[AST] Avoid flattening type variable tuple singletons #86647
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If we have `(_: $T0)`, avoid flattening to `$T0` since for a pack expansion type variable that would result in a bare pack type instead of a tuple. Instead, leave the flattening for TypeSimplifier.
This only seemed to exist to stop type variable tuple singletons from being flattened, but that's now always the behavior.
hamishknight
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hborla,
slavapestov and
xedin
as code owners
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@swift-ci please test |
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Author
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@swift-ci please test source compatibility |
xedin
reviewed
Jan 20, 2026
| // flattening in this case. | ||
| if (elements.size() == 1 && | ||
| !elements[0].getType()->is<PackExpansionType>() && | ||
| !elements[0].getType()->is<TypeVariableType>() && |
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Probably if it’s a type variable and can bind to a pack?
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If we have
(_: $T0), avoid flattening to$T0since for a pack expansion type variable that would result in a bare pack type instead of a tuple. Instead, leave the flattening for TypeSimplifier.Resolves #86629
Resolves #86628
rdar://168407842&168407626