`SyntacticElement` represents a statement, pattern, declaration,
condition, or expression and could originate from i.e. a closure,
a function or a result builder body.
In order to fit with the new IUO model where
functions with IUO results have the disjunction
formed when matching result types, we need to
update this logic to form applicable fn
constraints for the implicit `x[dynamicMember:]`
subscript call.
This is done using a new ImplicitDynamicMemberSubscript
locator path element to allow easy identification of
what the right callee and argument list should be.
Use this new element to represent the overload type
for a constructor call, and have it store a bit
indicating whether the call is for a short-form
`X(...)` or self-delegating `self.init(...)` call.
* [TypeResolver][TypeChecker] Add support for structural opaque result types
* [TypeResolver][TypeChecker] Clean up changes that add structural opaque result types
One can convert from a function value without a global actor to a
similar function type that does have a global actor, but one cannot
remove or change a global actor on a function type.
New name is `isInKeyPathComponent` since it's implemeneted as a
check for presence of `KeyPathComponent` element in the locator
that covers every sub-element contained in a key path component
as well.
Introduce `@concurrent` attribute on function types, including:
* Parsing as a type attribute
* (De-/re-/)mangling for concurrent function types
* Implicit conversion from @concurrent to non-@concurrent
- (De-)serialization for concurrent function types
- AST printing and dumping support
Records protocol requirement associated with a particular type in
the constraint system, also useful to track parent conformance
for conditional requirements.
It was used for unresolved member and `.dynamicType` references
as well as a couple of other places, but now unresolved member
references no longer need that due to new implicit "chain result"
AST node and other places could use more precise locators
e.g. new `.dynamicType` locator or `sequence element` for `for in`
loops.
`ArgumentAttribute` points to a particular attribute associated
with one of the arguments e.g. `inout` or its type e.g. `@escaping`.
This is very useful when dealing with argument-to-parameter
failures because it allows to express in the locator kind
of a problem.
Extend the constraint system’s diagnostics with specific handling for
matching an enum element pattern that has a subpattern (i.e., to capture
associated values) against an enum case that does not have any associated
value. This brings diagnostics for the new code path on par with the existing
diagnostics of coercePatternToType.
Generate a complete set of constraints for EnumElement patterns, e.g.,
case let .something(x, y)
Most of the complication here comes from the implicit injection of optionals,
e.g., this case can be matched to an optional of the enum type of which
`something` is a member. To effect this change, introduce a locator for
pattern matching and use it to permit implicit unwrapping during member
lookup without triggering an error.
Note also labels are dropped completely when performing the match,
because labels can be added or removed when pattern matching. Label
conflict are currently diagnosed as part of coercePatternToType, which
suffices so long as overloading cases based on argument labels is not
permitted.
The primary observable change from this commit is in diagnostics: rather
than diagnostics being triggered by `TypeChecker::coercePatternToType`,
diagnostics for matching failures here go through the diagnostics machinery
of the constraint solver. This is currently a regression, because
there are no custom diagnostics for pattern match failures within the
constraint system. This regression will be addressed in a subsequent
commit; for now, leave those tests failing.
Introduce a `ImplicitCallAsFunction` locator path
element to represent an implicit member reference
to `callAsFunction`. Then adjust CSApply a little
to check whether it's finishing an apply for a
callable type, and if so build the implicit member
access.
An awful pattern we use throughout the compiler is to save and restore global flags just for little things. In this case, it was just to turn on some extra options in AST printing for type variables. The kicker is that the ASTDumper doesn't even respect this flag. Add this as a PrintOption and remove the offending save-and-restores.
This doesn't quite get them all: we appear to have productized this pattern in the REPL.
Diagnose ephemeral conversions that are passed to @_nonEphemeral
parameters. Currently, this defaults to a warning with a frontend flag
to upgrade to an error. Hopefully this will become an error by default
in a future language version.
