Slava Pestov bcee54b936 GSB: The combination of a superclass and conformance requirement might force a type to be concrete ...

A protocol can constrain an associated type to Self:

    protocol P {
      associatedtype A : Q where A.B == Self
    }

    protocol Q {
      associatedtype B
    }

And a class might conform to this protocol:

    class C : P {
      typealias A = D
    }

    class D : Q {
      typealias B = C
    }

The generic signature <Self where Self : P, Self : C> is built during
conformance checking. Since Self : C, we must have that Self.A == D;
since D.B == C, the requierement 'A.B == Self' in protocol P implies
that 'Self == C'. So the correct minimized signature here is
<Self where Self == C>.

This wasn't handled properly before, because of assumptions in
removeSelfDerived() and a couple of other places.

Fixes rdar://71677712, rdar://76155506, https://bugs.swift.org/browse/SR-10033,
https://bugs.swift.org/browse/SR-13884.

2021-04-03 23:04:39 -04:00

..

0208-sr8751.swift

[Test] Disable two tests that hang asan bots.

2020-07-14 16:23:38 -07:00

sr8968.swift

GSB: Move signature verification from CanGenericSignature::getCanonical() to computeGenericSignature()

2021-03-11 21:07:33 -05:00