EffectAnalyzer: Do not clear break targets before walk()/visit() (#5723)

We depend on repeated calls to walk/visit accumulating effects, so this
was a bug; if we want to clear stuff then we create a new EffectAnalyzer.

Removing that fixes the attached testcase. Also added a unit test.

1 files changed, 0 insertions, 7 deletions

diff --git a/src/ir/effects.h b/src/ir/effects.h
index b4987b12b..833da2540 100644
--- a/src/ir/effects.h
+++ b/src/ir/effects.h
@@ -53,14 +53,12 @@ public:
 
   // Walk an expression and all its children.
   void walk(Expression* ast) {
-    pre();
     InternalAnalyzer(*this).walk(ast);
     post();
   }
 
   // Visit an expression, without any children.
   void visit(Expression* ast) {
-    pre();
     InternalAnalyzer(*this).visit(ast);
     post();
   }
@@ -1024,11 +1022,6 @@ public:
   }
 
 private:
-  void pre() {
-    breakTargets.clear();
-    delegateTargets.clear();
-  }
-
   void post() {
     assert(tryDepth == 0);