https://issues.dlang.org/show_bug.cgi?id=19555

          Issue ID: 19555
           Summary: Trait to get source location for symbol
           Product: D
           Version: D2
          Hardware: x86
                OS: Windows
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: simen.kjaras@gmail.com

Occasionally, one wants to print an error message regarding a symbol that is not defined in one's own code. An example would be a function that requires its parameter types have a certain @attribute:

struct Foo {}

void fun(T)(T t) {
    import std.traits : hasUDA;
    static if (!hasUDA!(T, "a")) {
        pragma(msg, "Type "~T.stringof~" does not have necessary @attribute");
    }
}

unittest {
    fun(Foo());
}

In this case, the best thing the pragma(msg) can do is print the line on which fun was invoked, but the actual issue is on the line where Foo is defined, and it would be beneficial if the error message actually stated this.

The exact issue that prompted this suggestion is issue 19554, which does essentially what's happening above - a confusing error message is created because it refers to a problem that is actually in a different location from where its effects occur.

--