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

[Ilya Biryukov via cfe-commits]

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@@ -0,0 +1,99 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin9 %s -std=c++20 -fsyntax-only -verify -Wall -Wextra
+#include "Inputs/std-coroutine.h"
+
+using std::suspend_always;
+using std::suspend_never;
+
+
+template <typename T> struct [[clang::coro_return_type]] Gen {
+  struct promise_type {
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ilya-biryukov wrote:

We should also add a test with a type that's called differently.

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