[5.3] [CS] Avoid checking RHS of one-way constraint for reactivation #32693
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Previously we would only gather one-way constraints if they were found through a type variable in their right hand side. However we would incorrectly check this against the type variable that we started the search at. This meant that if the constraint was found through a fixed binding, we would never return it, and could therefore fail to re-activate it, leaving it unsolved. Fix this issue by simply removing the check for the RHS, and letting the constraint system handle it instead. Resolves rdar://64890308.
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@swift-ci please test |
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@swift-ci please test source compatibility |
DougGregor
approved these changes
Jul 2, 2020
AnthonyLatsis
added
swift 5.3
🍒 release cherry pick
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5.3 cherry-pick of #32673.
Explanation: Fixes a compiler crash that can potentially occur when using a function builder.
Scope: Fixes a 5.3 regression with function builders.
Radar: rdar://64890308
Risk: Medium-low: The fix modifies constraint re-activation, but is isolated to one-way constraints that haven't split the constraint system, and will cause us to re-activate strictly more constraints.
Testing: Added unit test.
Reviewer: @xedin