<rdar://problem/46548531> Extend @available to support PackageDescription
This introduces a new private availability kind "_PackageDescription" to
allow availability testing by an arbitary version that can be passed
using a new command-line flag "-swiftpm-manifest-version". The semantics
are exactly same as Swift version specific availability. In longer term,
it maybe possible to remove this enhancement once there is
a language-level availability support for 3rd party libraries.
Motivation:
Swift packages are configured using a Package.swift manifest file. The
manifest file uses a library called PackageDescription, which contains
various settings that can be configured for a package. The new additions
in the PackageDescription APIs are gated behind a "tools version" that
every manifest must declare. This means, packages don't automatically
get access to the new APIs. They need to update their declared tools
version in order to use the new API. This is basically similar to the
minimum deployment target version we have for our OSes.
This gating is important for allowing packages to maintain backwards
compatibility. SwiftPM currently checks for API usages at runtime in
order to implement this gating. This works reasonably well but can lead
to a poor experience with features like code-completion and module
interface generation in IDEs and editors (that use sourcekit-lsp) as
SwiftPM has no control over these features.
`#assert` is a new static assertion statement that will let us write
tests for the new constant evaluation infrastructure that we are working
on. `#assert` works by lowering to a `Builtin.poundAssert` SIL
instruction. The constant evaluation infrastructure will look for these
SIL instructions, const-evaluate their conditions, and emit errors if
the conditions are non-constant or false.
This commit implements parsing, typechecking and SILGen for `#assert`.
Dynamic replacements are currently written in extensions as
extension ExtendedType {
@_dynamicReplacement(for: replacedFun())
func replacement() { }
}
The runtime implementation allows an implementation in the future where
dynamic replacements are gather in a scope and can be dynamically
enabled and disabled.
For example:
dynamic_extension_scope CollectionOfReplacements {
extension ExtentedType {
func replacedFun() {}
}
extension ExtentedType2 {
func replacedFun() {}
}
}
CollectionOfReplacements.enable()
CollectionOfReplacements.disable()
The `Stmt` and `Expr` classes had both `dump` and `print` methods that behaved similarly, making it unclear what each method was for. Following a conversation in https://forums.swift.org/t/unifying-printing-logic-in-astdumper/15995/6 the `dump` methods will be used to print the S-Expression-like ASTs, and the `print` methods will be used to print the more textual ASTPrinter-based representations. The `Stmt` and `Expr` classes seem to be where this distinction was more ambiguous. These changes should fix that ambiguity.
A few other classes also have `print` methods used to print straightforward representations that are neither the S-Expressions nor ASTPrinters. These were left as they are, as they don't cause the same ambiguity.
It should be noted that the ASTPrinter implementations themselves haven't yet been finished and aren't a part of these changes.
Add parsing, type checking, serialization, and deserialization support
for specifying multiple types as "designated" for operator lookup for
a given operator declaration.
The constraint solver still considers only the first type when
deciding the order to attempt the elements of a disjunction, so this
doesn't really change behavior yet.
`\.self` is the final chosen syntax. Implement support for this syntax, and remove the stopgap builtin and `WritableKeyPath._identity` property that were in place before.
The support is gated by a frontend option,
-enable-operator-designated-protocols.
This means that in an operator declaration we can declare a protocol
which has one or more requirements specifying this operator. The
operators from that designated protocol will be the first ones we try
when type checking an expression. If we successfully typecheck using
the operators specified in that protocol, we do not attempt any other
overloads of the same operator.
This makes it possible to dramatically speed up successful
typechecking.
Most of this patch is just removing special cases for materializeForSet
or other fairly mechanical replacements. Unfortunately, the rest is
still a fairly big change, and not one that can be easily split apart
because of the quite reasonable reliance on metaprogramming throughout
the compiler. And, of course, there are a bunch of test updates that
have to be sync'ed with the actual change to code-generation.
This is SR-7134.
I needed this for materializeForSet remission, but it makes inherited
variadic initializers work, too.
I tried to make this a reasonable starting point for a real language
feature. Here's what's still missing:
- syntax
- semantic restrictions to ensure that the expression isn't written in
invalid places or arbitrarily converted
- SILGen support for expansions that aren't the only variadic argument
rdar://16331406
Introduce ExtensionDecl::getExtendedNominal() to provide the nominal
type declaration that the extension declaration extends. Move most
of the existing callers of the callers to getExtendedType() over to
getExtendedNominal(), because they don’t need the full type information.
ExtensionDecl::getExtendedNominal() is itself not very interesting yet,
because it depends on getExtendedType().
For now, the accessors have been underscored as `_read` and `_modify`.
I'll prepare an evolution proposal for this feature which should allow
us to remove the underscores or, y'know, rename them to `purple` and
`lettuce`.
`_read` accessors do not make any effort yet to avoid copying the
value being yielded. I'll work on it in follow-up patches.
Opaque accesses to properties and subscripts defined with `_modify`
accessors will use an inefficient `materializeForSet` pattern that
materializes the value to a temporary instead of accessing it in-place.
That will be fixed by migrating to `modify` over `materializeForSet`,
which is next up after the `read` optimizations.
SIL ownership verification doesn't pass yet for the test cases here
because of a general fault in SILGen where borrows can outlive their
borrowed value due to being cleaned up on the general cleanup stack
when the borrowed value is cleaned up on the formal-access stack.
Michael, Andy, and I discussed various ways to fix this, but it seems
clear to me that it's not in any way specific to coroutine accesses.
rdar://35399664
- Print "assign_expr" with color (using `printCommon`).
- Print "function_ref" for UnresolvedDotExpr with color, to be
consistent with all other "function_ref" printing.
Most instances of "decl=" were printed with color but some were not.
Now, all instances of "decl=" (and the subsequent ValueDecl or
ConcreteDeclRef) are printed with color.
Some colored open parentheses (printed by `printCommon`) had uncolored
closing parenthesis counterparts. Now, all such closing parentheses are
colored.
The storage kind has been replaced with three separate "impl kinds",
one for each of the basic access kinds (read, write, and read/write).
This makes it far easier to mix-and-match implementations of different
accessors, as well as subtleties like implementing both a setter
and an independent read/write operation.
AccessStrategy has become a bit more explicit about how exactly the
access should be implemented. For example, the accessor-based kinds
now carry the exact accessor intended to be used. Also, I've shifted
responsibilities slightly between AccessStrategy and AccessSemantics
so that AccessSemantics::Ordinary can be used except in the sorts of
semantic-bypasses that accessor synthesis wants. This requires
knowing the correct DC of the access when computing the access strategy;
the upshot is that SILGenFunction now needs a DC.
Accessor synthesis has been reworked so that only the declarations are
built immediately; body synthesis can be safely delayed out of the main
decl-checking path. This caused a large number of ramifications,
especially for lazy properties, and greatly inflated the size of this
patch. That is... really regrettable. The impetus for changing this
was necessity: I needed to rework accessor synthesis to end its reliance
on distinctions like Stored vs. StoredWithTrivialAccessors, and those
fixes were exposing serious re-entrancy problems, and fixing that... well.
Breaking the fixes apart at this point would be a serious endeavor.
