It was originally introduced as an upcoming feature, but there isn't any
precedent for using upcoming features as a way to opt-in to type checking fixes
without an associated Swift Evolution proposal. Rather than using a "feature" to
control this behavior, it would probably be better to offer a way to use
`-Werror` to upgrade these warnings to errors.
A requirement defines the maximal effects that a witness can have.
In some cases, we'd fail to properly reject such a witness with more
effects, when that witness is valid for another requirement within that
protocol. Thus, we'd hit an assertion failure in that case rather than
permitting the valid program to compile.
In a non-asserts compiler, we could end up failing to diagnose an invalid
chosen witness and crash in IRGen.
https://github.com/apple/swift/issues/73479
rdar://127669069
This change forces you to write ``@reparented` relationships
on an extension of a protocol, rather than on the protocol
itself.
The ProtocolConformance needs to be associated with some
GenericContext and IRGen expects it to be an ExtensionDecl.
That environment defines under what conditions the conformance
exists. We also need to define witnesses for the new parent's
requirements in an extension anyway, so it's a natural fit.
The previous workaround for this was kind of awful, as it'd
require searching all the protocol's extensions and "guess"
which extension they want to represent the conformance. While
we could try to synthesize an extension, there's two
challenges there:
1. Due to SuppressedAssociatedTypes, it's not so simple to
synthesize an unconstrained ExtensionDecl.
2. We currently rely on same-type requirements to pin the
associated types to particular witnesses of those requirements
in the extension. So it's not purely unconstrained! For example,
```
extension Seq: @reparented BorrowSeq where Iter == MyIter {}
```
The constraints that are disallowed (but not yet diagnosed)
are conditional conformance requirements, as the default
conformance for a reparenting cannot depend on those.
Thus, it's better that programmers to specify the extension.
This does not rename all the internal variables, functions, and types
whose names were based on the old syntax.
I think it adds new syntax support everywhere it's needed while
retaining enough of the old syntax support that early adopters will
see nice deprecation messages guiding them to the new syntax.
Private member witnessing a public constraint should be deprecated.
Previously existing workaround is checked and compiler emits a warning
when strict access check is not passed. Test files were fixed to expect
the corresponding warning.
rdar://74904373
This helps avoid producing more downstream errors. This changes
`GenericSignature::forInvalid` to produce the same signature as e.g
`<T where T == Undefined>`. This subsumes the need to introduce
conformance requirements for invertible protocols.
This adds the -verify-ignore-unrelated flag. When -verify is used without -verify-ignore-unrelated, diagnostics emitted in buffers other than the main file and those passed with -verify-additional-file (except diagnostics emitted at <unknown>:0) will now result in an error. They were previously ignored. The old behaviour is still available as opt-in using -verify-ignore-unrelated, but by being strict by default it should make it harder to accidentally miss diagnostics.
To avoid unnecessary performance overhead, -verify-additional-file is still required to parse the expected-* directives in files other than the main file.
These are tests that fail in the next commit without this flag. This
does not add -verify-ignore-unrelated to all tests with -verify, only
the ones that would fail without it. This is NFC since this flag is
currently a no-op.
Move the logic from `FailureDiagnostic::resolveType` into
`Solution::simplifyType` to allow completion to use it too. While
here, also handle cases where the placeholder is from a different
member of the equivalence class to the generic parameter.
This is a diagnostic that is only really emitted as a fallback when
the constraint system isn't able to better diagnose the expression.
It's not particulary helpful for the user, and can be often be
misleading since the underlying issue might not actually be an
ambiguity, and the user may well already have a type annotation. Let's
instead just emit the fallback diagnostic that we emit in all other
cases, asking the user to file a bug.
The bug tracked by rdar://158172056 was already fixed by
https://github.com/swiftlang/swift/pull/83607 but this additional test case is
needed to ensure that conformances to Obj-C protocols with obsolete
requirements imported under legacy spellings not regress again.
The previous message was just suggesting unchecked Sendable, but instead
we should be suggesting to add final to the class. We also don't
outright suggest using unchecked Sendable -- following
https://github.com/swiftlang/swift/pull/81738 precedent.
Resolves rdar://155790695
This check had two problems. First, it would assert upon encountering
a layout requirement, due to an unimplemented code path.
A more fundamental issue is that the logic wasn't fully sound, because
it would miss certain cases, for example:
protocol P {
associatedtype A
func run<B: Equatable>(_: B) where B == Self.A
}
Here, the reduced type of `Self.A` is `B`, and at first glance, the
requirement `B: Equatable` appears to be fine. However, this
is actually a new requirement on `Self`, and the protocol be rejected.
Now that we can change the reduction order by assigning weights to
generic parameters, this check can be implemented in a better way,
by building a new generic signature first, where all generic
parameters introduced by the protocol method, like 'B' above, are
assigned a non-zero weight.
With this reduction order, any type that is equivalent to
a member type of `Self` will have a reduced type rooted in `Self`,
at which point the previous syntactic check becomes sound.
Since this may cause us to reject code we accepted previously,
the type checker now performs the check once: first on the original
signature, which may miss certain cases, and then again on the new
signature built with the weighted reduction order.
If the first check fails, we diagnose an error. If the second
check fails, we only diagnose a warning.
However, this warning will become an error soon, and it really
can cause compiler crashes and miscompiles to have a malformed
protocol like this.
Fixes rdar://116938972.
