* Set-only accessors spread to undefined
Previously they were skipped. The runtime behaviour is to create a
property of type undefined, unlike (for example) spreading numbers or
other primitives. So now spreading a set-only accessor creates a
property of type undefined:
```ts
const o: { foo: undefined } = { ...{ set foo(v: number) { } } }
```
Notably, `o.foo: undefined` not `number`.
Fixes#26337
* Fix isSpreadableProperty oversimplification
* Measure variance of aliased conditional types using variance markers
* Just do variance probing for all type aliases
* Small limiter for predictability
* Inline property set, remove unused functions
* Do not merge commonsjs exports onto an alias
getCommonJSExportEquals merges export assignments and export property
assignments. Something like this, which has no equivalent structure in
TS:
```js
module.exports = function() { }
module.exports.expando = 1
```
However, it is sometimes called with an alias, when its
parent, resolveExternalModuleSymbol, is called with dontResolveAlias:
true, and when the initialiser of the export assignment is an alias:
```js
function alias() { }
module.exports = alias
module.exports.expando = 1
```
In this case, (1) the actual value `alias` will have already merged in a
previous call to getCommonJSExportEquals and
(2) getTypeOfSymbol will follow the alias symbol to get the right type.
So getCommonJSExportEquals should do nothing in this case.
This bug manifests in the code for dynamic imports, which calls
getTypeOfSymbol on the incorrectly merged alias, which now has enough
value flags--Function, for example--to take the wrong branch and
subsequently crash.
* Update baselines
* Correct indentation, using correct (I hope) indentation code
Note that part of the code, in formatting.ts, is cloned but should be
extracted to a function instead.
* Remove some possibly-superfluous code
But I see 4 failures with whitespace, so perhaps not.
* Restrict indentation change to avoid breaking baselines
The indentation code is very complex so I'm just going to avoid breaking
our single-line tests for now, plus add a simple jsdoc test to show that
multiline jsdoc indentation isn't destroyed in the common case.
* Switched over to construction for @return/@type
Still doesn't merge correctly though
* Add @return tags to emitter
* Merge multiple jsdocs
(not for @param yet)
* Merge multiple jsdoc for parameters too
* Emit more jsdoc tags
Not all of them; I got cold feet since I'll have to write tests for
them. I'll do that tomorrow.
* Many fixes to JSDoc emit
And single tests (at least) for all tags
* Cleanup in textChanges.ts
* Cleanup in formatting.ts
(Plus a little more in textChanges.ts)
* Cleanup in inferFromUsage.ts
* Fix minor omissions
* Separate merged top-level JSDoc comments with \n
instead of space.
* Don't delete intrusive non-jsdoc comments
* Cleanup from PR comments
1. Refactor emit code into smaller functions.
2. Preceding-whitespace utility is slightly easier to use.
3. Better casts and types in inferFromUsage make it easier to read.
* Fix bogus newline
* Use @andy-ms' cleanup annotateJSDocParameters
* Obey the excludeArgument parameter when checking JSX signature validity
* Fix conditional type extending any contextual types and accept baselines
* use flag check to also drop unknown from comparison for the same reason
* Slight refinement - make an intersection to ensure parameter constraints flow through contextual types when instantiated
* Format ternary more nicely
