fixes #4756 (#5557)

tests/errmsgs/t4756.nim

@@ -0,0 +1,16 @@
+discard """
+errormsg: "type mismatch: got (string, arr: seq[empty])"
+line: 15
+"""
+
+# https://github.com/nim-lang/Nim/issues/4756
+
+type
+  Test* = ref object
+    name*: string
+
+proc newTest(name: string, arr: seq): Test =
+    result = Test(name: name)
+
+let test = newTest("test", arr = @[])
+