Inline const enum in import equals declaration

[jablko]

// @filename import-equals-const-enum.ts
const enum E { M }
const x1 = E.M;
import y1 = E.M;
const x2 = y1;

Currently we elide the enum declaration but not the import equals, which is an unavoidable reference error:

Base

// @filename import-equals-const-enum.js
var x1 = 0 /* M */;
var y1 = E.M;
var x2 = y1;

Head

// @filename import-equals-const-enum.js
var x1 = 0 /* M */;
var y1 = 0 /* M */;
var x2 = y1;

Fixes #16671 (comment)

[jablko]

transformers/ts.ts replaces import equals entity names with synthetic variable declarations + property access:

TypeScript/src/compiler/transformers/ts.ts

Line 2999 in 766e83f

const moduleReference = createExpressionFromEntityName(factory, node.moduleReference as EntityName);

I experimented with resolving the synthetic property access, but settled on saving and resolving the original entity name instead?

[weswigham]

This needs some dedicated tests (I don't see one testing the issue described in the OP) and a merge to resolve the conflicts.

[sandersn]

Do you want to keep working on this? Otherwise I'd like to close it to reduce the number of open PRs.

[Mifrill]

why changed?

I think it caused by following to:

TypeScript/tests/baselines/reference/constEnumPropertyAccess1.js

Line 22 in 88f80c7

var a1 = G["A"];