permit global augmentations to introduce new names

[vladima]

fixes #8102

[DanielRosenwasser]

There's also a case for import = declarations above that reports this error in global module augmentations.

[vladima]

0f323ea also fixes asymmetry that we currently have: in ambient namespaces without explicitly exported declarations all entities were considered exported except imports. This is technically a breaking change in following scenario however I have no idea what this code might do in the first place

declare namespace A.B {
    let x: number;
}

declare namespace M {
    import X = A.B.x;
    let X: string;
}

M.X // refers to let X: string

It is only an issue in ambient case - non-ambient version correctly yields error about colliding declarations.

[mhegazy]

Can you run definitely typed tests on this change and see if there are any new errors? i have definitely seen this pattern in the past.

[vladima]

revering back since it breaks the following case:

declare module "A" {
    import X = A.B.C
    let y = X.M1;
}
declare module "A" {
    import X = A.B.C
    let z = X.M2;
}

[vladima]

@mhegazy any other comments?

[mhegazy]

👍