Fix declaration emit for imported export alias specifiers

[weswigham]

Fixes #19825
Fixes #8612
Fixes #5938

This was actually broken waaaaaay back in TS 1.6 by #3641; the real underlying issue which prompted that change has since been fixed by other changes, so all this line did was break things. 😄

[mhegazy]

@weswigham does this address #8612 as well?

[weswigham]

@mhegazy Yes. Yes it does. Added repro.

[mhegazy]

and #5938 probably

[weswigham]

Yup. We've had this bug for a long time, haven't we?

[mhegazy]

yes we did.

[mhegazy]

i guess i am to blame for that one 😊

[loucyx]

Great work guys! Thanks!

[jacobbogers]

Great, if i install tsc in the project, not globally, the newest it will compile; but vscode editor still marks it as an error, maybe unrelated but its not picking up the new tsc? (globally de-installed tsc, so its only using the tsc of the project, me thinks)

[weswigham]

vscode has a copy of TS bundled with it. There's a workspace setting you can use to tell it to use the workspace certain instead.

[mhegazy]

Please see Using Newer TypeScript Versions documentation for more details on updating your VSCode to use a different version of TypeScript.

[jamiewinder]

I was hoping this was meant to fix a long-time bugbear of mine; I cannot using declarations with modules that export styled-component components.

For example, this very basic, very common scenario:

import styled from "styled-components";

export const Test = styled.div`
    color: black;
`;

i.e. just exporting a styled component, won't work because:

[ts] Exported variable 'Test' has or is using name 'React.ClassAttributes' from external module "node_modules/@types/react/index" but cannot be named.
[ts] Exported variable 'Test' has or is using name 'React.HTMLAttributes' from external module "node_modules/@types/react/index" but cannot be named.
[ts] Exported variable 'Test' has or is using name 'StyledComponentClass' from external module "node_modules/styled-components/typings/styled-components" but cannot be named.

Was this meant to fix this scenario? Because with 2.7.0-dev.20180103 I still get the same.

[weswigham]

No, that'd be related to #9944. For now you should be adding imports/references to the files whose types you need to use in your own declaration output, for now. For example,

import {StyledComponentClass}, styled from "styled-components";
import * as React from "react";

export const Test = styled.div`
    color: black;
`;

[jamiewinder]

OK, thanks. Unfortunately that approach doesn't work with --noUnusedLocals as you have to refer to the import at least once to suppress the warning (which can force in somewhere, but it's messy).

Thanks for clarifying.