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4 commits

Author SHA1 Message Date
Nathan Shively-Sanders 8056e2b12f
infer from usage's unification uses multiple passes (#28244)
* infer from usage's unification uses multiple passes

Previously, the unification step of infer-from-usage codefix would stop
as soon an answer was found. Now it continues if the result is
*incomplete*, with the idea that later passes may provide a better
inference.

Currently, an *incomplete* inference is

1. The type any.
2. The empty object type `{}` or a union or intersection that contains
`{}`.

In the checker, any takes priority over other types since it basically
shuts down type checking. For type inference, however, any is one of the least
useful inferences.

`{}` is not a good inference for a similar reason; as a parameter
inference, it doesn't tell the caller much about what is expected, and
it doesn't allow the function author to use an object as expected. But
currently it's inferred whenever there's an initialisation with the
value `{}`. With this change, subsequent property assignments to the
same parameter will replace the `{}` with a specific anonymous type. For
example:

```js
function C(config) {
  if (config === undefined) config = {};
  this.x = config.x;
  this.y = config.y;
  this.z = config.z;
}
```

* Unify all passes of inference from usage

In the previous commit, I changed inference from usage to continue
inference if a the result was *incomplete*. This commit now runs all 4
inference passes and combines them in a unification step. Currently the
unification step is simple, it:

1. Gathers all inferences in a list.
2. Makes properties of anonymous types optional if there is an empty
object in the inference list.
3. Removes *vacuous* inferences.
4. Combines the type in a union.

An inference is *vacuous* if it:

1. Is any or void, when a non-any, non-void type is also inferred.
2. Is the empty object type, when an object type that is not empty is
also inferred.
3. Is an anonymous type, when a non-nullable, non-any, non-void,
non-anonymous type is also inferred.

I think I might eventually want a concept of priorities, like the
compiler's type parameter inference, but I don't have enough examples to
be sure yet.

Eventually, unification should have an additional step that examines the
whole inference list to see if its contents are collectively
meaningless. A good example is `null | undefined`, which is not useful.

* Remove isNumberOrString

* Unify anonymous types

@andy-ms pointed out that my empty object code was a special case of
merging all anonymous types from an inference and making properties
optional that are not in all the anonymous type. So I did that instead.

* Use getTypeOfSymbolAtLocation instead of Symbol.type!

* Unify parameter call-site inferences too

Because they still have a separate code path, they didn't use the new
unification code.

Also some cleanup from PR comments.

* Add object type unification test

Also remove dead code.

* Only use fallback if no inferences were found

Instead of relying on the unification code to remove the fallback.
2018-11-02 09:07:32 -07:00
Nathan Shively-Sanders fe2a33fcbc
Merge existing JSDoc comments (#27978)
* 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
2018-10-24 16:14:52 -07:00
Andy 854f20e90f
Remove 'verify.fileAfterCodeFix', use 'verify.codeFix' (#28110) 2018-10-24 15:34:15 -07:00
Nathan Shively-Sanders 88d3c6fd5f
inferFromUsage codefix now emits JSDoc in JS files (#27610)
* Now adding @type to variable declarations, at least

Probably everything else, but not as well.

* Improve @param output and add test

It's still bad, but at least it's not wrong.

* Add some js/inferFromUsage tests and fixes

Also, remove redundant is(Set|Get)Accessor functions.

* Fix @typedef refactor

* Emit JSDoc optional parameters

By surrounding the parameter name with brackets. It is super, super ugly
right now.

* Get rest of existing tests working

* Correct location of comments

* Handle @param blocks

1. Format multiple params nicely in a single-multiline block.
2. Generate only params that haven't already been documented. Existing
documentation is not touched.

* Re-add isGet/SetAccessor -- it is part of the API

* Move isSet/GetAccessor back to the original location

* Oh no I missed a newline and a space

* Switch to an object type

* A lot of cleanup

More to come, though. annotate is only called in
annotateVariableDeclaration where we don't know whether we're in JS or
not.

* Move and delegate to annotateJSDocParameters

* Address PR comments

* Lint: newline problems!!!!

* Switch another call to getNonformattedText

* Update baseline missed after merge
2018-10-09 10:38:46 -07:00