Can't autocomplete list of strings when union string | string is present

[usernamehw]

TypeScript Version: 3.2.1-dev.20181127

Search Terms:

Tried Domain: Completion Lists github label, didn't find a duplicate, there is probably one somewhere...

Code

type ListOrString = 'one' | 'two' | string;
const str: ListOrString = '';// Trigger autocomplete

Expected behavior:

Autocomplete shows

• one
• two

Actual behavior:

Only word suggestions.

[jack-williams]

Duplicate of #12687

The union type is simplified into a normal-form via subtype reduction; hovering over ListOrString will only show the supertype string.

[usernamehw]

So...

• it was working at some point
• it was reported and accepted to be a bug
• it was given an explanation new is always better

The type "foo" | "bar" | string is equivalent to the string type and now gets simplified early on. So all we see when querying the type checker for the type of x is string. So, this can't be fixed.

• the issue got closed and locked so nobody could find it

[weswigham]

I've tagged the old issue with a domain label for future use, but it predates when we used domain labels, which is why we didn't have one on it. And most old issues without activity are closed/locked.

[usernamehw]

Can this be implemented as a TS plugin then?

• Type checking should stay as it is
• Editor autocomplete should have these items

[weswigham]

We don't really have plugins - sans editor-wide ls plugins that wrap the entire ls. They can do anything, since they just wrap and intercept the LS, it's just not always easy.

[typescript-bot]

This issue has been marked as a duplicate and has seen no activity in the last day. It has been closed automatic house-keeping purposes.