Revert "Introduce adoption mode for Swift features"

Author: rintaro

.github/CODEOWNERS

@@ -269,7 +269,7 @@
 /unittests/AST/                           @hborla @slavapestov @xedin
 /unittests/AST/*Evaluator*                @CodaFi @slavapestov
 /unittests/DependencyScan/                @artemcm @cachemeifyoucan
-/unittests/Frontend*/                     @artemcm @tshortli
+/unittests/FrontendTool/                  @artemcm @tshortli
 /unittests/Parse/                         @ahoppen @bnbarham @CodaFi @DougGregor @hamishknight @rintaro
 /unittests/Reflection/                    @slavapestov
 /unittests/SIL/                           @jckarter

include/swift/AST/DiagnosticsFrontend.def

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -50,20 +50,6 @@ GROUPED_WARNING(feature_not_experimental, StrictLanguageFeatures, DefaultIgnore,
                 "use -%select{disable|enable}1-upcoming-feature instead",
                 (StringRef, bool))
 
-GROUPED_WARNING(invalid_feature_mode, StrictLanguageFeatures, none,
-                "'%0' is not a recognized mode for feature '%1'"
-                "%select{|; did you mean '%2'?}3",
-                (StringRef, StringRef, StringRef, bool))
-
-GROUPED_WARNING(cannot_disable_feature_with_mode, StrictLanguageFeatures, none,
-                "'%0' argument '%1' cannot specify a mode",
-                (StringRef, StringRef))
-
-GROUPED_WARNING(feature_does_not_support_adoption_mode, StrictLanguageFeatures,
-                none,
-                "feature '%0' does not support adoption mode",
-                (StringRef))
-
 ERROR(error_unknown_library_level, none,
       "unknown library level '%0', "
       "expected one of 'api', 'spi', 'ipi', or 'other'", (StringRef))

include/swift/Basic/BasicBridging.h

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2022 - 2025 Apple Inc. and the Swift project authors
+// Copyright (c) 2022 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -214,8 +214,7 @@ void BridgedData_free(BridgedData data);
 //===----------------------------------------------------------------------===//
 
 enum ENUM_EXTENSIBILITY_ATTR(open) BridgedFeature {
-#define LANGUAGE_FEATURE(FeatureName, IsAdoptable, SENumber, Description)      \
-  FeatureName,
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description) FeatureName,
 #include "swift/Basic/Features.def"
 };
 

include/swift/Basic/Feature.h

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -21,16 +21,14 @@ namespace swift {
 class LangOptions;
 
 /// Enumeration describing all of the named features.
-enum class Feature : uint16_t {
-#define LANGUAGE_FEATURE(FeatureName, IsAdoptable, SENumber, Description)      \
-  FeatureName,
+enum class Feature {
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description) FeatureName,
 #include "swift/Basic/Features.def"
 };
 
 constexpr unsigned numFeatures() {
   enum Features {
-#define LANGUAGE_FEATURE(FeatureName, IsAdoptable, SENumber, Description)      \
-  FeatureName,
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description) FeatureName,
 #include "swift/Basic/Features.def"
     NumFeatures
   };
@@ -63,9 +61,6 @@ std::optional<Feature> getExperimentalFeature(llvm::StringRef name);
 /// \c None if it does not have such a version.
 std::optional<unsigned> getFeatureLanguageVersion(Feature feature);
 
-/// Determine whether the given feature supports adoption mode.
-bool isFeatureAdoptable(Feature feature);
-
 /// Determine whether this feature should be included in the
 /// module interface
 bool includeInModuleInterface(Feature feature);

