Jordan Rose ac2a9c06da When looking for conformances, make sure to check inherited conformances too. ...

Previously, if we were looking for, say, ForwardIndex conformance on Int,
we would see that Int is a BidirectionalIndex, and that BidirectionalIndex
refines ForwardIndex...but we'd have no way to get a conformance from
BidirectionalIndex (since it's not really BidirectionalIndex that conforms
to ForwardIndex, but rather Int-via-BidirectionalIndex). Change
Module::lookupConformance's helper findExplicitConformance to actually keep
conformance records around and walk those instead of just looking at the
ProtocolDecl's list of adopted protocols.

I don't have a minimal test case for this, but it fixes
<rdar://problem/15691181>, which allows DictionaryIndex to just adopt
BidirectionalIndex and have the ForwardIndex part be inferred. The problem
manifested as a crash in test/stdlib/Dictionary.swift, which just uses a
Dictionary in very basic ways, so I imagine we'll notice if this regresses.

Swift SVN r11521

2013-12-20 22:41:41 +00:00

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