It's possible that getSuperclassDecl() returns something but
getSuperclass() does not, for example if you reference a generic
superclass with missing or invalid generic arguments. We would
crash in that case when going down this particular code path.
However, the call to getSuperclass() and the entire function it
appeared in was actually unnecessary.
Fixes https://github.com/swiftlang/swift/issues/74651
Fixes rdar://problem/130394943
First, if the base parameter is inout or vararg, the derived parameter
must be too. Second, we do not allow covariant overrides of inout or
vararg parameters.
Fixes <https://bugs.swift.org/browse/SR-10231>.
This makes diagnostics more verbose and accurate, because
it's possible to distinguish how many parameters there are
based on the message itself.
Also there are multiple diagnostic messages in a format of
`<descriptive-kind> <decl-name> ...` that get printed as
e.g. `subscript 'subscript'` if empty labels are omitted.
Stop creating ImplicitlyUnwrappedOptional<T> so that we can remove it
from the type system.
Enable the code that generates disjunctions for Optional<T> and
rewrites expressions based on the original declared type being 'T!'.
Most of the changes supporting this were previously merged to master,
but some things were difficult to merge to master without actually
removing IUOs from the type system:
- Dynamic member lookup and dynamic subscripting
- Changes to ensure the bridging peephole still works
Past commits have attempted to retain as much fidelity with how we
were printing things as possible. There are some cases where we still
are not printing things the same way:
- In diagnostics we will print '?' rather than '!'
- Some SourceKit and Code Completion output where we print a Type
rather than Decl.
Things like module printing via swift-ide-test attempt to print '!'
any place that we now have Optional types that were declared as IUOs.
There are some diagnostics regressions related to the fact that we can
no longer "look through" IUOs. For the same reason some output and
functionality changes in Code Completion. I have an idea of how we can
restore these, and have opened a bug to investigate doing so.
There are some small source compatibility breaks that result from
this change:
- Results of dynamic lookup that are themselves declared IUO can in
rare circumstances be inferred differently. This shows up in
test/ClangImporter/objc_parse.swift, where we have
var optStr = obj.nsstringProperty
Rather than inferring optStr to be 'String!?', we now infer this to
be 'String??', which is in line with the expectations of SE-0054.
The fact that we were only inferring the outermost IUO to be an
Optional in Swift 4 was a result of the incomplete implementation of
SE-0054 as opposed to a particular design. This should rarely cause
problems since in the common-case of actually using the property rather
than just assigning it to a value with inferred type, we will behave
the same way.
- Overloading functions with inout parameters strictly by a difference
in optionality (i.e. Optional<T> vs. ImplicitlyUnwrappedOptional<T>)
will result in an error rather than the diagnostic that was added
in Swift 4.1.
- Any place where '!' was being used where it wasn't supposed to be
allowed by SE-0054 will now treat the '!' as if it were '?'.
Swift 4.1 generates warnings for these saying that putting '!'
in that location is deprecated. These locations include for example
typealiases or any place where '!' is nested in another type like
`Int!?` or `[Int!]`.
This commit effectively means ImplicitlyUnwrappedOptional<T> is no
longer part of the type system, although I haven't actually removed
all of the code dealing with it yet.
ImplicitlyUnwrappedOptional<T> is is dead, long live implicitly
unwrapped Optional<T>!
Resolves rdar://problem/33272674.
For Swift 3 / 4:
Deprecate the spelling "ImplicitlyUnwrappedOptional", emitting a warning
and suggesting "!" in places where they are allowed according to
SE-0054.
In places where SE-0054 disallowed IUOs but we continued to accept them
in previous compilers, emit a warning suggesting "Optional" or "?" as
an alternative depending on context and treat the IUO as an Optional,
noting this in the diagnostic.
For Swift 5:
Treat "ImplicitlyUnwrappedOptional" as an error, suggesting
"!" in places where they are allowed by SE-0054.
In places where SE-0054 disallowed IUOs, emit an error suggestion
"Optional" or "?" as an alternative depending on context.
