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
Top-level entry points fully testing a collection instance:
check${Traversal}Collection
One level of recursion into all slices of the collection instance
O(n^2). (Not combinatorial).
Previously, checkCollection() did nothing. So much of the testing infrastructure was inactive. Now it runs all forward collection tests.
Fixes a bug in subscriptRangeTests.
The UnsafeRawBufferPointer and Data collection testing is disabled and
will be fixed in the following commit.
* Add sliceability tests for Unsafe(Raw)BufferPointer.
Improve the generic sliceability tests to verify that SubSequence indices are
compatible with their parents indices.
* Fix and enable testing stdlib Collection instances.
Top-level entry points fully testing a collection instance:
check${Traversal}Collection
One level of recursion into all slices of the collection instance
O(n^2). (Not combinatorial).
Previously, checkCollection() did nothing. So much of the testing infrastructure was inactive. Now it runs all forward collection tests.
Fixes a bug in subscriptRangeTests.
The UnsafeRawBufferPointer and Data collection testing is disabled and
will be fixed in the following commit.
* Give UnsafeRawBufferPointer a distinct slice type.
SubSequence = RandomAccessSlice<Self>
* Fix raw buffer pointer tests after changing the API
* Add UnsafeRawBuffer(rebasing:) initializers.
Allows converting a raw slice into a zero-based raw buffer,
which is a common operation on flat memory.
Add and update UnsafeRawBufferPointer unit tests.
* Do not run recursive O(n^2) collection slice testing on large collections.
Now, even with collection unit testing wired up, the validation tests
take the same amount of time to execute.
* Add init(rebasing:) to UnsafeBufferPointer.
This is required for consistency with UnsafeRawBufferPointer.
* Update CHANGELOG.md for SE-0138 amendment: UnsafeRawBufferPointer slice type.
* IRGen: Change c-o-w existential implementation functions
* initialzeBufferWith(Copy|Take)OfBuffer value witness implementation for cow existentials
Implement and use initialzeBufferWith(Copy|Take)OfBuffer value witnesses for
copy-on-write existentials.
Before we used a free standing function but the overhead of doing so was
noticable (~20-30%) on micro benchmarks.
* IRGen: Use common getCopyOutOfLineBoxPointerFunction
* Add a runtime function to conditionally make a box unique
* Fix compilation of HeapObject.cpp on i386
* Fix IRGen test case
* Fix test case for i386
Calling drop(while: ) after prefix() on a pure Sequence loses the
prefix, because in the internal drop(while: ) override grabs the
underlying base iterator from _PrefixSequence and wraps it in a
_DropWhileSequence.
