Merge pull request #4712 from swiftwasm/main

[pull] swiftwasm from main

Author: kateinoigakukun

CHANGELOG.md

@@ -3,6 +3,17 @@ CHANGELOG
 
 _**Note:** This is in reverse chronological order, so newer entries are added to the top._
 
+## Swift 5.8
+
+* [SE-0362][]:
+
+  The compiler flag `-enable-upcoming-feature X` can now be used to enable a specific feature `X` that has been accepted by the evolution process, but whose introduction into the language is waiting for the next major version (e.g., version 6). The `X` is specified by any proposal that falls into this category:
+  * `ConciseMagicFile` enables the new `#file` semantics in [SE-0274][].
+  * `ForwardTrailingClosures` disables the "backward" scanning behavior of [SE-0286][].
+  * `BareSlashRegexLiterals` enables the regex literal syntax of [SE-0352][].
+
+  Features can be detected in source code with `#if hasFeature(X)`.
+
 ## Swift 5.7
 
 * The Swift compiler no longer warns about redundant requirements in generic declarations. For example,
@@ -9459,6 +9470,7 @@ Swift 1.0
 [SE-0267]: <https://github.com/apple/swift-evolution/blob/main/proposals/0267-where-on-contextually-generic.md>
 [SE-0268]: <https://github.com/apple/swift-evolution/blob/main/proposals/0268-didset-semantics.md>
 [SE-0269]: <https://github.com/apple/swift-evolution/blob/main/proposals/0269-implicit-self-explicit-capture.md>
+[SE-0274]: <https://github.com/apple/swift-evolution/blob/main/proposals/0274-magic-file.md>
 [SE-0276]: <https://github.com/apple/swift-evolution/blob/main/proposals/0276-multi-pattern-catch-clauses.md>
 [SE-0279]: <https://github.com/apple/swift-evolution/blob/main/proposals/0279-multiple-trailing-closures.md>
 [SE-0280]: <https://github.com/apple/swift-evolution/blob/main/proposals/0280-enum-cases-as-protocol-witnesses.md>
@@ -9509,6 +9521,7 @@ Swift 1.0
 [SE-0355]: <https://github.com/apple/swift-evolution/blob/main/proposals/0355-regex-syntax-run-time-construction.md>
 [SE-0357]: <https://github.com/apple/swift-evolution/blob/main/proposals/0357-regex-string-processing-algorithms.md>
 [SE-0358]: <https://github.com/apple/swift-evolution/blob/main/proposals/0358-primary-associated-types-in-stdlib.md>
+[SE-0362]: <https://github.com/apple/swift-evolution/blob/main/proposals/0362-piecemeal-future-features.md>
 
 [SR-75]: <https://bugs.swift.org/browse/SR-75>
 [SR-106]: <https://bugs.swift.org/browse/SR-106>

include/swift/AST/Decl.h

@@ -35,7 +35,6 @@
 #include "swift/AST/TypeAlignments.h"
 #include "swift/AST/TypeWalker.h"
 #include "swift/AST/Types.h"
-#include "swift/AST/Witness.h"
 #include "swift/Basic/ArrayRefView.h"
 #include "swift/Basic/Compiler.h"
 #include "swift/Basic/Debug.h"
@@ -105,6 +104,7 @@ namespace swift {
   class ValueDecl;
   class VarDecl;
   class OpaqueReturnTypeRepr;
+  class Witness;
 
   namespace ast_scope {
   class AbstractPatternEntryScope;

include/swift/AST/DiagnosticsFrontend.def

@@ -40,6 +40,10 @@ ERROR(error_experimental_feature_not_available, none,
       "experimental feature '%0' cannot be enabled in a production compiler",
       (StringRef))
 
