fixes #4537

tests/converter/tor_in_converter.nim

@@ -0,0 +1,23 @@
+discard """
+  output: '''test
+test'''
+"""
+# bug #4537
+
+# nim js --d:nodejs
+
+type
+  Str = distinct string
+
+when true:
+  # crashes
+  converter convert(s: string | cstring): Str = Str($s)
+else:
+  # works!
+  converter convert(s: string): Str = Str($s)
+  converter convert(s: cstring): Str = Str($s)
+
+proc echoStr(s: Str) = echo s.string
+
+echoStr("test")
+echoStr("test".cstring)