template returning delegate

[Marek Janukowicz]

Yet another problem I just spotted:

-----------------------

import std.stdio, std.string;

struct Val {
  int i;
  byte b;
} 

template templ( T ) {

   auto templ (T obj, string name) {
    foreach( s; __traits(derivedMembers, T)) {
      if (s == name) {
        static if( is(typeof(__traits(getAttributes, __traits(getMember, T, 
s))) blah)) { // Rule out "non-regular" members
          //return format( "%s", __traits(getMember, obj, s)); // Version A
          return cast(string delegate())() { return 
format("%s",__traits(getMember, obj, s)); }; // Version B
        }
      }
    }
    throw new Exception("Invalid member");
  }
}

void main (string [] args) {
  Val v = Val(1, 2);
  //writefln( "%s: %s", args[1], templ!()(v, args[1]));   // Version A
  writefln( "%s: %s", args[1], templ!()(v, args[1])()); // Version B
}

---------------------------

Now running:
$ dmd -run member.d i
/usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/../../../../x86_64-pc-linux-
gnu/bin/ld: Warning: size of symbol 
`_D6member23__T5templTS6member3ValZ5templFNfS6member3ValAyaZDFZAya9__lambda1MFZAya' 
changed from 32 in member.o to 33 in member.o
i: 1

$ dmd -run member.d b
/usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/../../../../x86_64-pc-linux-
gnu/bin/ld: Warning: size of symbol 
`_D6member23__T5templTS6member3ValZ5templFNfS6member3ValAyaZDFZAya9__lambda1MFZAya' 
changed from 32 in member.o to 33 in member.o
b: 1  # Why not 2?

If I compile using ldc2 I get exactly the same result, so the delegate 
returned from template always returns value of "i" member (maybe it's always 
the first member that is returned). Ld warning is not present then.

However if I comment "Version B" lines and uncomment "Version A" (which 
means I return the result directly instead of returning the delegate I get 
expected results:

$ dmd -run member.d i
i: 1

$ dmd -run member.d b
b: 2

Also no ld warning in this case.

-- 
Marek Janukowicz