<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/60545>60545</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Coroutine codegen confused by top-level const in size parameter of custom delete for promise
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            c++20,
            clang:frontend,
            coroutines
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          CaseyCarter
      </td>
    </tr>
</table>

<pre>
    Compiling this well-formed TU:
```c++
#include <coroutine>
#include <cstddef>

#ifdef WORKAROUND
#define CONST
#else
#define CONST const
#endif

struct generator {
    struct promise_type {
 generator get_return_object();
        std::suspend_always initial_suspend();
        std::suspend_always final_suspend() noexcept;
        void return_void();
        [[noreturn]] void unhandled_exception();

        static void* operator new(std::size_t size);
        static void operator delete(void* ptr, CONST std::size_t size); // Line 19
    };
};

void f() { delete new generator::promise_type; } // Fine
generator g() { co_return; } // Line 24
```
with `clang -std=c++2b -stdlib=libc++` produces diagnostics (https://godbolt.org/z/7arWY6M98):
```
<source>:24:11: error: too few arguments to function call, expected 2, have 1
generator g() { co_return; } // Line 24
          ^
<source>:19:21: note: 'operator delete' declared here
        static void operator delete(void* ptr, CONST std::size_t size); // Line 19
                    ^
1 error generated.
```
Defining `WORKAROUND` (so `CONST` becomes empty instead of `const`) makes the problem go away. It would appear that the coroutine frame deallocation machinery in the compiler is confused by the presence of top-level `const` on `operator delete`'s second (`size_t`) parameter.
</pre>
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