await in a static dynamic call materializes the call site's typeof marker as the receiver

[christophwille]

When a dynamic argument list containing an await is passed to a static method, the call site's typeof(TargetType) marker is materialized as a receiver variable, and the static call is rewritten as an instance call on that Type.

Input

public async Task DynamicAwaitInStaticCall(dynamic value)
{
	Console.WriteLine("x" + await value);
}

Actual output

public async Task DynamicAwaitInStaticCall(dynamic value)
{
	Type typeFromHandle = typeof(Console);
	typeFromHandle.WriteLine("x" + await value);
}

This is CS1061 (Type has no WriteLine).

Expected output

public async Task DynamicAwaitInStaticCall(dynamic value)
{
	Console.WriteLine("x" + await value);
}

Notes

The await is what triggers it. Both of these round-trip correctly:

• the same call without the await (Console.WriteLine("x" + value))
• the same await in a dynamic instance call

For a static dynamic call, Roslyn passes typeof(Console) to the call site as the target-type marker. Without a suspension point that ldtoken/GetTypeFromHandle pair stays inline and is recognized; the state-machine split hoists it into its own local first, and the dynamic-call transform then treats the local as an ordinary receiver.

[dgrunwald]

This likely has the same root cause as #4019.

[siegfriedpammer]

Duplicate of #3704; fixed by 8ab3f93