close #15563 add testcase (#17168)

* remove unnecessary when statement

* remove outdated codes

* close #15563

* Update tests/typerel/t15563.nim

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>

* address comments

* tiny

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>

tests/stdlib/tvarargs.nim

@@ -0,0 +1,18 @@
+discard """
+  targets: "c js"
+  matrix: "--gc:refc; --gc:arc"
+"""
+
+
+template main =
+  proc hello(x: varargs[string]): seq[string] =
+    var s: seq[string]
+    s.add x
+    s
+
+  doAssert hello() == @[]
+  doAssert hello("a1") == @["a1"]
+  doAssert hello("a1", "a2") == @["a1", "a2"]
+
+static: main()
+main()