- adds a default implementation of Collection’s subscript(bounds: Range<_>)
with the most general signature possible
- it is marked unavailable in order to prevent the
infinite recursion bug reported in SR-14848
- Collections whose SubSequence is Slice<Self> still get the proper default, as intended.
Introduce checking of ConcurrentValue conformances:
- For structs, check that each stored property conforms to ConcurrentValue
- For enums, check that each associated value conforms to ConcurrentValue
- For classes, check that each stored property is immutable and conforms
to ConcurrentValue
Because all of the stored properties / associated values need to be
visible for this check to work, limit ConcurrentValue conformances to
be in the same source file as the type definition.
This checking can be disabled by conforming to a new marker protocol,
UnsafeConcurrentValue, that refines ConcurrentValue.
UnsafeConcurrentValue otherwise his no specific meaning. This allows
both "I know what I'm doing" for types that manage concurrent access
themselves as well as enabling retroactive conformance, both of which
are fundamentally unsafe but also quite necessary.
The bulk of this change ended up being to the standard library, because
all conformances of standard library types to the ConcurrentValue
protocol needed to be sunk down into the standard library so they
would benefit from the checking above. There were numerous little
mistakes in the initial pass through the stsandard library types that
have now been corrected.
Without this change, SILGen will crash when compiling a use of the
derived protocol's requirement: it will instead attempt to use
the base protocol's requirement, but the code will have been
type-checked incorrectly for that.
This has a potential for source-compatibility impact if anyone's
using explicit override checking for their protocol requirements:
reasonable idioms like overriding a mutating requirement with a
non-mutating one will no longer count as an override. However,
this is arguably a bug-fix, because the current designed intent
of protocol override checking is to not allow any differences in
type, even "covariant" changes like making a mutating requirement
non-mutating. Moreover, we believe explicit override checking in
protocols is quite uncommon, so the overall compatibility impact
will be low.
This also has a potential for ABI impact whenever something that
was once an override becomes a non-override and thus requires a
new entry. It might require a contrived test case to demonstrate
that while using the derived entry, but it's quite possible to
imagine a situation where the derived entry is not used directly
but nonetheless has ABI impact.
Furthermore, as part of developing this patch (earlier versions of
which used stricter rules in places), I discovered a number of
places where the standard library was unintentionally introducing
a new requirement in a derived protocol when it intended only to
guide associated type deduction. Fixing that (as I have in this
patch) *definitely* has ABI impact.
Most of the stdlib's properties don't need @_borrowed because they're
@inlinable, but I did find one place in an overlay where it's probably
sensible to make the operation use generalized accessors even if
they're resilient.
* [stdlib] Minor documentation revisions
* [docs] Convert 'nonoptional' to 'non-optional'
We're switching to 'non-optional' across the board, as the unhyphenated
form is too easy to read as 'no-noptional'.
Now that we have removed overriding protocol requirements from witness
tables, they no longer have any effect on the ABI. Replace the FIXME
(ABI) comments with normal FIXMEs: there is no more ABI work to do
here.
Add the `-warn-implicit-overrides` flag when building the standard library
and overlays, so that each protocol member that overrides a member of an
inherited protocol will produce a warning unless annotated with either
‘override’ or ‘@_nonoverride’.
An annotation of `override` will mean that the overriding requirement will be treated identically to the overridden declaration. If for some reason a concrete type’s conformance to the inheriting protocol provides a different witness for the overriding requirement than the conformance to the inherited protocol’s witness for the overridden requirement, the witness for the inheriting (more-specialized) protocol will be ignored. A protocol requirement marked ‘override’ only makes sense when the declaration is needed to help associated type inference, which is why the ‘override’ annotations correlate so closely with ABI FIXMEs.
An annotation of `@_nonoverride` means that the two protocol requirements will be treated independently, and may be bound to different witnesses. Use `@_nonoverride` when we might need different witnesses, e.g., because the semantics of the potentially-overriding declaration differ from that of the potentially-overridden declaration. `BidirectionalCollection.index(_:offsetBy:)` is the most obvious example, because the `BidirectionalCollection` ’s version of `index(_:offsetBy:)` allows negative indices. `RandomAccessCollection` ’s version is also marked `@_nonoverride` because it is required to be asymptotically faster than the `Collection` or `BidirectionalCollection` versions.
- Fix error in `last(where:)` example
- Improve MemoryLayout, UnsafePointer, and integer operator discussions
- Clean up ranges and random APIs
- Revisions to overflow operators and the SignedNumeric requirements
- Standardize on 'nonoptional' in remaining uses
* [stdlib] Update complexity docs for seq/collection algorithms
This corrects and standardizes the complexity documentation for Sequence
and Collection methods. The use of constants is more consistent, with `n`
equal to the length of the target collection, `m` equal to the length of
a collection passed in as a parameter, and `k` equal to any other passed
or calculated constant.
