Struct hidden context pointers

[Jonathan M Davis]

On Saturday, July 06, 2013 14:13:29 H. S. Teoh wrote:
> Today, while trying to track down what I thought was a bug in GDC, I
> discovered the following, which looks suspiciously like a bug / quality
> of implementation issue:
> 
> 	import std.conv;
> 
> 	// Function to test if T is independently instantiable.
> 	void f(T)() {
> 	    T t;
> 	}
> 
> 	unittest {
> 	    struct S {
> 		int x;
> 	    }
> 	    struct T {
> 		int y;
> 		bool f() { return true; }
> 	    }
> 
> 	    f!S();	// works
> 	    f!T();	// test.d(4): Error: cannot access frame pointer of
> test.__unittestL7_1.T // test.d(17): Error: template instance test.f!(T)
> error instantiating
> 
> 	}
> 	void main() { }
> 
> 
> The thing is, nowhere in the definition of T is any frame pointer
> required; apparently the frame pointer is triggered by the existence of
> any methods in the struct.
> 
> Shouldn't the frame pointer be generated only if f() actually tries to
> access something outside of the definition of T?

Probably, but that's arguably an optimization. Regardless, marking it as 
static will force the issue.

- Jonathan M Davis