Sema: Ignore inactive type variables in addTypeVariableConstraintsToWorkList() #78888
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slavapestov
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I think this is okay but ultimately we want to notify constraint graph about the variables left in scope when forming ConjunctionStep::Snapshot - we currently only use removeConstraint to sever connections with outside type variables but that has no effect on already established connections through fixed types.
…orkList() Fixes a regression from commit 0c128e5. The old depthFirstSearch() walked all adjacencies via the constraint graph, and thus it would visit type variables that are currently inactive because we're solving a conjunction element. This was inconsistent with the new union-find which only formed the connected components from the currently active type variables; adjacencies involving inactive type variables are no longer considered. Fix the inconsistency by changing gatherConstraints(), which used from addTypeVariableConstraintsToWorkList(), to also skip inactive type variables. Fixes rdar://problem/143340082.
…therNearbyConstraints() The two GatherKinds no longer share any implementation, so there's no point keeping the logic together. Doing this also allows removing the acceptConstraintFn from gatherAllConstraints(), which further simplifies depthFirstSearch().
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@swift-ci Please test |
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Fixes a regression from commit 0c128e5.
The old depthFirstSearch() walked all adjacencies via the constraint graph,
and thus it would visit type variables that are currently inactive because
we're solving a conjunction element.
This was inconsistent with the new union-find which only formed the
connected components from the currently active type variables; adjacencies
involving inactive type variables are no longer considered.
Fix the inconsistency by changing gatherConstraints(), which used from
addTypeVariableConstraintsToWorkList(), to also skip inactive type
variables.
Fixes rdar://problem/143340082.