Contextual type does not flow into a super call if it is based on a type argument to the base class

If you extend a generic class and pass a type argument, the instantiated constructor of the base class fails to contextually type the argument of a super call. This works correctly for base class methods, and it works correctly for constructors if the contextual type is not based on a type argument that was passed in the extends clause.

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;
}

Possibly related to #1424

Seems possibly related to #1480.

I think this should be fixed in #1816.

Also, is this really a breaking change?

Yeah it is a breaking change in 1.1 because the old compiler did not have this bug.

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Contextual type does not flow into a super call if it is based on a type argument to the base class #1425

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Contextual type does not flow into a super call if it is based on a type argument to the base class #1425

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JsonFreeman commented on Dec 10, 2014

DanielRosenwasser commented on Jan 21, 2015

DanielRosenwasser commented on Jan 28, 2015

DanielRosenwasser commented on Jan 28, 2015

JsonFreeman commented on Jan 28, 2015

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