target typing vs (expr), checked(expr), and unchecked(expr)

The language spec does not explain the apparent interaction of parenthesized expressions with target typing. For example, in the code

``` c#
var add = (Func)((x, y) => x + y);
```

The code should, by a pedantic reading of the spec, be an error because the lambda expression is not subject to a conversion. Rather, its enclosing parenthesized expression is subject to a conversion.