Currently, we don't have a fix-it to insert 'async', so I've marked those places
as not expecting a fix-it, until someone goes and implements that (rdar://72313654)
Let's consider conditional requirement failure to mean that parent
conformance requirement wasn't satisfied and nothing more, that helps
to disambiguate certain situations and avoid filtering out conditional
failures.
Resolves: rdar://problem/64844584
When an 'async let' initializer can throw, any access to one of the
variables in the 'async let' can also throw, so require such accesses
to be annotated with 'try'.
Customize diagnostics when an 'await' is missing in an 'async let'
initializer. While here, fix the coverage checking so we also diagnose
a missing 'try'.
The initializer of an 'async let' is executed as a separate child task
that will run concurrently with the main body of the function. Model
the semantics of this operation by wrapping the initializer in an
async, escaping autoclosure (representing the evaluation of the child
task), and then a call to that autoclosure (to
This is useful both for actor isolation checking, which needs to treat
the initializer as executing in concurrent code, and also (eventually)
for code generation, which needs to have that code in a closure so
that it can be passed off to the task-creation functions.
There are a number of issues with this implementation producing
extraneous diagnostics due to this closure transformation, which will
be addressed in a follow-up commit.
Extend effects checking to ensure that each reference to a variable
bound by an 'async let' is covered by an "await" expression and occurs
in a suitable context.
We need to preserve the DiagnoseErrorOnTry bit stored in the Context when
exiting a ContextScope. Otherwise, we fail to produce a diagnostic if the
'try' expression pushes an intertwining Context, such as a string interpolation
or 'await'.
Fixes <https://bugs.swift.org/browse/SR-13654>, <rdar://problem/69958774>.
Fix the parsing of await/try/try?/try! so that the two can be nested
(e.g., `await try f()` or `try await f()`).
Then, fix the effects checking logic to preserve all throws-related
information under an `await`, and preserve all async/await-related
information under `try`/`try?`/`try!`.
Add a number of tests, and fix 'await' handling for string
interpolations as well.
Allow async calls and await expressions within @asyncHandler functions.
If we see an async call or await expression in a function that is not
an async context, also suggest adding @asyncHandler if the function
meets the semantic constraints.
Replace the uglified '__await' keyword with a contextual keyword
'await'. This is more of what we would actually want for the
concurrency model.
When concurrency is enabled, this will be a source-breaking change,
because this is valid Swift code today:
```swift
struct MyFuture<T> {
func await() -> }
func doSomething() {
let result = await()
}
}
```
but the call to `await()` will be parsed as an await expression when
concurrency is enabled. The source break is behind the experimental
concurrency flag, but this way we can see how much of an issue it is
in practice.
Closurea can become 'async' in one of two ways:
* They can be explicitly marked 'async' prior to the 'in'
* They can be inferred as 'async' if they include 'await' in the body
Implement missing restrictions on calls to 'async':
* Diagnose async calls/uses of await in illegal contexts (such as
default arguments)
* Diagnose async calls/uses of await in functions/closures that are not
asynchronous themselves
* Handle autoclosure arguments as their own separate contexts (so
'await' has to go on the argument), which differs from error handling
(where the 'try' can go outside) because we want to be more particular
about marking the specific suspension points.
Similar to `try`, await expressions have no specific semantics of their
own except to indicate that the subexpression contains calls to `async`
functions, which are suspension points. In this design, there can be
multiple such calls within the subexpression of a given `await`.
Note that we currently use the keyword `__await` because `await` in
this position introduces grammatical ambiguities. We'll wait until
later to sort out the specific grammar we want and evaluate
source-compatibility tradeoffs. It's possible that this kind of prefix
operator isn't what we want anyway.
* [CSDiagnostics] Adjusting MemberAccessOnOptionalBaseFailure to be able to handle key path component member base types
* [tests] Adding regression tests for SR-5688
* [CSDiagnostics] Adjusting source range to diagnose/insert the fixes in correct location
* [tests] Adjusting regression tests to handle the fixits
* [AST] Creating an helper getSourceRange function for KeyPathExpr::Component
* [ConstraintSystem] Store member base type when recording UnwrapOptionalBase fix
* [AST] Creating a new diagnostic note for removing optional from written type
* [CSDiagnostics] Adjusting logic around MemberAccessOnOptionalBaseFailure to emit the correct diagnostics and fixes
* [tests] Adjusting regression tests to add subscript and key path root cases with respective diagnostics
* [Diagnostics] Adjusting message to mention base type
* [CSDiagnostics] Better naming for method/variable that represents base source range
* [CSDiagnostics] Adjusting to use the stored base member only when member is a key path component.
* [Diagnostics] Adjusting minor typos and code
* [AST] Adjusting keypath root diagnostic note message for use unwrapped type
* [CSDiagnostics] Adjusments in MemberAccessOnOptionalBaseFailure diagnostics as per suggestion
* [tests] Adding more test cases for SR-5688
* [CSDiagnostics] Adjusting fixits for key path root and range for diagnostics
* [CSSimplify] Attempt to diagnose InsertExplicitCall for optional function return types when possible on simplifyOptionalObjectConstraint
* [tests] Adding TODO to improve the diagnostics refering to key path root infered as optional types
* [CSDiagnostics] Adjusting comments
* [CSSimplify] Adjusting logic on simplifyOptionalObjectConstraint to attempt InsertCall fix before remove unwrap
* [CSDiagnostics] Adjust the logic to use resolveType on MemberAccessOnOptionalBaseFailure construction
Currently it's possible to have a type conflict between different
requirements deduced as the same type which leads to incorrect
diagnostics. To mitigate that let's adjust how "fixed" requirements
are stored - instead of using resolved type for the left-hand side,
let's use originating generic parameter type.
Instead of requiring sub-classes of `ContextualMismatch` to implement
`diagnoseForAmbiguity` let's implement it directly on `ContextualMismatch`
itself and check whether all of the aggregated fixes have same types on
both sides and if so, diagnose as-if it was a single fix.
We currently leave a key path constraint unsolved
if one of its components hasn't yet had its
overload resolved. However, for e.g a missing
member component, the overload type variable will
be bound to a hole and an overload will never be
resolved.
Tweak the logic to consider the key path constraint
trivially solved if one of its components has been
marked as a hole, which will allow the key path
type itself to be marked as a hole.
Resolves SR-12437 & SR-12823.
Resolves rdar://62201037.
Detect situation when it's impossible to determine types for
closure parameters used in the body from the context. E.g.
when a call closure is associated with refers to a missing
member.
```swift
struct S {
}
S.foo { a, b in } // `S` doesn't have static member `foo`
let _ = { v in } // not enough context to infer type of `v`
_ = .foo { v in } // base type for `.foo` couldn't be determined
```
Resolves: [SR-12815](https://bugs.swift.org/browse/SR-12815)
Resolves: rdar://problem/63230293
If a Swift key path has root type inferred but does not have a leading dot,
then diagnose it, because it's not valid.
For example:
```swift
struct Foo {
let property: [Int] = []
let kp: KeyPath<Foo, Int> = \property.count // error
}
```
Resolves SR-12290
Resolves rdar://problem/59874355
Previously we were bailing early on encountering
an optional chain in the key path. However this
could cause us to miss invalid components further
down the line. Instead, set a flag and force the
key path to be read-only if we encountered an
optional chain.
Resolves SR-12519.