Per SE-0054, implicitly unwrapped optional is not a distinct type in the
type system, but rather just the notion that certain Optionals (denoted
by the sigil "!" rather than "?") can be implicitly unwrapped.
This is a first step in the direction of implementing this notion by
emitting a warning if the type is spelled out.
We were checking the accessibility of the setter incorrectly.
As a result, a 'public internal(set)' property could not override
another 'public internal(set)' property; the setter had to be
public in the override, which is unnecessarily visible.
Fixes <rdar://problem/34085586>.
In today's Swift, only non-optional function parameters can be
non-escaping (and are by default). An optional function parameter uses
a function type as a generic argument to Optional, and like any other
generics that's considered an opaque and therefore possibly escaping
use of the type. This is certainly unfortunate since it means a
function parameter cannot be both Optional and non-escaping.
However, this "unfortunate" becomes a concrete problem when dealing
with Objective-C, which /does/ allow applying its 'noescape' attribute
to a callback block marked 'nullable'. This is fine for /uses/ of
methods with such parameters, but prevents anyone from /overriding/
these methods.
This patch pokes a very narrow hole into the override checking to
accomodate this: if a declaration comes from Objective-C, and it has
an optional, non-escaping closure parameter, it's okay to override it
in Swift with an optional, escaping closure parameter. This isn't
strictly safe because a caller could be relying on the
non-escaping-ness, but we don't have anything better for now. (This
behavior will probably be deprecated in the future.)
(Some people have noted that the old 'noescape' type attribute in
Swift still works, albeit with a warning. That's not something people
should have to type, though---we want to remove it from the language,
as described in SE-0103.)
rdar://problem/32903155
Using the attribute in this position is a relic from the Swift 2
days, and fixing it required letting invalid code fall through to
Sema instead of being diagnosed in Parse proper. Treat 'var'
in this position like 'let' by simply offering to remove it
instead of extracting it into a separate variable.
This at least emits notes when someone overrides something but
gets the types a little wrong (more than just mismatched optionals,
as handled in d669d152).
Part of rdar://problem/26183575
In many places, we're interested in whether a type with archetypes *might be* a superclass of another type with the right bindings, particularly in the optimizer. Provide a separate Type::isBindableToSuperclassOf method that performs this check. Use it in the devirtualizer to fix rdar://problem/24993618. Using it might unblock other places where the optimizer is conservative, but we can fix those separately.
<rdar://problem/15975935> warning that you can use 'let' not 'var'
<rdar://problem/18876585> Compiler should warn me if I set a parameter as 'var' but never modify it
<rdar://problem/17224539> QoI: warn about unused variables
This uses a simple pass in MiscDiagnostics that walks the body of an
AbstractFunctionDecl. This means that it doesn't warn about unused properties (etc),
but it captures a vast majority of the cases.
It also does not warn about unused parameters (as a policy decision) because it is too noisy,
there are a variety of other refinements that could be done as well, thoughts welcome.
Swift SVN r28412
If you want to make the parameter and argument label the same in
places where you don't get the argument label for free (i.e., the
first parameter of a function or a parameter of a subscript),
double-up the identifier:
func translate(dx dx: Int, dy: Int) { }
Make this a warning with Fix-Its to ease migration. Part of
rdar://problem/17218256.
Swift SVN r27715
Most tests were using %swift or similar substitutions, which did not
include the target triple and SDK. The driver was defaulting to the
host OS. Thus, we could not run the tests when the standard library was
not built for OS X.
Swift SVN r24504
Also warn when the subclass returns 'T!' where the superclass returns 'T?'.
In both cases, allow silencing by wrapping the 'T!' in parentheses.
This is intended to provide migration help as Objective-C classes get
annotated for nullability. Because of that, the check is only run on @objc
classes, though it's not limited to classes that actually come from Objective-C
because of (a) deep subclass chains that may all need updating, and (b) ease
of testing.
<rdar://problem/17892184>
Swift SVN r21001
