7.2.5 Deviations from grammar ambiguities

> If a sequence of tokens can be parsed (in context) as a _simple-name_ (§12.7.3), _member-access_ (§12.7.5), or _pointer-member-access_ (§23.6.3) ending with a _type-argument-list_ (§9.4.2), the token immediately following the closing `>` token is examined. If it is one of
>         `( ) ] : ; , . ? == !=`
> then the _type-argument-list_ is retained as part of the _simple-name_, _member-access_, or _pointer-member-access_ and any other possible parse of the sequence of tokens is discarded. Otherwise, the _type-argument-list_ is not considered part of the _simple-name_, _member-access_, or _pointer-member-access_, even if there is no other possible parse of the sequence of tokens.

In practice, both Roslyn and Mono successfully parse:

``` C#
using System;

class C
{
public static bool operator ^(Action a, C b)
{
return true;
}

void Foo()
{
var x = Foo ^ this;
}
}
```

and

``` C#
using System;

class C
{
public static bool operator |(Action a, C b)
{
return true;
}

void Foo()
{
var x = Foo | this;
}
}
```

Mono also allows other operators (although Roslyn rejects them):

``` C#
using System;

class C
{
public static bool operator +(Action a, C b)
{
return true;
}

void Foo()
{
var x = Foo + this;
}
}
```

Should we update the spec, or just leave these as implementation quirks?