Skip to content

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

Closed
@JsonFreeman

Description

@JsonFreeman

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;
}

Metadata

Metadata

Labels

Breaking ChangeWould introduce errors in existing codeBugA bug in TypeScriptFixedA PR has been merged for this issue

Type

No type

Projects

No projects

Relationships

None yet

Development

No branches or pull requests

Issue actions