1 files changed, 3 insertions, 0 deletions
diff --git a/src/wasm-validator.h b/src/wasm-validator.h
index 00a35fb24..29787a510 100644
--- a/src/wasm-validator.h
+++ b/src/wasm-validator.h
@@ -142,6 +142,9 @@ public:
         }
       }
     }
+    if (isConcreteWasmType(curr->type)) {
+      shouldBeTrue(curr->list.size() > 0, curr, "block with a value must not be empty");
+    }
   }
 
   static void visitPreLoop(WasmValidator* self, Expression** currp) {