1 files changed, 26 insertions, 3 deletions
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index 90120233d..436eedb2b 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -1023,16 +1023,39 @@ void RefTest::finalize() {
   }
 }
 
+// Helper to get the cast type for a cast instruction. They all look at the rtt
+// operand's type.
+template<typename T> static Type doGetCastType(T* curr) {
+  if (curr->rtt->type == Type::unreachable) {
+    // We don't have the RTT type, so just return unreachable. The type in this
+    // case should not matter in practice, but it may be seen while debugging.
+    return Type::unreachable;
+  }
+  // TODO: make non-nullable when we support that
+  return Type(curr->rtt->type.getHeapType(), Nullable);
+}
+
+Type RefTest::getCastType() { return doGetCastType(this); }
+
 void RefCast::finalize() {
   if (ref->type == Type::unreachable || rtt->type == Type::unreachable) {
     type = Type::unreachable;
   } else {
-    // TODO: make non-nullable when we support that
-    type = Type(rtt->type.getHeapType(), Nullable);
+    type = getCastType();
+  }
+}
+
+Type RefCast::getCastType() { return doGetCastType(this); }
+
+void BrOnCast::finalize() {
+  if (ref->type == Type::unreachable || rtt->type == Type::unreachable) {
+    type = Type::unreachable;
+  } else {
+    type = ref->type;
   }
 }
 
-// TODO (gc): br_on_cast
+Type BrOnCast::getCastType() { return castType; }
 
 void RttCanon::finalize() {
   // Nothing to do - the type must have been set already during construction.