If key path literal is converted to a read-only type, let's not
use maximum mutability to avoid unnecessary conversions. This is
also important because accessor references are availability checked
and we need to avoid referencing something that is not actually
going to be used.
There are some edge-cases in this approach which would still
produce a conversions, i.e.:
```
struct S {
var a: Int
let b: Int
}
func test<T>(_: T, _: T) {}
test(\S.a, \S.b)
```
Here `\S.a` is going to be converted to `KeyPath<S, Int>`. Availability
checker would still have to recognize situations like that and skip
checking setters if they are not used.
If we have a hole binding for the result of a closure, avoid
introducing Void as an additional binding since that'll just cause
local solution ambiguities. This doesn't affect regular type-checking
since we end up treating such ambiguities as "identical", so we just
pick one. But for completion, we don't do such filtering so need to
make sure we end up with the hole solution to avoid treating Void as
the contextual type for cases such as:
```
_ = {
x.#^CC^#
}
```
Currently we avoid this by not handling holes in `repairFailures`
for closure body locators, but I'm changing that in the next commit.
The original attempt to do this was reverted by https://github.com/swiftlang/swift/pull/77653
The problem is that the fix was too broad, I narrowed it down to
non-exact uses of stdlib collections that support upcasts.
(cherry picked from commit b7e7493076)
Additional restrictions on when protocol inference could be considered
viable. If the chain is connected directly to a contextual type there
cannot be any other inference sources for the base type.
Resolves: rdar://148256978
Transitively inferring a protocol type binding from a contextual
type means that the binding set for a leading-dot member reference
is complete because there could be no other sources of bindings
when expression is connected directly to a contextual type.
Resolves: rdar://145103149
Within the constraint system, introduce a new kind of conformance constraint,
a "nonisolated conforms-to" constraint, which can only be satisfied by
nonisolated conformances. Introduce this constraint instead of the normal
conforms-to constraint whenever the subject type is a type parameter that
has either a `Sendable` or `SendableMetatype` constraint, i.e., when the type
or its values can escape the current isolation domain.
* Revert "[CSOptimizer] Look through `OptionalEvaluationExpr`s when dealing with unapplied disjunctions"
This reverts commit 72340f39b8.
* Revert "[CSOptimizer] Don't consider disabled overloads when checking whether disjunction is supported"
This reverts commit 6bc23b5057.
* Revert "[CSOptimizer] Disjunctions with IUO overload choices are unsupported"
This reverts commit 471ee21535.
* Revert "[CSOptimizer] MemberImportVisibility: Don't consider overloads that come from implicit imports"
This reverts commit aa4a2b9071.
* Revert "[CSOptimizer] Don't consider CGFloat widening when explicit initializer is used"
This reverts commit 3cc76eacdd.
* Revert "[CSOptimizer] Literal arguments should cause score reset only for operators"
This reverts commit e3987beffb.
* Revert "[CSOptimizer] NFC: check whether a choice is of operator instead of whole disjunction"
This reverts commit 6c82892c3c.
* Revert "[CSOptimizer/Tests] NFC: Add a perf test-case fixed by improved literal array handling"
This reverts commit cfd34e54c4.
* Revert "[CSOptimizer] Extend candidate/parameter matching to support array literals"
This reverts commit 8a304f88c6.
* Revert "[CSOptimizer] Favor choices that don't require application"
This reverts commit 0737542da8.
* Revert "[CSOptimizer] Disable CGFloat -> Double conversion for unary operators"
This reverts commit bc3a15fbe6.
* Revert "[CSOptimizer] Mark bitwise operators as supported"
This reverts commit 860ae08d1b.
* Revert "[CSOptimizer] Simplify handling of non-applied disjunctions"
This reverts commit 43ca7dfff9.
* Revert "[ConstraintSystem] Fix `getEffectiveOverloadType` handling of `mutating` methods"
This reverts commit c767f7aff7.
* Revert "[CSOptimizer] Reduce overload types before ranking"
This reverts commit 95b47aead6.
* Revert "[CSOptimizer] Implement special prioritization rules for result builder contexts"
This reverts commit 56d6635e46.
* Revert "[CSOptimizer] Allow only widening CGFloat->Double conversions while matching candidate arguments"
This reverts commit bf8ae3bc1b.
* Revert "[CSSimplify] CGFloat-Double: Rank narrowing correctly when result is injected into an optional"
This reverts commit cb876cbd9e.
* Revert "[CSBindings] Prevent `BindingSet::isViable` from dropping viable bindings (v2)"
This reverts commit b7e7493076.
* Revert "[CSOptimizer] Add support for chained members without arguments"
This reverts commit 87cd5f8733.
