This code compiles:
----
template gc_free(T) {
	static if (is(T : U*, U) || is(T : U[], U))
		alias Type = T;
	else
		alias Type = T*;

	void gc_free(Type data) {
		import core.memory : GC;

		static if (is(Type : U[], U)) {
			GC.free(data.ptr);
			GC.minimize();
		} else {
			GC.free(data);
		}

		data = null;
	}
}
----

But with a template condition it triggers compiler errors:
----
template gc_free(T) if (!is(T == class)) {
	static if (is(T : U*, U) || is(T : U[], U))
		alias Type = T;
	else
		alias Type = T*;

	void gc_free(Type data) {
		import core.memory : GC;

		static if (is(Type : U[], U)) {
			GC.free(data.ptr);
			GC.minimize();
		} else {
			GC.free(data);
		}

		data = null;
	}
}
----

Errors:
share.d(10): Error: undefined identifier Type
share.d(10): Error: undefined identifier Type
share.d(177): Error: template instance share.share!(A) error instantiating
share.d(10): Error: undefined identifier Type
share.d(10): Error: undefined identifier Type
share.d(197): Error: template instance share.share!(A) error instantiating
share.d(10): Error: undefined identifier Type
share.d(10): Error: undefined identifier Type
share.d(10): Error: undefined identifier Type
share.d(10): Error: undefined identifier Type
share.d(10): Error: undefined identifier Type
share.d(10): Error: undefined identifier Type

It seems to work on Linux with 64 bit, but it fails on Windows 7 32 bit.

Bug, feature or my fault?

On Sunday, 1 December 2013 at 16:07:18 UTC, Namespace wrote:
> This code compiles:
> ----
> template gc_free(T) {
> 	static if (is(T : U*, U) || is(T : U[], U))
> 		alias Type = T;
> 	else
> 		alias Type = T*;
>
> 	void gc_free(Type data) {
> 		import core.memory : GC;
>
> 		static if (is(Type : U[], U)) {
> 			GC.free(data.ptr);
> 			GC.minimize();
> 		} else {
> 			GC.free(data);
> 		}
>
> 		data = null;
> 	}
> }
> ----
>
> But with a template condition it triggers compiler errors:
> ----
> template gc_free(T) if (!is(T == class)) {
> 	static if (is(T : U*, U) || is(T : U[], U))
> 		alias Type = T;
> 	else
> 		alias Type = T*;
>
> 	void gc_free(Type data) {
> 		import core.memory : GC;
>
> 		static if (is(Type : U[], U)) {
> 			GC.free(data.ptr);
> 			GC.minimize();
> 		} else {
> 			GC.free(data);
> 		}
>
> 		data = null;
> 	}
> }
> ----
>
> Errors:
> share.d(10): Error: undefined identifier Type
> share.d(10): Error: undefined identifier Type
> share.d(177): Error: template instance share.share!(A) error instantiating
> share.d(10): Error: undefined identifier Type
> share.d(10): Error: undefined identifier Type
> share.d(197): Error: template instance share.share!(A) error instantiating
> share.d(10): Error: undefined identifier Type
> share.d(10): Error: undefined identifier Type
> share.d(10): Error: undefined identifier Type
> share.d(10): Error: undefined identifier Type
> share.d(10): Error: undefined identifier Type
> share.d(10): Error: undefined identifier Type
>
> It seems to work on Linux with 64 bit, but it fails on Windows 7 32 bit.
>
> Bug, feature or my fault?

Compiler bug.

https://d.puremagic.com/issues/show_bug.cgi?id=11662

Kenji Hara