Fix getExpandoSymbol for already-expando symbols #36457
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getExpandoSymbol is intended to get the symbol of the expando in a
declaration like
```js
var C = class {
}
```
However, when this occurs in a `module.exports` assignment, alias
resolution already jumps to the exported symbol -- in this case the
expando symbol:
``js
// @filename: first.js
module.exports = class {
}
// @filename: other.js
/* @type {import("./first")} */
var C
```
`getExpandoSymbol` is then called on `class { }` instead of
`module.exports = class { }`.
Previously, `getExpandoSymbol` would incorrectly treat `class { }` the
same as the export assignment and get the expando ... from the expando
itself. This resulted in merging the expando with itself, which causes
bogus errors and could cause other problems.
Now `getExpandoSymbol` checks that the expando "initializer" is
different from the declaration.
Check the declaration directly instead of the initialiser.
andrewbranch
approved these changes
Jan 27, 2020
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getExpandoSymbolis intended to get the symbol of the expando in a declaration likeHowever, when this occurs in a
module.exportsassignment, alias resolution already jumps to the exported symbol -- in this case the expando symbol:getExpandoSymbolis then called onclass { }instead ofmodule.exports = class { }.Previously,
getExpandoSymbolwould incorrectly treatclass { }the same as the export assignment and get the expando ... from the expandoitself. This resulted in merging the expando with itself, which causes bogus errors in webpack and could cause other problems.
Now
getExpandoSymbolchecks that the declaration is not already an expando.Fixes #34809