Permit using template strings for string literal types

[ericbf]

TypeScript Version: 3.2

Search Terms: NoSubstitutionTemplateLiteral, generic parameter, string type, string literal type

Code

const x: Promise<`hi`>

Expected behavior:

No error.

Actual behavior:

There are errors as it doesn't accept the string literal as a type param for the generic class.

Playground Link: link

Related Issues:
This idea was touched on by #17704, but this use case was missed.

[ericbf]

This seems to be working now. Dunno when it was fixed—marking this as done.