fixes #5404

tests/ccgbugs/tmangle_field.nim

@@ -0,0 +1,16 @@
+discard """
+"""
+
+# bug #5404
+
+import parseopt2
+
+{.emit: """typedef struct {
+    int key;
+} foo;""".}
+
+type foo* {.importc: "foo", nodecl.} = object
+  key* {.importc: "key".}: cint
+
+for kind, key, value in parseopt2.getopt():
+  discard