Slava Pestov 8928cb5b8a Sema: Stop using FunctionType::getOld() when generating constraints for SubscriptExpr ...

Previously we would generate the following constraint here, where
'index' and 'output' are concrete types and $input is a type
variable:

- ValueMember(base, $input -> output)
- ArgumentTupleConversion(index, $input)

The problem is that we built a function type where the entire input
was a type variable, which would then bind to an argument list.

We could instead generate this constraint:

- ValueMember(base, $member)
- ApplicableFunction(index -> output, $member)

I also had to redo how keypaths map locators back to key path
components. Previously the ArgumentTupleConversion was created
with a locator ending in KeyPathComponent.

Now the ApplicableFunction is created with this locator, which means
the argument match is performed with a locator ending in
ApplyArgument.

A consequence of this is that the SubscriptIndex and SubscriptResult
locator path elements are no longer used, so remove them.

This requires various mechanical changes in places we look at
locators to handle this change. Should be NFC.

2018-08-28 14:40:56 -07:00

6.6 KiB

Raw Blame History

View Raw