Suggestion: const enums should be composable at compile time

[axefrog]

TypeScript Version: 2.5.2

I've found myself using const enums with (figuratively) namespaced property names. There is a lot of duplication when nesting though, and I keep finding myself wishing that the TypeScript compiler could recognise that its compile-time-constant requirement for such values was in fact satisfiable with respect to expressions composed of identifiers that are entirely compile-time resolvable.

Code

const enum Root {
  foo = 'foo';
}

const enum Nested {
  bar = Root.foo + ':bar',
  baz = `${A.foo}:baz`
}

// const strings could be included:

const root = 'root';
const enum Root {
  foo = root + ':foo';
}

// or another idea:

const enum Nested extends Root.foo {
  bar = ':bar' // => 'root:foo:bar'
}

I'm not sure how straightforward this would be to implement, but it does seem to me that if an expression can be resolved at compile time, it should be valid in a const enum type. If the compiler is able to resolve compile-time expressions at all, I imagine that some of the same code might also overlap with other issues relating to use of const symbols in interfaces.

[RyanCavanaugh]

Duplicate #13969 ?

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.