[CSOptimizer] A few improvements to inference and ranking #79309
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… matching Result type should only be matched if there are matches on arguments or there are no viable candidates.
For example, `??` operator could produce an optional type so `test(<<something>> ?? 0) could result in an optional argument that wraps a type variable. It should be possible to infer bindings from underlying type variable and restore optionality.
This used to be limited to Double/CGFloat and operator arguments but it's safe to do in general.
Since each candidate and overload choice are considered independenty there is no way to judge whether non-default literal type is going to result in a worse solution than non-default one.
… to a constructor
…sely Having it be part of the other matching wasn't a good idea because previous "favoring" happened only in a few situations - if argument was a declaration reference, application or (dynamic) subscript that had overload choice selected during constraint generation.
Disjunction with a single element are not always introduced after disfavoring, so we need to make sure that they are always preferred during disjunction selection.
Since such choices are all but guaranteed to be worst than any other non-disfavored choice, let's attempt them last to avoid having to form a complete solution just to filter it out during ranking.
Optimizer now covers all of the most common ExpressibleBy*Literal protocols.
…ures If there are no-same type requirements and parameters use either concrete types or generic parameter types directly, the optimizer should be able to handle ranking. Currently candidate arguments are considered in isolation which makes it impossible to deal with same-type requirements and complex generic signatures.
…e considered Some of the disjunctions are not supported by the optimizers but could still be a better choice than an operator. Using a non-score based preference mechanism first allows us to make sure that operator disjunctions are not selected too eagerly in some situations when i.e. a member (supported or not) could be a better choice.
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@swift-ci please test |
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@swift-ci please test source compatibility |
slavapestov
reviewed
Feb 12, 2025
| // that use only concrete types or generic parameters directly | ||
| // in their parameter positions i.e. `(T, Int)`. | ||
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| auto *paramList = getParameterList(decl); |
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Since you have a GenericFunctionType here, maybe just look at choiceType->getParams()?
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I think that would mean that I would have to look through self for instance members and I just didn’t want to mess with that…
| return {/*score=*/0}; | ||
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| auto argumentType = cs.getType(argument); | ||
| if (argumentType->hasTypeVariable() || argumentType->hasDependentMember()) |
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Is it possible for hasDependentMember() to return true while hasTypeVariable() returns false?
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Yeah, solver would form dependent member types when base is invalid as well
…neric standard comparison ones Disfavor standard comparison operators when other wise has some non-generic favored choices. Operators like `==` and `!=` tend to get multiple generic matches through conformance to `Equatable` and it's better to attempt them as a last resort.
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@swift-ci please test |
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@swift-ci please test source compatibility |
This was referenced Feb 12, 2025
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CGFloatas a contextual result typeDoubleandCGFloat??operator