+ERROR(error_upcoming_feature_on_by_default, none,
+      "upcoming feature '%0' is already enabled as of Swift version %1",
+      (StringRef, unsigned))
+
 ERROR(error_unknown_library_level, none,
       "unknown library level '%0', "
       "expected one of 'api', 'spi' or 'other'", (StringRef))

include/swift/AST/DiagnosticsParse.def

@@ -422,6 +422,8 @@ ERROR(expected_lparen_initializer,PointsToFirstBadToken,
       "expected '(' for initializer parameters", ())
 ERROR(initializer_has_name,PointsToFirstBadToken,
       "initializers cannot have a name", ())
+ERROR(initializer_result_type,PointsToFirstBadToken,
+      "initializers cannot have a result type", ())
 
 // Destructor
 ERROR(destructor_decl_outside_class,none,

include/swift/AST/RequirementEnvironment.h

@@ -35,7 +35,7 @@ namespace swift {
 /// environment are the type parameters of the conformance context
 /// (\c conformanceDC) with another (deeper) level of type parameters for
 /// generic requirements. See the \c Witness class for more information about
-/// this synthetic environment.
+/// the witness thunk signature.
 class RequirementEnvironment {
   /// A generic signature that combines the generic parameters of the
   /// concrete conforming type with the generic parameters of the
@@ -52,7 +52,7 @@ class RequirementEnvironment {
   /// <Self : P, T>
   /// <A, B, T>
   ///
-  /// The synthetic signature in this case is just the witness signature.
+  /// The witness thunk signature in this case is just the witness signature.
   ///
   /// It may be that the witness is more generic than the requirement,
   /// for example:
@@ -65,22 +65,21 @@ class RequirementEnvironment {
   /// <Self : P>
   /// <A, B, T>
   ///
-  /// The synthetic signature is just:
+  /// The witness thunk signature is just:
   ///
   /// <A, B>
   ///
-  /// The witness thunk emitted by SILGen uses the synthetic signature.
+  /// The witness thunk emitted by SILGen uses the witness thunk signature.
   /// Therefore one invariant we preserve is that the witness thunk is
   /// ABI compatible with the requirement's function type.
-  GenericSignature syntheticSignature = GenericSignature();
-  GenericEnvironment *syntheticEnvironment = nullptr;
+  GenericSignature witnessThunkSig = GenericSignature();
 
   /// The generic signature of the protocol requirement member.
   GenericSignature reqSig = GenericSignature();
 
   /// A substitution map mapping the requirement signature to the
-  /// generic parameters of the synthetic signature.
-  SubstitutionMap reqToSyntheticEnvMap;
+  /// generic parameters of the witness thunk signature.
+  SubstitutionMap reqToWitnessThunkSigMap;
 
 public:
   /// Create a new environment for matching the given requirement within a
@@ -102,20 +101,20 @@ class RequirementEnvironment {
                          ClassDecl *covariantSelf,
                          ProtocolConformance *conformance);
 
-  /// Retrieve the synthetic generic environment.
-  GenericEnvironment *getSyntheticEnvironment() const {
-    return syntheticEnvironment;
-  }
-
   /// Retrieve the generic signature of the requirement.
   GenericSignature getRequirementSignature() const {
     return reqSig;
   }
 
+  /// Retrieve the generic signature of the witness thunk.
+  GenericSignature getWitnessThunkSignature() const {
+    return witnessThunkSig;
+  }
+
   /// Retrieve the substitution map that maps the interface types of the
-  /// requirement to the interface types of the synthetic environment.
-  SubstitutionMap getRequirementToSyntheticMap() const {
-    return reqToSyntheticEnvMap;
+  /// requirement to the interface types of the witness thunk signature.
+  SubstitutionMap getRequirementToWitnessThunkSubs() const {
+    return reqToWitnessThunkSigMap;
   }
 };
 

