[PATCH] D93630: [Attr] Apply GNU-style attributes to expression statements

[Valeriy Savchenko via Phabricator via cfe-commits]

vsavchenko added a comment.

@aaron.ballman I totally agree, but I also would like to understand. 
`__attribute__` is a GNU extension, right?  Then why does it affect the grammar of C?  I always thought that attributes should be somewhat transparent for parsers, but it looks like in this situation all compilers automatically assume that `__attribute__` begins a declaration.
It is unclear to me why `*x;`, `[[unknown]] *x;` (dereference of x) and `__attribute__((unknown)) *x;` (declaration of `int *`) have different meanings.

Does it essentially mean that there is no way to implement statement attributes in C/Obj-C?
Because even if we introduce some heuristics for understanding that what we parsed is a declaration attribute -> what follows must be a declaration, attributes that can be applied to both declaration and statements will cause confusion.


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  https://reviews.llvm.org/D93630/new/

https://reviews.llvm.org/D93630