* Allow special property assignments in TS
But only for functions and constant variable declarations initialised with
functions.
This specifically excludes class declarations and class expressions,
which differs from Javascript. That's because Typescript supports
`static` properties, which are equivalent to property assignments to a
class.
* Improve contextual typing predicate
Don't think it's right yet, but probably closer?
* More fixes.
The code is still fantastically ugly, but everything works the way it
should.
Also update baselines, even where it is ill-advised.
* Cleanup
* Remove extra whitespace
* Some kind of fix to isAnyDeclarationName
It's not done yet.
Specifically, in TS:
Special property assignments are supposed to be declaration sites (but not all
top-level assignments), and I think I
got them to be. (But not sure).
In JS:
Special property assignments are supposed to be declaration sites (but not all
top-level assignments), and I'm pretty sure ALL top-level assignments
have been declaration sites for some time. This is incorrect, and
probably means the predicate needs to be the same for both dialects.
* Add fourslash and improve isAnyDeclarationName
Now JS behaves the same as TS.
* Cleanup from PR comments
* Lazily compute signature type predicates
* Use an instance of IdentifierTypePredicate to represent an unresolved type predicate
* Simplify `getMaybeTypePredicate`
* Invert representation of `resolvedTypePredicate`
* Remove `__unresolvedTypePredicate` type and remember to use `noTypePredicate` instead of `undefined` when in all `createSignature` calls
* Fix style of getTypePredicateOfSignature
* Use in createGetSymbolWalker
* Fix bugs for unions of type predicates
* Code review
* Make noTypePredicate purely an implementation detail of getTypePredictateOfSignature
* Add test
* Add test for #19642
* Add test with reversed order
