Rust: Abnormal completion in scrutinee does not continue to match arms

Author: paldepind

rust/ql/lib/codeql/rust/controlflow/internal/ControlFlowGraphImpl.qll

@@ -504,7 +504,8 @@ class MatchExprTree extends PostOrderTree instanceof MatchExpr {
   override predicate succ(AstNode pred, AstNode succ, Completion c) {
     // Edge from the scrutinee to the first arm.
     last(super.getExpr(), pred, c) and
-    first(super.getArm(0).getPat(), succ)
+    first(super.getArm(0).getPat(), succ) and
+    completionIsNormal(c)
     or
     // Edge from a failed match/guard in one arm to the beginning of the next arm.
     exists(int i |

rust/ql/test/library-tests/controlflow/Cfg.expected

@@ -595,7 +595,6 @@ edges
 | test.rs:276:34:276:40 | CallExpr | test.rs:276:19:276:40 | ... == ... |  |
 | test.rs:276:39:276:39 | 3 | test.rs:276:34:276:40 | CallExpr |  |
 | test.rs:277:13:277:20 | ReturnExpr | test.rs:275:5:284:5 | exit test_match_with_return_in_scrutinee (normal) | return |
-| test.rs:277:13:277:20 | ReturnExpr | test.rs:281:13:281:27 | TupleStructPat | return |
 | test.rs:277:13:277:21 | ExprStmt | test.rs:277:20:277:20 | 3 |  |
 | test.rs:277:20:277:20 | 3 | test.rs:277:13:277:20 | ReturnExpr |  |
 | test.rs:278:16:280:9 | BlockExpr | test.rs:276:16:280:9 | IfExpr |  |