This reverts commit 3e932c075d.
The compiler does not support @_alwaysEmitIntoClient properties
specially wrt property descriptors. The revert commit would introduce an
ABI incompatability when a keypath to Array.first is formed:
let greetings = ["hello", "hola"]
let count = greetings[keyPath: \[String].first?.count]
Runmning on an older runtime would lead to linker errors against $sSa5firstxSgvpMV
the property descriptor for Array.first.
rdar://58484319
This makes Array.first much small and more efficient.
Without this, Array.first compiled down to RandomAccessCollection.first, which ended up in pretty unefficient code.
rdar://problem/46291397
Existence of semantic expr (`getSemanticExpr()`) prevents ASTWalker
walking into the *original* sub expressions which may cause
re-typechecking failure. For example,
`ConstraintGenerator::visitArrayExpr()` assumes we already visited its
elements, but that's not the case if the semantic expr exists.
rdar://problem/42639255
There was a ton of complicated logic here to work around
two problems:
- Same-type constraints were not represented properly in
RequirementReprs, requiring us to store them in strong form
and parse them out when printing type interfaces.
- The TypeBase::getAllGenericArgs() method did not do the
right thing for members of protocols and protocol extensions,
and so instead of simple calls to Type::subst(), we had
an elaborate 'ArchetypeTransformer' abstraction repeated
in two places.
Rewrite this code to use GenericSignatures and
GenericFunctionType instead of old-school GenericParamLists
and PolymorphicFunctionType.
This changes the code completion and AST printer output
slightly. A few of the changes are actually fixes for cases
where the old code didn't handle substitutions properly.
A few others are subjective, for example a generic parameter
list of the form <T : Proto> now prints as <T where T : Proto>.
We can add heuristics to make the output whatever we want
here; the important thing is that now we're using modern
abstractions.
This fixes several issues:
- By default parent types of alias types are not printed which results in
- Erroneous fixits, for example when casting to 'Notification.Name' from a string, which ends up adding erroneous cast
as "Name(rawValue: ...)"
- Hard to understand types in code-completion results and diagnostics
- When printing with 'fully-qualified' option typealias types are printed erroneously like this "<PARENT>.Type.<TYPEALIAS>"
The change make typealias printing same as nominal types and addresses the above.
change includes both the necessary protocol updates and the deprecation
warnings
suitable for migration. A future patch will remove the renamings and
make this
a hard error.
The brief explanation is that we are using the type-checker in a
questionable way where for various reasons we can type-check the same
"context" expression more than once. Until we figure out how to stop
doing that, at least avoid this obvious source of issues with ErrorType
showing up during the initial (poor) typecheck and then blocking
progress when we do a more specific check later.
rdar://problem/26462306
rdar://problem/25248190
This covers:
- Lifetime-extending wrappers, like withExtendedLifetime, withCString, and withUnsafe*Pointer
- 'map' and friends on Optional
- 'indexOf'
A few APIs I haven't gotten to yet in this first pass:
- Autoclosure APIs, like assert, &&, etc.
- the 'isOrderedBefore' predicate for sorting APIs. The sorting implementation does some microoptimizations with 'inout' closures that violate rethrows checking.
- Strict 'map', 'filter', and friends on CollectionType. These need some plumbing in Lazy to be able to thread a Result-forming transformation through.
This version of the patch updates some protocol customization implementations that I missed the first time around, and includes the tests I forgot to add in the previous iteration.
Swift SVN r30790
This covers:
- Lifetime-extending wrappers, like withExtendedLifetime, withCString, and withUnsafe*Pointer
- 'map' and friends on Optional
- 'indexOf'
A few APIs I haven't gotten to yet in this first pass:
- Autoclosure APIs, like assert, &&, etc.
- the 'isOrderedBefore' predicate for sorting APIs. The sorting implementation does some microoptimizations with 'inout' closures that violate rethrows checking.
- Strict 'map', 'filter', and friends on CollectionType. These need some plumbing in Lazy to be able to thread a Result-forming transformation through.
Swift SVN r30597
<rdar://20494686>
String itsef should only expose Unicode-correct algorithms, like proper
substring/prefix/suffix search, enumerating words/lines/paragraphs, case
folding etc. Promoting sequence-centric algorithms to methods on String
is not acceptable since it invites users to write wrong code. Thus,
String has to lose its SequenceType conformance.
Nevertheless, we recognize that sometimes it is useful to manipulate the
String contents on lower levels (UTF-8, UTF-16, Unicode scalars,
extended grapheme clusters), for example, when implementing high-level
Unicode operations, so we can't remove low-level operations
altogether. For this reason, String provides nested "views" for the
first three low-level representations, but grapheme clusters were in a
privileged position -- String itself is a collection of grapheme
clusters. We propose to add a characters view that will represent the
String as a collection of Character values.
Swift SVN r28065
When we check a protocol conformance, we recurse to check the implied
protocol conformances for inherited protocols first. When doing so, we
were passing down the current DeclContext, which would force the
creation of a new conformance to that protocol within that
DeclContext. This isn't what we want: we want to find or create the
conformance in whichever context it naturally belongs.
This is a partial step toward solving the problem, which eliminates
the duplicate witness tables from the example in
rdar://problem/18182969. However, we're still not using the
conformance lookup table to decide where the witness tables/protocol
conformances go, which means the actual declaration context for a
witness table is still a bit ad hoc.
Baby steps.
Swift SVN r26129
When code completing a literal expr, it is likely that code completion engine only collects the expr
that is not fully type checked. Therefore, no members of the literal can be suggested. To address this,
we try to climb up expr hierarchy in AST to find an expr with a nominal type, and use the nominal type
to finish code completion.
rdar://20059173
Swift SVN r26116
