Querying Enums containing string initializers with a variable throws TS7015

TypeScript Version: 2.4.2

Code

enum Colors {
  Red = 'RED',
  Green = 'GREEN',
  Blue = 'BLUE',
}
const test: string = 'Red';
Colors[test];

Workaround

enum Colors {
  Red = 'RED',
  Green = 'GREEN',
  Blue = 'BLUE',
}
const test: any = 'Red';
Colors[test];

Expected behavior: Should compile

Actual behavior:

error TS7015: Element implicitly has an ‘any’ type because index expression is not of type ‘number’.

There is an issue #11773 demonstrating it with a “normal” enum.

[fmpierce]

I found the fix!

const test: keyof typeof Colors = 'Red';

I had the same problem and that fixed it.

[RyanCavanaugh]

Seems we never did anything different with the indexing rules for string enums, which is bad. Colors[32] is extremely suspect.