How to stringify a template instantiation expression?

[Yuxuan Shui]

On Thursday, 1 March 2018 at 16:46:30 UTC, Yuxuan Shui wrote:
> On Wednesday, 28 February 2018 at 15:49:25 UTC, aliak wrote:
>> On Wednesday, 28 February 2018 at 15:09:56 UTC, Yuxuan Shui 
>> wrote:
>>> For a template instantiation expression like A!(B, C!(D, E)), 
>>> I want to get a string "A!(B, C!(D, E))", better if A, B, C, 
>>> D, E is replaced by fully qualified name.
>>>
>>> Is this possible?
>>
>> A!(B, C!(D, E)).stringof I guess. Will print the former.
>>
>> There's a Learn forum as well btw :)
>>
>> Cheers
>
> Did you actually try that? With dmd 2.079-rc1, this:
>
> template A(T...) {}
> struct B {}
> struct D {}
> struct E {}
> template C(T...) {}
> pragma(msg, (A!(B, C!(D, E))).stringof);
>
> Prints:
>
> A!(B, __T1CTS2ax1DTSQh1EZ)
>
> When compiled

Even worse, if the template instantiation yields another 
template, e.g:

template A(T) { template A(T) {} }

A!int.stringof returns "A(T)", which is not useful at all.