Bad error message on const ref fields

Valid code:

static void Test(int x)
{
    ref int y = ref x;
}

Invalid code:

static void Test(int x)
{
    const ref int y = ref x;
}

Expected: an error message on const specifying that you cannot use ref and const modifiers together.

Found: parser fails with the following errors:

1. CS1525 Invalid expression term 'ref'
2. CS1002 ; expected
3. CS1001 Identifier expected
4. CS8172 Cannot initialize a by-reference variable with a value
5. CS0118 'x' is a variable but is used like a type
6. CS8174 A declaration of a by-reference variable must have an initializer