Instantiate contextual types for return expressions

[Anders Hejlsberg (ahejlsberg)]

Fixes#32349.

[Anders Hejlsberg (ahejlsberg)]

TypeScript Bot (@typescript-bot) run dt
TypeScript Bot (@typescript-bot) test this

[TypeScript Bot (typescript-bot)]

Heya Anders Hejlsberg (@ahejlsberg), I've started to run the parallelized Definitely Typed test suite on this PR at 6f637b0. You can monitor the build here. It should now contribute to this PR's status checks.

[TypeScript Bot (typescript-bot)]

Heya Anders Hejlsberg (@ahejlsberg), I've started to run the extended test suite on this PR at 6f637b0. You can monitor the build here. It should now contribute to this PR's status checks.

[Anders Hejlsberg (ahejlsberg)]

DT test failures look like preexisting conditions unrelated to this PR.

RWC tests have one failure that boils down to this:

declarefunctionfoo<T>(x: T|Promise<T>): void;declareletb: false|Promise<true>;foo(b);// Error

We fail to infer boolean for T, instead inferring just true. The issue is the way we give lower priority to direct inferences to naked type parameters in unions. I will think about ways to fix this.

[Anders Hejlsberg (ahejlsberg)]

Verified that there are no differences in RWC tests between this and the master branch.

[Anders Hejlsberg (ahejlsberg)]

So, now that #32460 is in and RWC is clean, I'm going to merge this.