The concrete nesting limit, which defaults to 30, catches
things like A == G<A>. However, with something like
A == (A, A), you end up with an exponential problem size
before you hit the limit.
Add two new limits.
The first is the total size of the concrete type, counting
all leaves, which defaults to 4000. It can be set with the
-requirement-machine-max-concrete-size= frontend flag.
The second avoids an assertion in addTypeDifference() which
can be hit if a certain counter overflows before any other
limit is breached. This also defaults to 4000 and can be set
with the -requirement-machine-max-type-differences= frontend flag.
Evaluating LifetimeDependence changes the order that the declarations are
diagnosed. Fix this test output by flipping the order of two declarations. The
new order actually makes more sense to me.
In b30006837e, I changed the `if`
condition here to check for the absence of type variables as well
as type parameters. This is incorrect; the type variables come up
in ValueWitnessRequest, and the type parameters come up in
associated type inference. We want the matching to be more lax
in the former case.
Fixes rdar://149438520.
When generating a stub fix-it for a protocol conformance or implementation extension, Swift will now evaluate whether the context allows the declaration of stored properties and, if so, will suggest one. It will also use the `let` keyword instead of `var` if the property has no setter.
Changes the diagnostics emitted when an `@objc @implementation` extension is missing some of the members required by the extension:
• We now emit one error on the extension, plus a note for each missing member.
• Where possible, we also emit a note with a fix-it adding stubs.
For example:
```
9 | @objc @implementation extension ObjCClass {
| |- error: extension for main class interface does not provide all required implementations
| |- note: missing instance method 'method(fromHeader3:)'
| |- note: missing instance method 'method(fromHeader4:)'
| |- note: missing property 'propertyFromHeader7'
| |- note: missing property 'propertyFromHeader8'
| |- note: missing property 'propertyFromHeader9'
| |- note: missing instance method 'extensionMethod(fromHeader2:)'
| `- note: add stubs for missing '@implementation' requirements
```
With a fix-it on the last note to insert the following after the open brace:
```
@objc(methodFromHeader3:)
open func method(fromHeader3 param: Int32) {
<#code#>
}
@objc(methodFromHeader4:)
open func method(fromHeader4 param: Int32) {
<#code#>
}
@objc(propertyFromHeader7)
open var propertyFromHeader7: Int32 {
get {
<#code#>
}
set {
<#code#>
}
}
@objc(propertyFromHeader8)
open var propertyFromHeader8: Int32 {
get {
<#code#>
}
set {
<#code#>
}
}
@objc(propertyFromHeader9)
open var propertyFromHeader9: Int32 {
get {
<#code#>
}
set {
<#code#>
}
}
@objc(extensionMethodFromHeader2:)
open func extensionMethod(fromHeader2 param: Int32) {
<#code#>
}
```
Fixes rdar://130038221.
Print diagnostic groups as part of the LLVM printer in the same manner as the
Swift one does, always. Make `-print-diagnostic-groups` an inert option, since we
always print diagnostic group names with the `[#GroupName]` syntax.
As part of this, we no longer render the diagnostic group name as part
of the diagnostic *text*, instead leaving it up to the diagnostic
renderer to handle the category appropriately. Update all of the tests
that were depending on `-print-diagnostic-groups` putting it into the
text to instead use the `{{documentation-file=<file name>}}`
diagnostic verification syntax.
A protocol conformance can be ill-formed due to isolation mismatches
between witnesses and requirements, or with associated conformances.
Previously, such failures would be emitted as a number of separate
errors (downgraded to warnings in Swift 5), one for each witness and
potentially an extra for associated conformances. The rest was a
potential flood of diagnostics that was hard to sort through.
Collect all of the isolation-related problems for a given conformance
together and produce a single error (downgraded to a warning when
appropriate) that describes the overall issue. That error will have up
to three notes suggesting specific courses of action:
* Isolating the conformance (when the experimental feature is enabled)
* Marking the witnesses as 'nonisolated' where needed
*
The diagnostic also has notes to point out the witnesses/associated
conformances that have isolation problems. There is a new educational
note that also describes these options.
We give the same treatment to missing 'distributed' on witnesses to a
distributed protocol.
When diagnosing an isolation mismatch between a requirement and witness,
we would produce notes on the requirement itself suggesting the addition of
`async`. This is almost never what you want to do, and is often so far
away from the actual conforming type as to be useless. Remove this note,
and the non-function fallback that just points at the requirement, because
they are unhelpful.
This is staging for a rework of the way we deal with conformance-level
actor isolation problems.
The attribute makes the declaration unavailable from the perspective of clients
of the module's public interface and was creating a loophole that admitted
inappropriate unavailability.
Implement lookup of availability domains for identifiers on
`AvailabilityDomainOrIdentifier`. Add a bit to that type which represents
whether or not lookup has already been attempted. This allows both
`AvailableAttr` and `AvailabilitySpec` to share a common implementation of
domain lookup.
Aidan Hall
Aidan Hall
Meghana Gupta
Meghana Gupta
Allan Shortlidge
Kavon Farvardin
Sam Pyankov
Tim Kientzle
Xi Ge
Jamie
Slava Pestov
Hamish Knight
Henrik G. Olsson
Henrik G. Olsson
Konrad 'ktoso' Malawski
Andrew Trick
Anthony Latsis
Becca Royal-Gordon
Doug Gregor