class C extends CBase<string> {
    constructor() {
        // Does not work
        super({
            method(p) { p.length; } // Error
        });
        // Works
        super.foo({
            method(p) { p.length; }
        });
    }
}
class CBase<T>  {
    constructor(param: ContextualType<T>) { } // Works if you change this to ContextualType<string>
    foo(param: ContextualType<T>) { }
}
interface ContextualType<T2> {
    method(parameter: T2): void;
}