* Revert "[CSOptimizer] Mark compiler synthesized disjunctions as optimized"
This reverts commit 867e64182f.
* Revert "[CSOptimizer] Make a light-weight generic overload check if some requirements are unsatisfiable"
This reverts commit 15c773b9d7.
* Revert "[CSOptimizer] Fix `selectDisjunction` to use favored choices even if disjunction was not optimized"
This reverts commit c2a55886f0.
* Revert "[CSOptimizer] Limit "old" behavior compatibility to unlabeled unary arguments"
This reverts commit 9fb73143f6.
* Revert "[Tests] NFC: Update a couple of type-checker tests"
This reverts commit ff8663ff16.
* Revert "[Tests] NFC: Move simd related test-case from `slow` to `fast`"
This reverts commit 28396a6dce.
* Revert "[CSGen] NFC: Remove obsolete `ConstraintSystem::{get, set}FavoredType`"
This reverts commit 8bd288447f.
* Revert "[CSOptimizer] Allow literal arguments to match parameters that conform to `ExpressibleBy{Integer, Float}Literal`"
This reverts commit 2fdd4b6c35.
* Revert "[CSOptimizer] Adjust `scoreCandidateMatch` to indicate when match cannot be decided"
This reverts commit 9b62c84a4f.
* Revert "[CSOptimizer] Fix Double<->CGFloat implicit conversion support when arguments are literals"
This reverts commit 6caf1ccbb2.
* Revert "[CSOptimizer] A more comprehensive generic overload checking when candidates are fully resolved"
This reverts commit e30587bda4.
* Revert "[CSOptimizer] Restore old hack behavior which used to favor overloads based on arity matches"
This reverts commit a3a3ec4fe0.
* Revert "[CSOptimizer] Desugar types before checking for equality"
This reverts commit 802f5cd105.
* Revert "[ConstraintSystem] Narrowly disable `tryOptimizeGenericDisjunction` when some of the arguments are number literals"
This reverts commit 8d5cb112ef.
* Revert "[CSOptimizer] Infer argument candidates from calls to `Double` and CGFloat constructors"
This reverts commit f2a6677a6d.
* Revert "[CSOptimizer] Score all of the overload choices matching on literals uniformly"
This reverts commit 59109c2d60.
* Revert "[CSOptimizer] Enable ranking of `Int*`, `Float{80}` and `Double` initializers"
This reverts commit 6fb6d1cf90.
* Revert "[CSOptimizer] Rank disjunctions based on score only if both sides are supported"
This reverts commit 8818d399f9.
* Revert "[CSOptimizer] Rank results of operators regardless of whether anything is known about parameters"
This reverts commit 3996b25fbd.
* Revert "[Tests] NFC: Add more test-cases that were previously solved due to old hacks behavior"
This reverts commit d0ff6c81b8.
* Revert "[CSOptimizer] Average score should reflect number of defaulted parameters"
This reverts commit 23589add74.
* Revert "[Tests] NFC: Adjust a couple of improved tests"
This reverts commit 66981364fe.
* Revert "[CSOptimizer] Don't optimize (implicit) calls with code completion arguments"
This reverts commit 8a918e2369.
* Revert "[CSOptimizer] attempt to rank only standard/simd operators and fully concrete overload sets"
This reverts commit deca9b61c5.
* Revert "[CSOptimizer] Record best scores for each disjunction and use them in `selectDisjunction`"
This reverts commit 3819ddfb40.
* Revert "[CSOptimizer] Let `determineBestChoicesInContext` return the best disjunction if one is available"
This reverts commit cf05405eae.
* Revert "[CSOptimizer] Emulate old behavior related to favoring of unary calls to members"
This reverts commit 527de22bec.
* Revert "[Tests] NFC: Add a test-case for rdar://133340307 which is now fast"
This reverts commit 670127abd6.
* Revert "[CSOptimizer] Prefer homogeneous arithmetic operator overloads when argument(s) or result match"
This reverts commit d69b6a0594.
* Revert "[CSOptimizer] Remove an outdated optimization to compare resolved argument types with all else equal"
This reverts commit 1760bd1f1e.
* Revert "[CSOptimizer] NFC: Switch from llvm::Optional to std::optional post-rebase"
This reverts commit c429f5b9ec.
* Revert "[CSOptimizer] Increase score when type matches opaque type"
This reverts commit 2869dff995.
* Revert "[CSOptimizer] NFC: Switch to llvm::Optional"
This reverts commit 0fc6806922.
* Revert "[CSOptimizer] NFC: Adjust conformance check to use `ConstraintSystem::lookupConformance`"
This reverts commit da65333d41.
