diff --git a/src/dawn/native/vulkan/external_memory/MemoryService.cpp b/src/dawn/native/vulkan/external_memory/MemoryService.cpp
index 0db58f4..02361e2 100644
--- a/src/dawn/native/vulkan/external_memory/MemoryService.cpp
+++ b/src/dawn/native/vulkan/external_memory/MemoryService.cpp
@@ -52,6 +52,7 @@
             // for prefersDA.
             return dedicatedRequirements.prefersDedicatedAllocation;
     }
+    DAWN_UNREACHABLE();
 }
 
 }  // namespace dawn::native::vulkan::external_memory