std.traits functions causing the compiler to crash

[Regan Heath]

On Sat, 08 Jun 2013 05:52:49 +0100, Eric <eric at makechip.com> wrote:

> On Saturday, 8 June 2013 at 02:32:57 UTC, bearophile wrote:
>> Eric:
>>
>>> Yes, the template constraint is much better.  However, the compiler  
>>> still crashes, even with the new code:
>>
>> Because there's a type definition loop, regardless. Using a constraint  
>> doesn't change that situation.
>>
>> Bye,
>> bearophile
>
> How is there a type definition loop?  I'm just trying to constrain
> the interface.  At a minimum this should be a compiler bug, but
> I would hope that dimple constraints would work.

There is a type loop but I agree the compiler should really be able to  
catch it.

Using bearophile's short example..

import std.traits: hasMember;
interface Xidentity(V, K) if (!hasMember!(V, "x")) {
}
class Foo(K): Xidentity!(Foo!K, K) {
     K x;
}
void main() {
     new Foo!double;
}

The compiler starts by generating the template for Foo(double), requiring  
Xidentity(Foo!double,.. requiring Foo(double), requiring  
Xidentity(Foo!double,.., and so on..

It should really be able to detect that it is re-generating the original  
Foo(double) and simply re-use/terminate the loop there, I think. (I am no  
compiler expert however)

R

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