Conflict test case found for type definition.

[TotooriaHyperion]

I'm trying to improve BindingToSyntax type definition because it lost type check for toConstructor, toFactory to be compatible with type inferred from bind(XXX) ...etc

But I found conflict test cases:

Expected Behavior

types between BindingToSyntax should be compatible with generic type param of toConstructor.

Current Behavior

The right bottom example of BindingToSyntax<T> requires toConstructor(constructor: Newable<T>)
But the rest 3 examples of BindingToSyntax<Newable<T>> requires toConstructor(constructor: Newable<T>)

Possible Solution

This gives the toConstructor ability to infer the type from BindingToSyntax<T> if T is Newable or returns type never

But the Ninja test fails because it's using wrong types.

I need to change the test case of toConstructor<Ninja>(Ninja).

Steps to Reproduce (for bugs)

Context

Your Environment

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• Environment name and version (e.g. Chrome 39, node.js 5.4):
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Stack trace

[notaphplover]

Hey @TotooriaHyperion, I see, your proposal makes a lot of sense, but typescript is a bit tricky. I think there's an edge case we should try to cover:

Consider the following code example:

import { interfaces, LazyServiceIdentifer } from 'inversify';

type ExtendsLazyServiceIdentifier =
  LazyServiceIdentifer extends interfaces.Newable<LazyServiceIdentifer>
    ? true
    : false;

What type do you think is ExtendsLazyServiceIdentifier? The answer is, surprisingly false.

tsc declared types are not inferred as extending new (...args: any[]) => infer T, which is shocking.

I think I'll go to the tsc repo and ask why T is a new (...args: any[]) => infer T but only extends new (...args: any[]) => infer T when the class is not declared by tsc. Until that we will need to find a better solution.

EDIT: It seems https://stackoverflow.com/a/53056911 explains this weird behavior, I was not aware of this static-instance type duality of classes.

[notaphplover]

What about:

public toConstructor<T2 extends T>(
    constructor: interfaces.Newable<T2>,
  ): interfaces.BindingWhenOnSyntax<T>;

I think it would work nicely that way