Fix expansion of or-patterns

Author: Nadrieril

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

@@ -1411,6 +1411,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     break;
                 }
             }
+            if expand_until != 0 {
+                expand_until = i + 1;
+            }
         }
         let (candidates_to_expand, remaining_candidates) = candidates.split_at_mut(expand_until);
 

tests/mir-opt/building/match/simple_match.match_enum.built.after.mir

@@ -4,12 +4,11 @@ fn match_enum(_1: E1) -> bool {
     debug x => _1;
     let mut _0: bool;
     let mut _2: isize;
-    let mut _3: isize;
 
     bb0: {
         PlaceMention(_1);
         _2 = discriminant(_1);
-        switchInt(move _2) -> [0: bb3, 1: bb5, otherwise: bb2];
+        switchInt(move _2) -> [0: bb3, 1: bb5, 2: bb7, otherwise: bb2];
     }
 
     bb1: {
@@ -18,37 +17,36 @@ fn match_enum(_1: E1) -> bool {
     }
 
     bb2: {
-        _3 = discriminant(_1);
-        switchInt(move _3) -> [2: bb8, otherwise: bb1];
+        goto -> bb1;
     }
 
     bb3: {
-        goto -> bb7;
+        goto -> bb9;
     }
 
     bb4: {
         goto -> bb2;
     }
 
     bb5: {
-        goto -> bb7;
+        goto -> bb9;
     }
 
     bb6: {
         goto -> bb2;
     }
 
     bb7: {
-        falseEdge -> [real: bb10, imaginary: bb2];
+        _0 = const false;
+        goto -> bb11;
     }
 
     bb8: {
-        _0 = const false;
-        goto -> bb11;
+        goto -> bb2;
     }
 
     bb9: {
-        goto -> bb1;
+        falseEdge -> [real: bb10, imaginary: bb7];
     }
 
     bb10: {