* Apply notes from @brentdax about complexity nomenclature
* Change `n` to `distance` in `index(_:offsetBy:)`
* Use equivalency language more places; sync across array types
* Use k instead of n for parameter names
* Slight changes to index(_:offsetBy:) discussion.
* Update tests with new parameter names
* Remove case destructuring to _
* Remove some Iterator.Element
* Which idiot wrote this? Oh.
* Switch NibbleSort to just use default impls... shouldn't change perf
We would like to eventually extend Array, Dictionary, and Set to support move-only element types when the language does. To that end, we need to get the `consuming`-ness of protocol requirements on Sequence, Collection, and related protocols right for forward compatibility so that a future version of Swift that extends these types to support move-only data structures remains ABI- and API-compatible with older versions of the language. Mark requirements as `__consuming` where it would be necessary for a move-only implementation of one of these types.
This includes various revisions to the APIs landing in Swift 4.2, including:
- Random and other randomness APIs
- Hashable changes
- MemoryLayout.offset(of:)
* Use the `__has_include` and `GRND_RANDOM` macros
* Use `getentropy` instead of `getrandom`
* Use `std::min` from the <algorithm> header
* Move `#if` out of the `_stdlib_random` function
* Use `getrandom` with "/dev/urandom" fallback
* Use `#pragma comment` to import "Bcrypt.lib"
* <https://docs.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp>
* <https://clang.llvm.org/docs/UsersManual.html#microsoft-extensions>
* Use "/dev/urandom" instead of `SecRandomCopyBytes`
* Use `swift::StaticMutex` for shared "/dev/urandom"
* Add `getrandom_available`; use `O_CLOEXEC` flag
Add platform impl docs
Update copyrights
Fix docs
Add _stdlib_random test
Update _stdlib_random test
Add missing &
Notice about _stdlib_random
Fix docs
Guard on upperBound = 0
Test full range of 8 bit integers
Remove some gyb
Clean up integerRangeTest
Remove FixedWidthInteger constraint
Use arc4random universally
Fix randomElement
Constrain shuffle to RandomAccessCollection
warning instead of error
Move Apple's implementation
Fix failing test on 32 bit systems
* [stdlib] Revise documentation for new random APIs
* [stdlib] Fix constraints on random integer generation
* [test] Isolate failing Random test
* [benchmark] Add benchmarks for new random APIs
Fix Float80 test
Value type generators
random -> randomElement
Fix some docs
One more doc fix
Doc fixes & bool fix
Use computed over explicit
* Remove refs to Countable ranges
* Add `_stdlib_random` for more platforms
* Use `getrandom` (if available) for Android, Cygwin
* Reorder the `_stdlib_random` functions
* Also include <features.h> on Linux
* Add `#error TODO` in `_stdlib_random` for Windows
* Colon after Fatal Error
Performance improvement for Random
gybify ranges
Fix typo in 'basic random numbers'
Add _stdlib_random as a testable method
Switch to generic constraints
Hopefully link against bcrypt
Fix some implementation details
1. Uniform distribution is now uniform
2. Apply Jens' method for uniform floats
Fix a lineable attribute
Initial random api
Use C syscall for I/O
1. Fixed an issue where integers would would result in an infinite loop if they were unsigned, or signed integers always returning negative numbers.
2. Fixed an issue with Bool initialization
Add shuffle functions
Add documentation to Random API
Fix a few typos within the documentation
Fixes more typos
Also states that the range for floating points is from 0 to 1 inclusive
Update API to reflect mailing list discussions
Remove unnecessary import
Make sure not to return upperBound on Range
Use SecRandomCopyBytes on older macOS
Update API to match mailing list discussion, add tests
Added pick(_:) to collection
Added random(in:using:) to Randomizable
Added tests
Fix typo in Randomizable documentation
Rename pick to sampling
Move sampling below random
Update docs
Use new Libc naming
Fix Random.swift with new Libc naming
Remove sampling
gybify signed integer creation
Make FloatingPoint.random exclusive
Refactor {Closed}Range.random
Fix FloatingPoint initialization
Precondition getting a random number from range
Fix some doc typos
Make .random a function
Update API to reflect discussion
Make .random a function
Remove .random() in favor of .random(in:) for all numeric types
Fix compile errors
Clean up _stdlib_random
Cleanup around API
Remove `.random()` requirement from `Collection`
Use generators
Optimize shuffle()
Thread safety for /dev/urandom
Remove {Closed}Range<BinaryFloatingPoint>.random()
Add Collection random requirement
Refactor _stdlib_random
Remove whitespace changes
Clean linux shim
Add shuffle and more tests
Provide finishing tests and suggestions
Remove refs to Countable ranges
Revert to checking if T is > UInt64
This implements the new last(where:), and lastIndex(of/where:) methods as
extensions on `BidirectionalCollection`, which partially implements SE-204.
The protocol requirements for `Sequence` and `Collection` as described
in the proposal need to wait until there's a solution for picking up the
specialized versions in types that conditionally conform to `BidirectionalCollection`.
