Hi,

On 06/03/2018 21:33, Jason Merrill wrote:
> Interesting, that seems like a promising idea.  I'm not sure we need
> to do this based on an error in a default template arg, though; can we
> drop
>
> +  || error_operand_p (TREE_PURPOSE (parameter)))
>
> ?
Good point, yes, I believe we can, isn't necessary for all the snippets 
I have around neither apparently to pass the testsuite (but this is 
rather straightforward, right?). As I said, I tried many different 
things, some also fiddled with TREE_PURPOSE, in pt.c too, but in what I 
sent I only added the check out of a reflex. Anyway, the below is in 
libstdc++, so far so good.

Thanks,
Paolo.

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