Passing anonymous templated functions as template parameters

[pineapple via Digitalmars-d-learn]

Here's a simple code example to illustrate what I expected to 
work and didn't - is this a mistake in my syntax or a limitation 
of the language?

    template SomeTemplate(alias func){
        auto templatefunc(T)(int x){
            return func!T(x);
        }
    }
    // Valid
    auto somefunc(T)(int x){
        return cast(T) x;
    }
    alias fn1 = SomeTemplate!somefunc;

    // Not valid
    alias fn2 = SomeTemplate!(
        (T)(int x){return cast(T) x;}
    );