On Tue, Feb 13, 2018 at 10:43 AM, Paolo Carlini
> On 13/02/2018 15:35, Jason Merrill wrote:
> Thanks. Unfortunately, I don't think I sent a complete solution for these
> issues. In fact we would still ICE on:
> template<typename T> int foo()
> return sizeof(T) > 1 ? : 1;
> because type_contains_placeholder_p doesn't know how to handle a
> TEMPLATE_TYPE_PARM. In fact, cp_save_expr teaches me something:
> cp_save_expr (tree expr)
> /* There is no reason to create a SAVE_EXPR within a template; if
> needed, we can create the SAVE_EXPR when instantiating the
> template. Furthermore, the middle-end cannot handle C++-specific
> tree codes. */
> if (processing_template_decl)
> return expr;
> return save_expr (expr);
> would it be correct to just use it? Or we have to do something more complex?
> Note the issue only affects the GNU-extension with omitted middle operand,
> thus I believe we have *some* leeway...
Hmm, yes, that should work. In a template we're just figuring out the
result type, at instantiation time we'll see the missing middle op
again and can do the right thing. OK.