constructor instead of opCall for an instance of a template alias

[comco]

I have the following snippet:

struct A(alias Method)
{
    string s;
    this(Method method) {
        method(s); // 5
    }
}
struct B
{
    this(int i) { }
    void opCall(string s) { }
}


void main() {
    A!B(B(0));
}


This code fails to compile with the following errors:
test.d(5): Error: constructor test.B.this (int i) is not callable 
using argument types (string)
test.d(5): Error: cannot implicitly convert expression (this.s) 
of type string to int
test.d(17): Error: template instance test.A!(B) error 
instantiating
shell returned 1

It looks like the compiler is confusing the `method` instance 
parameter with the `Method` class.
If I replace line 5 with `method.opCall(s);` it compiles.

Can you explain this behaviour please?