Ref returns/locals + Local Methods -- No error on "ref void" local methods

[dpoeschl]

Paste C# code:

class C
{
    void M()
    {
        ref void NoError() { }
    }

    ref void HasError() { } // CS 8898
}

Expected: The ref void local method NoError should be an error, probably with the same error code as the ref void member method HasError
Actual: The ref void local method has no errors, and compilation completes successfully

[dpoeschl]

/cc: @VSadov

[dpoeschl]

Also /cc: @balajikris

[dpoeschl]

The resultant assembly fails PEVerify. I didn't even dare run it. 😄

.method assembly hidebysig static void&  '<M>g__NoError0_0'() cil managed
{
  .custom instance void [mscorlib]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 ) 
  // Code size       2 (0x2)
  .maxstack  8
  IL_0000:  nop
  IL_0001:  ret
} // end of method C::'<M>g__NoError0_0'

[VSadov]

fixed in #8945