Looking at the async test cases in https://github.com/dotnet/roslyn/blob/master/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenAsyncTests.cs, there does not appear to be any case in which an exception is thrown inside a try/finally block and not caught, causing the finally to be entered from exceptional control flow rather than ordinary control flow.

Note: The AnonType32 and Await43 tests do throw exceptions inside a try/finally block, but then they both catch them before entering finally.

Filing this as an issue per @jmarolf.