1 files changed, 4 insertions, 0 deletions
diff --git a/src/ir/effects.h b/src/ir/effects.h
index 0dd0902b1..393285924 100644
--- a/src/ir/effects.h
+++ b/src/ir/effects.h
@@ -747,6 +747,10 @@ private:
       parent.implicitTrap = true;
     }
     void visitStringEq(StringEq* curr) {}
+    void visitStringAs(StringAs* curr) {
+      // traps when ref is null.
+      parent.implicitTrap = true;
+    }
   };
 
 public: