https://issues.dlang.org/show_bug.cgi?id=12641

          Issue ID: 12641
           Summary: D1: __FILE__ and __LINE__ default argument behaviour
           Product: D
           Version: D1
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: DMD
          Assignee: nobody@puremagic.com
          Reporter: public@dicebot.lv

```D
import std.stdio;

void foo(long line = __LINE__)
{
    writefln("{}", line);
}

void main()
{
    foo();
}
```

This code currently prints "10" with D2 compiler and "3" with D1 one. That forces to use lot of annoying boilerplate and is probably #1 feature to backport in terms of ROI.

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