Since getSpecifier() now kicks off a request instead of always
returning what was previously set, we can't pass a ParamSpecifier
to the ParamDecl constructor anymore. Instead, callers either
call setSpecifier() if the ParamDecl is synthesized, or they
rely on the request, which can compute the specifier in three
specific cases:
- Ordinary parsed parameters get their specifier from the TypeRepr.
- The 'self' parameter's specifier is based on the self access kind.
- Accessor parameters are either the 'newValue' parameter of a
setter, or a cloned subscript parameter.
For closure parameters with inferred types, we still end up
calling setSpecifier() twice, once to set the initial defalut
value and a second time when applying the solution in the
case that we inferred an 'inout' specifier. In practice this
should not be a big problem because expression type checking
walks the AST in a pre-determined order anyway.
The autoclosures generated for the keypath-as-function feature were not added to the list of closures that needed captures computed. In top-level code, this caused a crash. Fixes rdar://problem/56055600.
Structurally prevent a number of common anti-patterns involving generic
signatures by separating the interface into GenericSignature and the
implementation into GenericSignatureBase. In particular, this allows
the comparison operators to be deleted which forces callers to
canonicalize the signature or ask to compare pointers explicitly.
Computing the interface type of a typealias used to push validation forward and recompute the interface type on the fly. This was fragile and inconsistent with the way interface types are computed in the rest of the decls. Separate these two notions, and plumb through explicit interface type computations with the same "computeType" idiom. This will better allow us to identify the places where we have to force an interface type computation.
Also remove access to the underlying type loc. It's now just a cache location the underlying type request will use. Push a type repr accessor to the places that need it, and push the underlying type accessor for everywhere else. Getting the structural type is still preferred for pre-validated computations.
This required the resetting of a number of places where we were - in many cases tacitly - asking the question "does the interface type exist". This enables the removal of validateDeclForNameLookup
Add a new type of diagnostic transaction, CompoundDiagnosticTransaction.
The first diagnostic emitted inside the transaction will become the parent of the subsequent notes.
DiagnosticConsumers may opt in to consuming these child notes alongside the parent
diagnostic, or they can continue to consider them seperately.
Moved PrintingDiagnosticConsumer and a couple of diagnostics to the new
system as a proof of concept.
When diagnosing failures in a function builder closure, we were
unnecessarily replacing the closure expression with its body,
destroying the AST and resulting in assertions due to DeclContext
mismatches. Fixes SR-11350 / rdar://problem/54590425.
In order to do this we need it to take a ConstraintLocator argument so
we can tell which component we want the callee for. To make it clear
that we're looking for a callee at the anchor, also rename the member
to getAnchormostCalleeLocator.
Obviously we won't have a disjunction choice for the locator, it's only possible if the locator is extended with ImplicitlyUnwrappedDisjunctionChoice path element
Introduce callables: values of types that declare `func callAsFunction`
methods can be called like functions. The call syntax is shorthand for
applying `func callAsFunction` methods.
```swift
struct Adder {
var base: Int
func callAsFunction(_ x: Int) -> Int {
return x + base
}
}
var adder = Adder(base: 3)
adder(10) // desugars to `adder.callAsFunction(10)`
```
`func callAsFunction` argument labels are required at call sites.
Multiple `func callAsFunction` methods on a single type are supported.
`mutating func callAsFunction` is supported.
SR-11378 tracks improving `callAsFunction` diagnostics.
We've fixed a number of bugs recently where callers did not expect
to get a null Type out of subst(). This occurs particularly often
in SourceKit, where the input AST is often invalid and the types
resulting from substitution are mostly used for display.
Let's fix all these potential problems in one fell swoop by changing
subst() to always return a Type, possibly one containing ErrorTypes.
Only a couple of places depended on the old behavior, and they were
easy enough to change from checking for a null Type to checking if
the result responds with true to hasError().
Also while we're at it, simplify a few call sites of subst().
This commit replaces the `getValue()` and `getValue2()` members on
`ConstraintLocator::PathElement` with specific accessors for each
expected path component kind. IMO this adds some clarity to the call
sites, especially for `getArgIdx()` and `getParamIdx()`.
In addition, this commit adds a private `getValue` member that can
access a value at a given index, which will make it easier to add a
third value in the future.
One-way constraint expressions, which are the only things that
introduce one-way constraints at this point, want to look through
lvalue types to produce values. Rename OneWayBind to OneWayEqual, map
it down to an Equal constraint when it is simplified (to drop
lvalue-ness), and apply that coercion during constraint application.
Part of rdar://problem/50150793.
The only place this was used in Decl.h was the failability kind of a
constructor.
I decided to replace this with a boolean isFailable() bit. Now that
we have isImplicitlyUnwrappedOptional(), it seems to make more sense
to not have ConstructorDecl represent redundant information which
might not be internally consistent.
Most callers of getFailability() actually only care if the result is
failable or not; the few callers that care about it being IUO can
check isImplicitlyUnwrappedOptional() as well.
Introduce the notion of "one-way" binding constraints of the form
$T0 one-way bind to $T1
which treats the type variables $T0 and $T1 as independent up until
the point where $T1 simplifies down to a concrete type, at which point
$T0 will be bound to that concrete type. $T0 won't be bound in any
other way, so type information ends up being propagated right-to-left,
only. This allows a constraint system to be broken up in more
components that are solved independently. Specifically, the connected
components algorithm now proceeds as follows:
1. Compute connected components, excluding one-way constraints from
consideration.
2. Compute a directed graph amongst the components using only the
one-way constraints, where an edge A -> B indicates that the type
variables in component A need to be solved before those in component
B.
3. Using the directed graph, compute the set of components that need
to be solved before a given component.
To utilize this, implement a new kind of solver step that handles the
propagation of partial solutions across one-way constraints. This
introduces a new kind of "split" within a connected component, where
we collect each combination of partial solutions for the input
components and (separately) try to solve the constraints in this
component. Any correct solution from any of these attempts will then
be recorded as a (partial) solution for this component.
For example, consider:
let _: Int8 = b ? Builtin.one_way(int8Or16(17)) :
Builtin.one_way(int8Or16(42\
))
where int8Or16 is overloaded with types `(Int8) -> Int8` and
`(Int16) -> Int16`. There are two one-way components (`int8Or16(17)`)
and (`int8Or16(42)`), each of which can produce a value of type `Int8`
or `Int16`. Those two components will be solved independently, and the
partial solutions for each will be fed into the component that
evaluates the ternary operator. There are four ways to attempt that
evaluation:
```
[Int8, Int8]
[Int8, Int16]
[Int16, Int8]
[Int16, Int16]
To test this, introduce a new expression builtin `Builtin.one_way(x)` that
introduces a one-way expression constraint binding the result of the
expression 'x'. The builtin is meant to be used for testing purposes,
and the one-way constraint expression itself can be synthesized by the
type checker to introduce one-way constraints later on.
Of these two, there are only two (partial) solutions that can work at
all, because the types in the ternary operator need a common
supertype:
[Int8, Int8]
[Int16, Int16]
Therefore, these are the partial solutions that will be considered the
results of the component containing the ternary expression. Note that
only one of them meets the final constraint (convertibility to
`Int8`), so the expression is well-formed.
Part of rdar://problem/50150793.
