Java: Improve virtual dispatch via better unification check and deduplicate code with parameterised module #10097
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aschackmull
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cc @ginsbach to check parameterised module usage. |
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Looks good to me from a parameterised modules perspective. |
aschackmull
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aschackmull
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Finally managed to get a decent-looking dca run. |
smowton
previously approved these changes
Aug 25, 2022
| or | ||
| failsUnification(t1.(Array).getComponentType(), t2.(Array).getComponentType()) | ||
| or | ||
| exists(RefType upperbound, RefType other | |
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Suggested change
| exists(RefType upperbound, RefType other | | |
| // Can't unify an `extends` bound against a concrete type that doesn't descend from that upper bound: | |
| exists(RefType upperbound, RefType other | |
| not other.getASourceSupertype*() = upperbound | ||
| ) | ||
| or | ||
| exists(RefType upperbound1, RefType upperbound2 | |
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Suggested change
| exists(RefType upperbound1, RefType upperbound2 | | |
| // Can't unify two `extends` bounds that don't intersect: | |
| exists(RefType upperbound1, RefType upperbound2 | |
| notHaveIntersection(upperbound1, upperbound2) | ||
| ) | ||
| or | ||
| exists(RefType lowerbound, RefType upperbound | |
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Suggested change
| exists(RefType lowerbound, RefType upperbound | | |
| // Can't unify `? super X` against `Y` or `? extends Y` where `Y` isn't an ancestor of `X`: | |
| exists(RefType lowerbound, RefType upperbound | |
| not lowerbound.getASourceSupertype*() = upperbound | ||
| ) | ||
| or | ||
| exists(BoundedType lowerbound, RefType upperbound | |
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Suggested change
| exists(BoundedType lowerbound, RefType upperbound | | |
| // Can't unify `? super T`, where `T` is a type variable `T extends S`, with a type that doesn't intersect with `S`: | |
| exists(BoundedType lowerbound, RefType upperbound | |
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| not lowerbound instanceof BoundedType | ||
| or | ||
| t2.(Wildcard).getLowerBoundType().(RefType).getSourceDeclaration() = lowerbound and | ||
| getUpperBound(t1).getSourceDeclaration() = upperbound and | ||
| not lowerbound instanceof BoundedType | ||
| | | ||
| not lowerbound.getASourceSupertype*() = upperbound |
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Suggested change
| not lowerbound instanceof BoundedType | |
| or | |
| t2.(Wildcard).getLowerBoundType().(RefType).getSourceDeclaration() = lowerbound and | |
| getUpperBound(t1).getSourceDeclaration() = upperbound and | |
| not lowerbound instanceof BoundedType | |
| | | |
| not lowerbound.getASourceSupertype*() = upperbound | |
| or | |
| t2.(Wildcard).getLowerBoundType().(RefType).getSourceDeclaration() = lowerbound and | |
| getUpperBound(t1).getSourceDeclaration() = upperbound and | |
| | | |
| not lowerbound instanceof BoundedType | |
| not lowerbound.getASourceSupertype*() = upperbound |
Fixed. |
hvitved
reviewed
Aug 29, 2022
hvitved
approved these changes
Aug 29, 2022
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The first commit is a pure refactor that changes all four copies of the unification code to instead use a single parameterised module.
The second commit improves the unification algorithm to account for the upper bounds of type variables and wildcards - until now the code assumed that all type variables and wildcards were merely
extends Objectand thus unifiable with anyRefType.The third commit also accounts for wildcards with lower bounds.