[PATCH] D87561: [Sema] List conversion validate character array

[Mark de Wever via Phabricator via cfe-commits]

Mordante added inline comments.


================
Comment at: clang/test/CXX/drs/dr14xx.cpp:411-414
+  void f(const char[4]);
+  void f(const wchar_t[4]);
+  void f(const char16_t[4]);
+  void f(const char32_t[4]);
----------------
rsmith wrote:
> These should presumably be references to arrays, rather than arrays, or the parameter type is as if you wrote (for example) `void f(const char *)`, which shouldn't get the special treatment here.
> 
> [over.ics.list]p4 mentions this in its footnote:
> 
> "Otherwise, if the parameter type is a character array [Footnote: Since there are no parameters of array type, this will only occur as the referenced type of a reference parameter.] and the initializer list has a single element that is an appropriately-typed string-literal (9.4.3), the implicit conversion sequence is the identity conversion."
Ah I missed that footnote. I reread the standard and can you confirm some cases?
```
namespace A { 
  void f(const char(&)[4]);
  void g() { f({"abc"}); }
}
namespace B { 
  void f(const char(&&)[4]);
  void g() { f({"abc"}); }
} 
```
both should work and with P0388 the array without bounds will also work.

I ask since this is my interpretation of the standard, but it seems there's a difference between implementations and `void f(const char(&&)[4]);` fails for "abc" but works for "ab".
It seems ICC and consider "abc" an lvalue in this case and not when using "ab".

Here's a gotbolt link with the examples https://godbolt.org/z/r1TKfx


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  https://reviews.llvm.org/D87561/new/

https://reviews.llvm.org/D87561