Teach the constraint solver about the subtyping rule that permits
converting one function type to another when the effective thrown error
type of one is a subtype of the effective thrown error type of the
other, using `any Error` for untyped throws and `Never` for
non-throwing.
With minor other fixes, this allows us to use typed throws for generic
functions that carry a typed error from their arguments through to
themselves, which is in effect a typed `rethrows`:
```swift
func mapArray<T, U, E: Error>(_ array: [T], body: (T) throws(E) -> U)
throws(E) -> [U] {
var resultArray: [U] = .init()
for value in array {
resultArray.append(try body(value))
}
return resultArray
}
```
Conflict in CAS options when
`std::vector<std::string> CacheReplayPrefixMap;` was added.
Conflicts:
include/swift/Frontend/FrontendOptions.h
Resolution: Take both
Doing so fits better into conjunction model which leads to more
granular control over what variables are brought into scope during
`where` clause expression checking.
These changes also remove "one-way bind" flag from "for-in" statement
target.
Conflicts:
- `CMakeLists.txt` caused by the extra `-D` added in rebranch to
reduce the number of deprecation warnings.
- `lib/Frontend/PrintingDiagnosticConsumer.cpp` caused by the removal
of one of the `#if SWIFT_SWIFT_PARSER` on rebranch (probably should
have been done on main).
Allow DependencyScanner to canonicalize path using a prefix map. When
option `-scanner-prefix-map` option is used, dependency scanner will
remap all the input paths in following:
* all the paths in the CAS file system or clang include tree
* all the paths related to input on the command-line returned by scanner
This allows all the input paths to be canonicalized so cache key can be
computed reguardless of the exact on disk path.
The sourceFile field is not remapped so build system can track the exact
file as on the local file system.
From being a scattered collection of 'static' methods in ScanDependencies.cpp
and member methods of ASTContext. This makes 'ScanDependencies.cpp' much easier
to read, and abstracts the actual scanning logic away to a place with common
state which will make it easier to reason about in the future.
`lookupConformance` request is not cached and constraint solver
performs a lot of them for the same type (i.e. during disjunction
solving), let's try to cache previously performed requests to
see whether additional memory use is worth the performance benefit.
Augment the TypeVarRefCollector such that it
picks up any type variables present in the result
type for a closure DeclContext when visiting a
ReturnStmt. This ensures we correctly handle
if/switch expressions that contain `return`
statements.
rdar://114402042
These allow multi-statement `if`/`switch` expression
branches that can produce a value at the end by
saying `then <expr>`. This is gated behind
`-enable-experimental-feature ThenStatements`
pending evolution discussion.
`hasEmptyPath` in locator builder context means that there are
no new elements added which is different from the materialized
locator, `directlyAt` has to use `!last()` to check whether or
not there are any elements in the path of this builder.
Skip type-checking multi-statement branches if the
completion is in a single-expression branch, and
skip type-checking the expression as a whole if
the completion is in a multi-statement branch.
Move the contextual type locator onto
ContextualTypeInfo, and consolidate the separate
fields in SyntacticElementTarget into storing a
ContextualTypeInfo. This then lets us plumb down
the locator for the branch contextual type of an
if/switch expression from the initial constraint
generation, rather than introducing it later. This
should be NFC.
