bb4;
 +         goto -> bb3;
       }

tests/mir-opt/early_otherwise_branch_3_element_tuple.opt1.EarlyOtherwiseBranch.diff

@@ -69,16 +69,16 @@
 
 -     bb4: {
 +     bb3: {
-          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);
+          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);
           _0 = const 0_u32;
-          StorageDead(_13);
-          StorageDead(_12);
           StorageDead(_11);
+          StorageDead(_12);
+          StorageDead(_13);
 -         goto -> bb5;
 +         goto -> bb4;
       }

tests/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff

@@ -116,12 +116,12 @@
       }
 
       bb6: {
-          StorageLive(_12);
-          _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);
+          _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);
           StorageLive(_14);
           StorageLive(_15);
           _15 = _12;
@@ -132,18 +132,18 @@
           StorageDead(_15);
           _3 = ViewportPercentageLength::Vw(move _14);
           StorageDead(_14);
-          StorageDead(_13);
           StorageDead(_12);
+          StorageDead(_13);
           goto -> bb10;
       }
 
       bb7: {
-          StorageLive(_17);
-          _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);
+          _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);
           StorageLive(_19);
           StorageLive(_20);
           _20 = _17;
@@ -154,18 +154,18 @@
           StorageDead(_20);
           _3 = ViewportPercentageLength::Vh(move _19);
           StorageDead(_19);
-          StorageDead(_18);
           StorageDead(_17);
+          StorageDead(_18);
           goto -> bb10;
       }
 
       bb8: {
-          StorageLive(_22);
-          _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);
+          _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);
           StorageLive(_24);
           StorageLive(_25);
           _25 = _22;
@@ -176,18 +176,18 @@
           StorageDead(_25);
           _3 = ViewportPercentageLength::Vmin(move _24);
           StorageDead(_24);
-          StorageDead(_23);
           StorageDead(_22);
+          StorageDead(_23);
           goto -> bb10;
       }
 
       bb9: {
-          StorageLive(_27);
-          _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);
+          _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);
           StorageLive(_29);
           StorageLive(_30);
           _30 = _27;
@@ -198,8 +198,8 @@
           StorageDead(_30);
           _3 = ViewportPercentageLength::Vmax(move _29);
           StorageDead(_29);
-          StorageDead(_28);
           StorageDead(_27);
+          StorageDead(_28);
           goto -> bb10;
       }
 

tests/mir-opt/early_otherwise_branch_noopt.noopt1.EarlyOtherwiseBranch.diff

@@ -59,13 +59,13 @@
       }
 
       bb5: {
-          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);
+          StorageLive(_9);
+          _9 = (((_3.0: std::option::Option<u32>) as Some).0: u32);
           _0 = const 0_u32;
-          StorageDead(_10);
           StorageDead(_9);
+          StorageDead(_10);
           goto -> bb8;
       }
 

tests/ui/pattern/bindings-after-at/bind-by-copy.rs

@@ -1,3 +1,4 @@
+// run-pass
 #![allow(unused)]
 
 // Test copy
@@ -41,7 +42,6 @@ pub fn main() {
 
     match (E::E { a: 10, e: C { c: 20 } }) {
         x @ E::E{ a, e: C { c } } => {
-            //~^ ERROR use of moved value
             assert!(matches!(x, E::E { a: 10, e: C { c: 20 } }));
             assert!(a == 10);
             assert!(c == 20);
@@ -50,7 +50,6 @@ pub fn main() {
     }
     match (E::E { a: 10, e: C { c: 20 } }) {
         mut x @ E::E{ a, e: C { mut c } } => {
-            //~^ ERROR use of moved value
             x = E::NotE;
             c += 30;
             assert_eq!(c, 50);

tests/ui/pattern/bindings-after-at/borrowck-move-and-move.rs

@@ -15,8 +15,8 @@ fn main() {
     let a @ (b, c) = (u(), u()); //~ ERROR use of partially moved value
 
     match Ok(U) {
-        a @ Ok(b) | a @ Err(b) => {} //~ ERROR use of moved value
-                                     //~^ ERROR use of moved value
+        a @ Ok(b) | a @ Err(b) => {} //~ ERROR use of partially moved value
+                                     //~^ ERROR use of partially moved value
     }
 
     fn fun(a @ b: U) {} //~ ERROR use of moved value

tests/ui/pattern/bindings-after-at/borrowck-move-and-move.stderr

@@ -40,35 +40,33 @@ help: borrow this binding in the pattern to avoid moving the value
 LL |     let ref a @ (b, ref c) = (u(), u());
    |         +++         +++
 
-error[E0382]: use of moved value
-  --> $DIR/borrowck-move-and-move.rs:18:16
+error[E0382]: use of partially moved value
+  --> $DIR/borrowck-move-and-move.rs:18:9
    |
-LL |     match Ok(U) {
-   |           ----- move occurs because value has type `Result<U, U>`, which does not implement the `Copy` trait
 LL |         a @ Ok(b) | a @ Err(b) => {}
-   |         -      ^ value used here after move
+   |         ^      - value partially moved here
    |         |
-   |         value moved here
+   |         value used here after partial move
    |
+   = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
 help: borrow this binding in the pattern to avoid moving the value
    |
-LL |         ref a @ Ok(b) | a @ Err(b) => {}
-   |         +++
+LL |         ref a @ Ok(ref b) | a @ Err(b) => {}
+   |         +++        +++
 
-error[E0382]: use of moved value
-  --> $DIR/borrowck-move-and-move.rs:18:29
+error[E0382]: use of partially moved value
+  --> $DIR/borrowck-move-and-move.rs:18:21
    |
-LL |     match Ok(U) {
-   |           ----- move occurs because value has type `Result<U, U>`, which does not implement the `Copy` trait
 LL |         a @ Ok(b) | a @ Err(b) => {}
-   |                     -       ^ value used here after move
+   |                     ^       - value partially moved here
    |                     |
-   |                     value moved here
+   |                     value used here after partial move
    |
+   = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
 help: borrow this binding in the pattern to avoid moving the value
    |
-LL |         a @ Ok(b) | ref a @ Err(b) => {}
-   |                     +++
+LL |         a @ Ok(b) | ref a @ Err(ref b) => {}
+   |                     +++         +++
 
 error[E0382]: use of partially moved value
   --> $DIR/borrowck-move-and-move.rs:25:9

tests/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref-inverse.rs

@@ -48,33 +48,30 @@ fn main() {
         //~^ ERROR borrow of moved value
         //~| ERROR borrow of moved value
         //~| ERROR borrow of moved value
-        //~| ERROR use of moved value
+        //~| ERROR use of partially moved value
         None => {}
     }
     match Some([U, U]) {
         mut a @ Some([ref b, ref mut c]) => {}
         //~^ ERROR borrow of moved value
-        //~| ERROR borrow of moved value
         None => {}
     }
     match Some(u()) {
         a @ Some(ref b) => {}
         //~^ ERROR borrow of moved value
-        //~| ERROR borrow of moved value
         None => {}
     }
     match Some((u(), u())) {
         a @ Some((mut b @ ref mut c, d @ ref e)) => {}
         //~^ ERROR borrow of moved value
         //~| ERROR borrow of moved value
         //~| ERROR borrow of moved value
-        //~| ERROR use of moved value
+        //~| ERROR use of partially moved value
         None => {}
     }
     match Some([u(), u()]) {
         mut a @ Some([ref b, ref mut c]) => {}
         //~^ ERROR borrow of moved value
-        //~| ERROR borrow of moved value
         None => {}
     }
 }