include/swift/AST/Witness.h

@@ -72,7 +72,7 @@ class ValueDecl;
 /// The witness for \c R.foo(x:) is \c X<U, V>.foo(x:), but the generic
 /// functions that describe the generic requirement in \c R and the generic
 /// method in \c X have very different signatures. To handle this case, the
-/// \c Witness class produces a "synthetic" environment that pulls together
+/// \c Witness class produces a witness thunk signature that pulls together
 /// all of the information needed to map from the requirement to the witness.
 /// It is a generic environment that combines the constraints of the
 /// requirement with the constraints from the context of the protocol
@@ -81,19 +81,19 @@ class ValueDecl;
 /// environment are those of the context of the protocol conformance (\c U
 /// and \c V, in the example above) and the innermost generic parameters are
 /// those of the generic requirement (\c T, in the example above). The
-/// \c Witness class contains this synthetic environment (both its generic
+/// \c Witness class contains this witness thunk signature (both its generic
 /// signature and a generic environment providing archetypes), a substitution
 /// map that allows one to map the interface types of the requirement into
-/// the interface types of the synthetic domain, and the set of substitutions
-/// required to use the witness from the synthetic domain (e.g., how one would
+/// the interface types of the witness thunk domain, and the set of substitutions
+/// required to use the witness from the witness thunk domain (e.g., how one would
 /// call the witness from the witness thunk).
 class Witness {
   struct StoredWitness {
     /// The witness declaration, along with the substitutions needed to use
-    /// the witness declaration from the synthetic environment.
+    /// the witness declaration from the witness thunk signature.
     ConcreteDeclRef declRef;
-    GenericEnvironment *syntheticEnvironment;
-    SubstitutionMap reqToSyntheticEnvSubs;
+    GenericSignature witnessThunkSig;
+    SubstitutionMap reqToWitnessThunkSigSubs;
     /// The derivative generic signature, when the requirement is a derivative
     /// function.
     GenericSignature derivativeGenSig;
@@ -124,7 +124,7 @@ class Witness {
 
   /// Create a witness for the given requirement.
   ///
-  /// Deserialized witnesses do not have a synthetic environment.
+  /// Deserialized witnesses do not have a witness thunk signature.
   static Witness forDeserialized(ValueDecl *decl,
                                  SubstitutionMap substitutions,
                                  Optional<ActorIsolation> enterIsolation) {
@@ -139,12 +139,12 @@ class Witness {
   /// \param decl The declaration for the witness.
   ///
   /// \param substitutions The substitutions required to use the witness from
-  /// the synthetic environment.
+  /// the witness thunk signature.
   ///
-  /// \param syntheticEnv The synthetic environment.
+  /// \param witnessThunkSig The witness thunk signature.
   ///
-  /// \param reqToSyntheticEnvSubs The mapping from the interface types of the
-  /// requirement into the interface types of the synthetic environment.
+  /// \param reqToWitnessThunkSigSubs The mapping from the interface types of the
+  /// requirement into the interface types of the witness thunk signature.
   ///
   /// \param derivativeGenSig The derivative generic signature, when the
   /// requirement is a derivative function.
@@ -153,13 +153,13 @@ class Witness {
   /// need to hop to before calling the witness.
   Witness(ValueDecl *decl,
           SubstitutionMap substitutions,
-          GenericEnvironment *syntheticEnv,
-          SubstitutionMap reqToSyntheticEnvSubs,
+          GenericSignature witnessThunkSig,
+          SubstitutionMap reqToWitnessThunkSigSubs,
           GenericSignature derivativeGenSig,
           Optional<ActorIsolation> enterIsolation);
 
   /// Retrieve the witness declaration reference, which includes the
-  /// substitutions needed to use the witness from the synthetic environment
+  /// substitutions needed to use the witness from the witness thunk signature
   /// (if any).
   ConcreteDeclRef getDeclRef() const {
     if (auto stored = storage.dyn_cast<StoredWitness *>())
@@ -175,26 +175,23 @@ class Witness {
   explicit operator bool() const { return !storage.isNull(); }
 
   /// Retrieve the substitutions required to use this witness from the
-  /// synthetic environment.
-  ///
-  /// The substitutions are substitutions for the witness, providing interface
-  /// types from the synthetic environment.
+  /// witness thunk signature.
   SubstitutionMap getSubstitutions() const {
     return getDeclRef().getSubstitutions();
   }
 
-  /// Retrieve the synthetic generic environment.
-  GenericEnvironment *getSyntheticEnvironment() const {
+  /// Retrieve the witness thunk generic signature.
+  GenericSignature getWitnessThunkSignature() const {
     if (auto *storedWitness = storage.dyn_cast<StoredWitness *>())
-      return storedWitness->syntheticEnvironment;
+      return storedWitness->witnessThunkSig;
     return nullptr;
   }
 
