[PATCH] D128619: [Clang] Implement P0848 (Conditionally Trivial Special Member Functions)

[Roy Jacobson via Phabricator via cfe-commits]

royjacobson added inline comments.


================
Comment at: clang/lib/Sema/SemaDecl.cpp:17875
+    return true;
+  if (!Context.hasSameType(M1->getParamDecl(0)->getType(),
+                           M2->getParamDecl(0)->getType()))
----------------
shafik wrote:
> What happens if we have further parameters with default arguments? Unless I am missing something they are still special member functions but the proposal does not seem to cover them.
That's an excellent question.

I'm not sure what to do about default arguments. In a context where the additional parameters matter, you're not using them as constructors anymore, right? So why would this affect the type traits?
On the one hand [over.match.best] is against this idea of comparing constraints when the parameters differ. So also every context where this actually matters the overload resolution would probably be ambiguous anyway?

@BRevzin, what do you think? Is the wording intentional to include copy/move constructors with default arguments as well?

I checked with GCC and they seem to handle default arguments separately: https://godbolt.org/z/1ch3M7MjP



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https://reviews.llvm.org/D128619