This reverts commit
ecfa406fc5, which was reinstating
3c5b393e0c.
It does not revert one test change from that commit, because
inexplicably one of the tests is still failing, probably due to some
other changes that have happened since. I'm leaving a ticket open to
investigate.
I've added one of the new cases that is failing as a result of this
change.
This is being reverted not because of bugs in this particular commit,
but because it seems to be exposing other bugs in the type checker that
are resulting in source compatibility problems. We need to shake these
other bugs out of the type checker before bringing this change back.
* Give Sequence a top-level Element, constrain Iterator to match
* Remove many instances of Iterator.
* Fixed various hard-coded tests
* XFAIL a few tests that need further investigation
* Change assoc type for arrayLiteralConvertible
* Mop up remaining "better expressed as a where clause" warnings
* Fix UnicodeDecoders prototype test
* Fix UIntBuffer
* Fix hard-coded Element identifier in CSDiag
* Fix up more tests
* Account for flatMap changes
Like NSObject, CFType has primitive operations CFEqual and CFHash,
so Swift should allow those types to show up in Hashable positions
(like dictionaries). The most general way to do this was to
introduce a new protocol, _CFObject, and then have the importer
automatically make all CF types conform to it.
This did require one additional change: the == implementation that
calls through to CFEqual is in a new CoreFoundation overlay, but the
conformance is in the underlying Clang module. Therefore, operator
lookup for conformances has been changed to look in the overlay for
an imported declaration (if there is one).
This re-applies 361ab62454, reverted in
f50b1e73dc, after a /very/ long interval
where we decided if it was worth breaking people who've added these
conformances on their own. Since the workaround isn't too difficult---
use `#if swift(>=3.2)` to guard the extension introducing the
conformance---it was deemed acceptable.
https://bugs.swift.org/browse/SR-2388
UnsafeBufferPoiunter subscript used in the fast path only checks bounds
in Debug mode, therefore extra checks are needed.
Addresses: <rdar://problem/31992473>
We previously used a simple heuristic of visiting the disjunction with
the fewest number of elements in it.
Instead, this commit introduces a new way to select the best disjunction
to explore based on attempting disjunctions based on either how much
information we have about the associated type variables (e.g. how many
of the arguments of a function call in the case of bind overload
disjunctions) or by other criteria that help constraint the search or
split the connected components (e.g. coercions and calls to
initializers).
A key part of the improvement here is allowing the type checker to
attempt bindings of types to type variables when there are still
argument conversion constraints between type variables in the
system. The insight here is if there are no other constraints blocking
an attempt to bind types and we have types to try, we will be able to
test those types against active conformance constraints and potentially
fail much earlier while solving.
Visiting disjunctions in a different order exposed some other problems
with the type checker including a couple cases where map is used that
are now considered ambiguous due to problems in how we are ranking
solutions.
I measured an 11-13% reduction in type checking time for the standard
library using a release build of the compiler.
A variety of enhancements from SE-154 and SE-165:
- Custom Keys and Values collections for Dictionary
- Two sequence-based Dictionary initializers
- Merging methods for Dictionary
- Capacity checking and reserving for Dictionary and Set
- Type-specific filter(_:) methods for Dictionary and Set
- A mapValues(_:) method for Dictionary
- A grouping Dictionary initializer
Eliminate the vestigial type `LazyFilterIndex`, which was
necessary pre-Swift-3 to allow the index to move. Swift 3's indexing
model means that the movement of indices is on the collection itself,
so we no longer need `LazyFilterIndex`: instead, the `Index` type of
the lazy filtered collection is simply the `Index` type of the base
collection, which is a nice convenience: it means you can take indices
from a lazy wrapper around a given collection C and use them with the
collection C (and, with care, vice-versa) without jumping through
extra hoops.
Address ABI FIXME #68 by using same-type constraints directly on an
associated type to describe the requirements on the Indices associated
type of the Collection protocol. ABI FIXMEs #89, #90, #91 are all in
StdlibUnittest, and provoke warnings once #68 is fixed, but it's nice
to clear them out.
Fixes SR-2121.
These had previously been removed in
9c2bc50acd because of differences in the
diagnostics being emitted across different platforms.
It looks like we're always emitting the same diagnostic now, so restore
a specific message.
Resolves: rdar://problem/19677545
