diff --git a/src/codegen.cpp b/src/codegen.cpp
index 79213c27b4..0c8613445c 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -537,7 +537,7 @@ static void gen_block(CodeGen *g, AstNode *block_node) {
             case NodeTypeFnCall:
             case NodeTypeExternBlock:
             case NodeTypeDirective:
-                assert(false);
+                zig_unreachable();
         }
     }