* Revert "[CSOptimizer] Treat all type parameters equally"
This reverts commit 957a5f4270.
* Revert "[CSStep] Remove disjunction pruning logic from DisjunctionStep"
This reverts commit 2c44e37948.
* Revert "[CSOptimizer] Relax candidate type requirements from equality to set of no-impact conversions"
This reverts commit 11b897b32f.
* Revert "[CSOptimizer] Use `matchCallArguments` to establish argument-to-parameter relationships"
This reverts commit cb1cb2018d.
* Revert "[CSOptimizer] Don't attempt to optimize calls with code completion token(s) in argument position"
This reverts commit 14e2a16fce.
* Revert "[CSOptimizer] Allow generic operator overloads without associated type parameters"
This reverts commit bc5f70a9a3.
* Revert "[CSOptimizer] Make sure that all parameters without arguments are defaulted"
This reverts commit 7c1c46d4e4.
* Revert "[CSStep] Don't favor choices until the disjunction is picked"
This reverts commit e404ed722a.
* Revert "[CSOptimizer] Keep track of mismatches while evaluating candidates"
This reverts commit a094c3ebb0.
* Revert "[CSOptimizer] Favor SIMD related arithmetic operator choices if argument is SIMD<N> type"
This reverts commit c2f7451c7b.
* Revert "[CSOptimizer] Initial implementation of disjunction choice favoring algorithm"
This reverts commit 672ae3d252.
* Revert "[ConstraintSystem] Add skeleton of constraint optimizer"
This reverts commit b5f08a4009.
* Revert "[CSGen] Remove ConstraintOptimizer and all favoring logic"
This reverts commit 4432c51f57.
* Revert "[ConstraintSystem] Remove `shrink`"
This reverts commit 757ca24e8a.
* [TypeChecker] NFC: Remove resurrected use of `SolverShrinkUnsolvedThreshold`
* [TypeChecker] Bring back `SolverDisableShrink`
* [Tests] NFC: Mark tests affected by solver-perf revert as slow
* [Tests] NFC: Adjust async tests that are affected by performance hacks
When doing completion in a result builder, we avoid
solving unrelated expressions by replacing them with
unbound placeholder variables. Avoid penalizing
assigning holes to these placeholders, since
otherwise we end up unnecessarily exploring the
entire solution space, and bailing due to too
complex.
rdar://144382123
Instead of making an undo() do an infer(), let's record fine-grained
changes about what was retracted, and directly re-insert the same
elements into the data structures.
We don't want to do that in general because injection should happen
only in one place but Void is special because it allows conversions
in that position.
Let's not perform $T? -> $T for closure result types to avoid having
to re-discover solutions that differ only in location of optional
injection.
The pattern with such type variables is:
```
$T_body <conv/subtype> $T_result <conv/subtype> $T_contextual_result
```
When `$T_contextual_result` is `Optional<$U>`, the optional injection
can either happen from `$T_body` or from `$T_result` (if `return`
expression is non-optional), if we allow both the solver would
find two solutions that differ only in location of optional
injection.
The original attempt to do this was reverted by https://github.com/swiftlang/swift/pull/77653
The problem is that the fix was too broad, I narrowed it down to
non-exact uses of stdlib collections that support upcasts.
PotentialBindings is part of ConstraintGraphNode and there's no need
to store the ConstraintSystem and TypeVariableType twice.
Also it doesn't need to be optional either, because we no longer need
to reset and recompute bindings.
All but two remaining call sites can be changed to just check for a
non-null solverState, because we want to assert if we're inside
of an active undo.
The two places inside binding inference can check isUndoActive()
directly.
Until `ApplicableFunction` constraint is simplified result type
associated with it cannot be bound because the binding set if
incomplete.
Resolves: rdar://139237088
Delaying such bindings is too restrictive and leads to subpar selections.
For `$T1` to be array or C-style pointer it would have to be
connected either to a type variable that could be bound to
array/pointer or directly to array/pointer type which would
result in the solver either selecting the other type variable
first (because it appears in adjacent variables of `$T1`) or
provide an additional binding(s) for `$T1` (including literals).
Consider the following constraint system:
```
$T2 arg conv $T1
$T2 conforms ExpressibleByIntegerLiteral
inout $T1 arg conv UnsafeMutablePointer<UInt8>?
```
If `$T1` and `$T2` are the only viable type variables delaying
`$T1` would mean that `$T2` is picked to attempt its default
type `Int` which is incorrect (it doesn't get `UInt8` because
there is no transitive inference through conversions).
Tuples in general do have conversions but an empty tuple or `Void`
doesn't, which means that if a type variable has a subtype binding
to `Void` it should be safe to prioritize.
