https://issues.dlang.org/show_bug.cgi?id=13780

          Issue ID: 13780
           Summary: Empty ParameterIdentifierTuple for function literal
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P1
         Component: DMD
          Assignee: nobody@puremagic.com
          Reporter: monkeyworks12@hotmail.com

import std.stdio;
import std.traits;

void main()
{
    //Prints a blank line
    writeln(ParameterIdentifierTuple!((int n) => n));
}

--