1 files changed, 3 insertions, 0 deletions
diff --git a/source/slang/slang-ir-lower-generics.cpp b/source/slang/slang-ir-lower-generics.cpp
index c95f6976c..6b8150605 100644
--- a/source/slang/slang-ir-lower-generics.cpp
+++ b/source/slang/slang-ir-lower-generics.cpp
@@ -55,6 +55,9 @@ namespace Slang
             switch (inst->getOp())
             {
             case kIROp_WitnessTableIDType:
+                if (isComInterfaceType((IRType*)inst->getOperand(0)))
+                    continue;
+                // fall through
             case kIROp_RTTIHandleType:
                 {
                     IRBuilder builder(sharedContext->sharedBuilderStorage);