* Implement dynamically callable types (`@dynamicCallable`).
- Implement dynamically callable types as proposed in SE-0216.
- Dynamic calls are resolved based on call-site syntax.
- Use the `withArguments:` method if it's defined and there are no
keyword arguments.
- Otherwise, use the `withKeywordArguments:` method.
- Support multiple `dynamicallyCall` methods.
- This enables two scenarios:
- Overloaded `dynamicallyCall` methods on a single
`@dynamicCallable` type.
- Multiple `dynamicallyCall` methods from a `@dynamicCallable`
superclass or from `@dynamicCallable` protocols.
- Add `DynamicCallableApplicableFunction` constraint. This, used with
an overload set, is necessary to support multiple `dynamicallyCall`
methods.
Let's keep track of type mismatch between type deduced
for the body of the closure vs. what is requested
contextually, it makes it much easier to diagnose
problems like:
```swift
func foo(_: () -> Int) {}
foo { "hello" }
```
Because we can pin-point problematic area of the source
when the rest of the system is consistent.
Resolves: rdar://problem/40537960
If failed constraint mentions member declaration which is not
generic, it means that generic requirements came from context
and should not be diagnosed by `diagnoseUnresolvedDotExprTypeRequirementFailure`.
Resolved: rdar://problem/45511837
Arbitrary currying is no longer allowed so level could be switched
to a boolean flag for methods like `computeDefaultMap` to identify
if they need to look through curried self type or not.
Forming constraints instead of using `matchTypes` while matching argument/parameter
types makes sure that `failedConstraint` points to failed argument conversion
instead of `applicable function` constraint, which is better for diagnostics.
There's no need to instantiate archetypes in the generic environment
of the declaration being opened.
A couple of diagnostics changed. They were already misleading, and the
new diagnostics, while different, are not any more misleading than
before.
`\.self` is the final chosen syntax. Implement support for this syntax, and remove the stopgap builtin and `WritableKeyPath._identity` property that were in place before.
Previously we would generate the following constraint here, where
'index' and 'output' are concrete types and $input is a type
variable:
- ValueMember(base, $input -> output)
- ArgumentTupleConversion(index, $input)
The problem is that we built a function type where the entire input
was a type variable, which would then bind to an argument list.
We could instead generate this constraint:
- ValueMember(base, $member)
- ApplicableFunction(index -> output, $member)
I also had to redo how keypaths map locators back to key path
components. Previously the ArgumentTupleConversion was created
with a locator ending in KeyPathComponent.
Now the ApplicableFunction is created with this locator, which means
the argument match is performed with a locator ending in
ApplyArgument.
A consequence of this is that the SubscriptIndex and SubscriptResult
locator path elements are no longer used, so remove them.
This requires various mechanical changes in places we look at
locators to handle this change. Should be NFC.
We were building the following constraint, where $member and
$input are type variables and 'result' is a concrete type:
- Conversion($member, $input -> result)
When $member was fixed to a function type of arbitrary
arity, this would simplify to a conversion between $member's
result type and 'result'.
Instead, express this using the newly-added FunctionResult
constraint:
- FunctionResult($member, $result)
- Conversion($result, result)
I wasn't expecting this to change diagnostics, but it looks
like it did; I'm not going to bother investigating why,
because Pavel is going to rewrite contextual diagnostics soon
anyway. All but one are clear improvements.
Fixes <rdar://41416346> and <rdar://41416647>, two cases where
diagnostics regressed from -swift-version 3 to -swift-version 4.
Previously we would generate the following constraints here, where
'base', 'arg' and 'result' are concrete types, and $t is a type
variable:
- ValueMember(base, $t -> result)
- ArgumentTupleConversion(arg, $t)
Instead, we now generate these constraints:
- ValueMember(base, $method)
- ApplicableFunction(arg -> result, $method)
Recall that when the right hand side of an ApplicableFunction is
fixed, it simplifies down to an ArgumentTupleConversion and a
Bind. So the above formulation is equivalent, except that again,
we avoid forming a FunctionType where the entire input type is
a single type variable.
