[clang] [coroutines] Introduce [[clang::coro_return_type]] and [[clang::coro_wrapper]] (PR #71945)

[Utkarsh Saxena via cfe-commits]

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@@ -11591,6 +11591,10 @@ def err_conflicting_aligned_options : Error <
 def err_coro_invalid_addr_of_label : Error<
   "the GNU address of label extension is not allowed in coroutines."
 >;
+def err_coroutine_return_type : Error<
+  "function returns a coroutine return type %0 but is neither a coroutine nor a coroutine wrapper; "
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usx95 wrote:

Added [[clang::coro_return_type]] to the error message.

https://github.com/llvm/llvm-project/pull/71945