Bug 13494 – Allow setting delegate member variables to do-nothing stub

There should be a way to set the default value of a delegate member variable to point to a do-nothing stub delegate that simply does nothing: ----- struct S { void delegate(dchar) dg = (dchar) {}; } ----- Currently there is no way to do this, because (1) the compiler doesn't know that the context pointer is actually unused and therefore can be set to null; (2) the compiler appears to be unable to generate code for S.init because it requires resolving the link-time address of the do-nothing delegate's body at compile-time. Both problems are solvable ((1): data flow analysis ought to reveal independence from context-pointer; (2): relocation entries should be generated where the .init value is used, so that the linker can fill in the address of the stub delegate).

*** This issue has been marked as a duplicate of issue 20498 ***