   /// Retrieve the substitution map that maps the interface types of the
-  /// requirement to the interface types of the synthetic environment.
-  SubstitutionMap getRequirementToSyntheticSubs() const {
+  /// requirement to the interface types of the witness thunk signature.
+  SubstitutionMap getRequirementToWitnessThunkSubs() const {
     if (auto *storedWitness = storage.dyn_cast<StoredWitness *>())
-      return storedWitness->reqToSyntheticEnvSubs;
+      return storedWitness->reqToWitnessThunkSigSubs;
     return {};
   }
 

include/swift/Basic/Feature.h

@@ -53,7 +53,7 @@ inline bool featureImpliesFeature(Feature feature, Feature implied) {
 }
 
 /// Get the feature corresponding to this "future" feature, if there is one.
-llvm::Optional<Feature> getFutureFeature(llvm::StringRef name);
+llvm::Optional<Feature> getUpcomingFeature(llvm::StringRef name);
 
 /// Get the feature corresponding to this "experimental" feature, if there is
 /// one.

include/swift/Basic/Features.def

@@ -48,8 +48,8 @@
   LANGUAGE_FEATURE(FeatureName, SENumber, Description, Option)
 #endif
 
-#ifndef FUTURE_FEATURE
-#  define FUTURE_FEATURE(FeatureName, SENumber, Version)   \
+#ifndef UPCOMING_FEATURE
+#  define UPCOMING_FEATURE(FeatureName, SENumber, Version)   \
      LANGUAGE_FEATURE(FeatureName, SENumber, #FeatureName, \
                       langOpts.hasFeature(#FeatureName))
 #endif
@@ -90,9 +90,9 @@ SUPPRESSIBLE_LANGUAGE_FEATURE(PrimaryAssociatedTypes2, 346, "Primary associated
 SUPPRESSIBLE_LANGUAGE_FEATURE(UnavailableFromAsync, 0, "@_unavailableFromAsync", true)
 SUPPRESSIBLE_LANGUAGE_FEATURE(NoAsyncAvailability, 340, "@available(*, noasync)", true)
 
-FUTURE_FEATURE(ConciseMagicFile, 274, 6)
-FUTURE_FEATURE(ForwardTrailingClosures, 286, 6)
-FUTURE_FEATURE(BareSlashRegexLiterals, 354, 6)
+UPCOMING_FEATURE(ConciseMagicFile, 274, 6)
+UPCOMING_FEATURE(ForwardTrailingClosures, 286, 6)
+UPCOMING_FEATURE(BareSlashRegexLiterals, 354, 6)
 
 EXPERIMENTAL_FEATURE(StaticAssert)
 EXPERIMENTAL_FEATURE(VariadicGenerics)
@@ -118,6 +118,6 @@ EXPERIMENTAL_FEATURE(AdditiveArithmeticDerivedConformances)
 EXPERIMENTAL_FEATURE(SendableCompletionHandlers)
 
 #undef EXPERIMENTAL_FEATURE
-#undef FUTURE_FEATURE
+#undef UPCOMING_FEATURE
 #undef SUPPRESSIBLE_LANGUAGE_FEATURE
 #undef LANGUAGE_FEATURE

include/swift/Basic/LangOptions.h

@@ -28,6 +28,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Support/Regex.h"

include/swift/Option/Options.td

@@ -696,6 +696,11 @@ def enable_experimental_feature :
   Flags<[FrontendOption]>,
   HelpText<"Enable an experimental feature">;
 
+def enable_upcoming_feature : Separate<["-"], "enable-upcoming-feature">,
+  Flags<[FrontendOption]>,
+  HelpText<"Enable a feature that will be introduced in an upcoming language "
+           "version">;
+
 def Rpass_EQ : Joined<["-"], "Rpass=">,
   Flags<[FrontendOption]>,
   HelpText<"Report performed transformations by optimization passes whose "