https://issues.dlang.org/show_bug.cgi?id=23764

          Issue ID: 23764
           Summary: Message printed twice: Usage of in on parameter
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: regression
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: bugzilla@digitalmars.com

When switch:

  -transition=in

is used on:

  void main ()
  {
    void nested (in char c) {}
  }

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