opDispatch compiles fine, but still fails to resolve?

[Vlad Levenfeld via Digitalmars-d-learn]

On Saturday, 9 August 2014 at 10:36:55 UTC, Artur Skawina via 
Digitalmars-d-learn wrote:
> On 08/09/14 03:20, Vlad Levenfeld via Digitalmars-d-learn wrote:
>> More opDispatch woes. This feature keeps biting me, yet I keep 
>> trying to use it.
>> 
>> This time I'm trying to access elements of a vector GLSL-style 
>> (without swizzling... for now).
>> 
>> Here's the relevant code:
>> 
>> struct Vector (uint length, Element = double)
>> {
>>         ref @property component (string c)()
>>         {
>>             enum mat = q{xyzw};
>>             enum col = q{rgba};
>>             enum tex = q{uv};
>> 
>>             static if (mat.canFind (c))
>>                 return components[mat.countUntil (c)];
>>             else static if (col.canFind (c))
>>                 return components[col.countUntil (c)];
>>             else static if (tex.canFind (c))
>>                 return components[tex.countUntil (c)];
>>             else static assert (0);
>>         }
>> 
>>         ref @property opDispatch (string c)()
>>         if (c.length == 1)
>>         {
>>             auto v = component!c;
>>             pragma(msg, typeof(v)); // this outputs the 
>> expected result
>>             return v; // so everything is fine, right? wrong...
>>         }
>> 
>>     Element[length] components;
>> }
>> 
>> Calling vector.component!`x` or something works fine, but 
>> calling vector.x fails with "Error: no property" etc.
>> 
>> Now, I'm used to opDispatch silently failing when it can't 
>> compile (very annoying btw), but in this case, I tested every 
>> line with a pragma (msg, __traits(compiles...)) and everything 
>> checks out. All expressions are verified CTFE-able. The 
>> compiler apparently makes it all the way through the method 
>> without a hitch, but then just fails symbol resolution anyway.
>> 
>> Is this just a bug? Does anyone have any advice on what else 
>> to try?
>
> v.opDispatch!`x`;
>
> Your opDispatch is returning a reference to a local 
> stack-allocated
> variable. D does not support real references; that 'auto v=...'
> declaration creates a copy.
>
>    ref @property opDispatch (string c)() { return component!c; }
>
> [opDispatch works for every kind of symbol, there's no problem 
> with
>  @property]
>
> artur

Yeah, sorry, I made that change last-minute to verify, with the 
pragma, that I was indeed getting the correct type. The problem 
must have been something else. I just made a complete oversight 
in the process of throwing everything but the kitchen sink into 
debugging it.