...unless the argument is an `Any?`, in which case we prefer `f(_: Any?)`.
This change also results in our selecting f<T>(_: T) over f(_:
Any). Coercing with 'as Any' makes it possible to explicitly select
the Any overload. Previously there was no way to select the generic
overload.
Treat non-optional generic parameters as being more specialized than
optional generic parameters, and penalize any solutions that involve
generic arguments that are themselves Optional.
By doing these things, we can remove the special-cased code for the
two overloads of '??' in the stdlib, instead treating the (T?, T)
overload as better than the (T?, T?) overload except where a user
actually passes an optionally-typed value as the second parameter.
Fixes: rdar://problem/19748710
Refactor the interface to return a bit vector. Along the way, fix up
the callers and remove some dead usages of the defaults information
that were copied and pasted around Sema.
Normally we wouldn't need this because we do not allow overloading by
parameter optionality. In this case, though, we import two Objective-C
methods that end up getting renamed to the same name in Swift, one of
which has a nullability annotation and the other of which doesn't.
Before IUOs were removed from the type system, we would have failed a
subtype test when ranking overloads, but now that subtype test passes
because we're comparing two optionals of the same type. So the change
here is to compare the optionality of the parameters and reject cases
where we are testing whether a plain optional is a subtype of
something declared to be an IUO.
Fixes rdar://problem/38719575.
- Reuse existing logic to curry the signature type with the 'self' of the context (in addition we no longer use a MetatypeType for the 'self' of a static member as they don't have conflicting signatures with instance members anyway)
- Limit the fix for SR-7251 to Swift 5 mode
- Add tests for generic subscripts
Currently we always use 'FunctionResult' as a path element when matching
function result types, but closure result type is allowed to be implicitly
converted to Void, which means we need to be careful when to use
'FunctionResult' and 'ClosureResult'.
Resolves: rdar://problem/37790062
* Implement the recently accepted SE-0195 proposal, which introduces "Dynamic
Member Lookup" Types. This is a dusted off and updated version of PR13361,
which switches from DynamicMemberLookupProtocol to @dynamicMemberLookup as
was requested by the final review decision. This also rebases it,
updates it for other changes in the compiler, fixes a bunch of bugs, and adds support for keypaths.
Thank you to @rudx and @DougGregor in particular for the helpful review comments and test cases!
This partially reverts commit 8685ee01a1.
The tests are still in place, but the code change is no longer necessary
now that IUOs are removed from the type system.
Fixes: rdar://problem/37013789
Allow passing Optional<T> as inout where
ImplicitlyUnwrappedOptional<T> is expected, and vice-versa.
Swift 4.1 added a warning that overloading inouts by kind of optional
was deprecated and would be removed, but we didn't actually allow
people to remove an overload and pass arguments of the other kind of
optional to the remaining function.
Fixes rdar://problem/36913150
When binding an optional value, or function that returns an optional
value, if that value was produced from a decl that was declared an
IUO, create a disjunction.
After solving, make use of the disjunction choices in rewriting
expressions to force optionals where needed.
This is disabled for now, as it results in a source compatibility
issue without associated changes that actually start generating
Optional<T> in place of ImplicitlyUnwrappedOptional<T>. It's
complicated, but basically having two '??' (one returning T, one
returning T?) and creating a disjunction where the first (favored)
choice is ImplicitlyUnwrappedOptional<T> and second is T results in
our selecting the wrong '??' in some cases.
Use this in places where we have a decl that is marked with the
ImplicitlyUnwrappedOptionalAttr so that we can distinguish in the
solver which decls need to be potentially unwrapped in order to type
check successfully.
Add a new OverloadChoiceKind for decls that are either IUO-typed, or
function-typed meaning that the function result type is IUO-typed.
Not currently used, so NFC.
If default'ed parameters in one decl are intermixed with non-defaulted
ones, skip claiming parameters in other decl at the same position.
Resolves: rdar://problem/36226874.
For the purposes of partial ordering of declarations (e.g., in
overload resolution), adjust `@autoclosure` parameter types to the
result type of the autoclosure, i.e., the type against which the
argument will be matched. This makes overload resoluton agnostic to
`@autoclosure`.
Fixes SR-6472.
conformsToProtocol() is the main way in which we check whether a given type
conforms to a given protocol. Extend it to check conditional requirements by
default, so that an unmodified caller will get the "does not conform" result
(with diagnostics when a location is present) rather than simply ignoring
the conditional requirements.
Some callers take responsibility for conditional requirements, e.g., to
push them into the constraint system. Allow those callers to opt out of
this checking, and do so wherever appropriate.
Fixes rdar://problem/35518088, where we were ignoring the conditional
requirements needed to verify that Equatable synthesis could be performed.
Consider different overload choices for the same location in evaluation
order, this makes overload resolution more predictable because it's going
to follow expression bottom-up, that prevents situations when some
expressions are considered ambigious because choices taken further up
equate the score, instead each level is given distinct weight
based on evaluation order.
Resolves: rdar://problem/31888810
Except GenericEnvironment.h, because you can't meaningfully use a
GenericEnvironment without its signature. Lots less depends on
GenericSignature.h now. NFC
This hack was originally intended to distinguish between functions
of single arguments that were overloaded on AnyObject and AnyObject?.
Nowadays, CSRanking is capable of handling that itself, and the check
this function was using to detect AnyObject no longer works.
This doesn't appear to be necessary when name lookup
does the right thing.
We don't *want* Sema to consider overload sets
containing both a protocol requirement and a witness,
because this could lead to exponential behavior.
If class property with the same name has been found on both subclass and superclass,
let's always prefer subclass with all else equal, because subclass property
could only be found if requested directly.
Resolves: rdar://problem/32973206
In some situations e.g. while trying to shrink domains of the type
variables before attempting search, use a flag to tell constraint
system to retain all of the viable solutions otherwise solver could
loose some of the information required to produce complete solution.
Resolves: rdar://problem/32726044
AnyFunctionType::Param carries around information about decomposed
parameters now. Information about default arguments must be computed
separately with swift::computeDefaultMap.
Instead of having three different scores for - string, array, inout,
let's unify them under a single value-to-pointer score and use
it in appropriate places when simplifying restricted constraints.
There are possible situations when we find solutions with String
and String -> UnsafePointer conversions at the same time for
expressions with default string literals. In order to disambiguite
such situations let's prefer solutions without String -> UnsafePointer
conversions if possible.
With the introduction of special decl names, `Identifier getName()` on
`ValueDecl` will be removed and pushed down to nominal declarations
whose name is guaranteed not to be special. Prepare for this by calling
to `DeclBaseName getBaseName()` instead where appropriate.
The openType() function did two things:
- Replace unbound generic types like 'G' with fresh type variables
applied to bound generic types, like 'G<$T0>'.
- Replace generic parameters with type variables from the replacement
map.
The two behaviors were mutually exclusive and never used from the
same call site, so split them up into two independent functions.
Also, eliminate ConstraintSystem::openBindingType() since it was only
used in one place and could be expressed in terms of existing functions.