As with the UnresolvedDotExpr case, the old code set the
TVO_PreferSubtypeBinding flag on $t, so to preserve the old
ranking behavior, we generate an additional type variable and
constraint:
- FunctionInput($method, $arg)
This is just a temporary stop-gap until TVO_PreferSubtypeBinding
is removed.
Note that if the arguments to a constructor call are invalid, we
now fail the ApplicableFunction constraint and not a
ArgumentTupleConversion. This requires a minor change in CSDiag.
The whole concept of looking at the failed constraint is going
away hopefully, in favor of more precise TypeMatchResult and
Fix-based logic.
Merge logic from `diagnoseAssignmentFailure` and `diagnoseSubElementFailure`
into new `AssignmentFailure`, together with their support functions, which
decouples `CSDiagnostics` from `CSDiag` and scrubs latter from some functionality.
If all of the solutions in the set have a single fix, which points
to the common anchor, attempt to diagnose the failure as an
ambiguity with a list of candidates and their related problems as notes.
Having richer message like that helps to understand why something is
ambiguous e.g. if there are two overloads, one requires conformance
to some protocol and another has a same-type requirement on some type,
but neither matched exactly, having both candidates in the diagnostic
message with associated errors, instead of simplify pointing to related
declarations, helps tremendously.
This makes it easier to grep for and eventually remove the
remaining usages.
It also allows you to write FunctionType::get({}, ...) to call the
ArrayRef overload empty parameter list, instead of picking the Type
overload and calling it with an empty Type() value.
While I"m at it, in a few places instead of renaming just clean up
usages where it was completely mechanical to do so.
- getAsDeclOrDeclExtensionContext -> getAsDecl
This is basically the same as a dyn_cast, so it should use a 'getAs'
name like TypeBase does.
- getAsNominalTypeOrNominalTypeExtensionContext -> getSelfNominalTypeDecl
- getAsClassOrClassExtensionContext -> getSelfClassDecl
- getAsEnumOrEnumExtensionContext -> getSelfEnumDecl
- getAsStructOrStructExtensionContext -> getSelfStructDecl
- getAsProtocolOrProtocolExtensionContext -> getSelfProtocolDecl
- getAsTypeOrTypeExtensionContext -> getSelfTypeDecl (private)
These do /not/ return some form of 'this'; instead, they get the
extended types when 'this' is an extension. They started off life with
'is' names, which makes sense, but changed to this at some point. The
names I went with match up with getSelfInterfaceType and
getSelfTypeInContext, even though strictly speaking they're closer to
what getDeclaredInterfaceType does. But it didn't seem right to claim
that an extension "declares" the ClassDecl here.
- getAsProtocolExtensionContext -> getExtendedProtocolDecl
Like the above, this didn't return the ExtensionDecl; it returned its
extended type.
This entire commit is a mechanical change: find-and-replace, followed
by manual reformatted but no code changes.
Pass constraint system down into offering force unwrap fixits so that we can identify the type of the last member chosen for an optional chain. If there's a chain and the last member's return type isn't optional, then it's cleaner to offer to change that last '?' into a '!' to perform the force, rather than parenthesize the whole expression and force the result.
This is a legacy holdover from when tuple types had default
arguments, and also the constraint solver's matching of function
types pre-SE-0110.
Well, move the last live usage to CSDiag, where it can die a slow
painful death over time. The other usages were not doing anything.
Unresolved member calls e.g. `.foo(1, 2)` are unique in a way that
they don't form regular application expressions. So let's teach
`simplifyLocator` how to extract arguments from such calls
based on locators like:
`[UnresolvedMemberExpr -> apply argument -> comparing call argument # to parameter #]`.
This helps to diagnose more failures via diagnostics attached to
constraint system fixes.
This either became dead shortly after the removal of Swift 3
compatibility mode from the constraint solver, or even earlier.
Note that the code completion test change is actually correct
because (Any) -> () is not convertible to () -> () in the
language.
