1 files changed, 2 insertions, 0 deletions
diff --git a/source/slang/slang-ir-lower-generic-function.cpp b/source/slang/slang-ir-lower-generic-function.cpp
index 0f94f137d..806ea8826 100644
--- a/source/slang/slang-ir-lower-generic-function.cpp
+++ b/source/slang/slang-ir-lower-generic-function.cpp
@@ -268,6 +268,8 @@ namespace Slang
             IRInst* interfaceRequirementVal = nullptr;
             auto witnessTableType = as<IRWitnessTableType>(lookupInst->getWitnessTable()->getDataType());
             if (!witnessTableType) return;
+            if (witnessTableType->getConformanceType()->findDecoration<IRComInterfaceDecoration>())
+                return;
             auto interfaceType = maybeLowerInterfaceType(cast<IRInterfaceType>(witnessTableType->getConformanceType()));
             interfaceRequirementVal = sharedContext->findInterfaceRequirementVal(interfaceType, lookupInst->getRequirementKey());
             lookupInst->setFullType((IRType*)interfaceRequirementVal);