fixes #23295; don't expand constants for complex structures (#23297)

fixes #23295

tests/objvariant/tconstobjvariant.nim

@@ -0,0 +1,18 @@
+# This is a sample code, the first echo statement prints out the error
+type
+  A = object
+    case w: uint8
+    of 1:
+      n: int
+    else:
+      other: string
+
+const
+  a = A(w: 1, n: 5)
+
+proc foo =
+
+  let c = [a]
+  doAssert c[0].n == 5
+
+foo()