include/swift/Basic/Features.def

@@ -14,28 +14,14 @@
 // features.
 //
 //
-// LANGUAGE_FEATURE(FeatureName, IsAdoptable, SENumber, Description)
+// LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 //
 //   The LANGUAGE_FEATURE macro describes each named feature that is
 //   introduced in Swift. It allows Swift code to check for a particular
 //   feature with "#if $FeatureName" in source code.
 //
 //     FeatureName: The name given to this feature to be used in source code,
 //       e.g., AsyncAwait.
-//     IsAdoptable: Whether the feature implements adoption mode.
-//
-//       If the feature is upcoming (source-breaking) and provides for a
-//       mechanical code migration, it should implement adoption mode.
-//
-//       Adoption mode is a feature-oriented code migration mechanism: a mode
-//       of operation that should produce compiler warnings with attached
-//       fix-its that can be applied to preserve the behavior of the code once
-//       the upcoming feature is enacted.
-//       These warnings must belong to a diagnostic group named after the
-//       feature. Adoption mode itself *and* the fix-its it produces must be
-//       source and binary compatible with how the code is compiled when the
-//       feature is disabled.
-//
 //     SENumber: The number assigned to this feature in the Swift Evolution
 //       process, or 0 if there isn't one.
 //     Description: A string literal describing the feature.
@@ -105,14 +91,13 @@
 #endif
 
 #ifndef SUPPRESSIBLE_LANGUAGE_FEATURE
-  #define SUPPRESSIBLE_LANGUAGE_FEATURE(FeatureName, SENumber, Description)    \
-    LANGUAGE_FEATURE(FeatureName, /*IsAdoptable=*/false, SENumber,             \
-                     Description)
+#  define SUPPRESSIBLE_LANGUAGE_FEATURE(FeatureName, SENumber, Description) \
+  LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 #endif
 
 #ifndef OPTIONAL_LANGUAGE_FEATURE
-  #define OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Description)        \
-    LANGUAGE_FEATURE(FeatureName, /*IsAdoptable=*/false, SENumber, Description)
+#  define OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Description) \
+  LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 #endif
 
 // A feature that's both conditionally-suppressible and experimental.
@@ -131,35 +116,20 @@
 #endif
 
 #ifndef CONDITIONALLY_SUPPRESSIBLE_LANGUAGE_FEATURE
-  #define CONDITIONALLY_SUPPRESSIBLE_LANGUAGE_FEATURE(FeatureName, SENumber,   \
-                                                      Description)             \
-    LANGUAGE_FEATURE(FeatureName, /*IsAdoptable=*/false, SENumber,             \
-                     Description)
-#endif
-
-// An upcoming feature that supports adoption mode.
-#ifndef ADOPTABLE_UPCOMING_FEATURE
-  #if defined(UPCOMING_FEATURE)
-    #define ADOPTABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)         \
-      UPCOMING_FEATURE(FeatureName, SENumber, Version)
-  #else
-    #define ADOPTABLE_UPCOMING_FEATURE(FeatureName, SENumber, Version)         \
-      LANGUAGE_FEATURE(FeatureName, /*IsAdoptable=*/true, SENumber,            \
-                       #FeatureName)
-  #endif
+#  define CONDITIONALLY_SUPPRESSIBLE_LANGUAGE_FEATURE(FeatureName, SENumber, Description) \
+     LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 #endif
 
 #ifndef UPCOMING_FEATURE
-  #define UPCOMING_FEATURE(FeatureName, SENumber, Version)                     \
-    LANGUAGE_FEATURE(FeatureName, /*IsAdoptable=*/false, SENumber,             \
-                     #FeatureName)
+#  define UPCOMING_FEATURE(FeatureName, SENumber, Version)   \
+     LANGUAGE_FEATURE(FeatureName, SENumber, #FeatureName)
 #endif
 
 #ifndef EXPERIMENTAL_FEATURE
-  // Warning: setting `AvailableInProd` to `true` on a feature means that the
-  // flag cannot be dropped in the future.
-  #define EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)                   \
-    LANGUAGE_FEATURE(FeatureName, /*IsAdoptable=*/false, 0, #FeatureName)
+// Warning: setting `AvailableInProd` to `true` on a feature means that the flag
+//          cannot be dropped in the future.
+#  define EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)  \
+     LANGUAGE_FEATURE(FeatureName, 0, #FeatureName)
 #endif
 
 #ifndef EXPERIMENTAL_FEATURE_EXCLUDED_FROM_MODULE_INTERFACE
@@ -168,9 +138,8 @@
 #endif
 
 #ifndef BASELINE_LANGUAGE_FEATURE
-  #define BASELINE_LANGUAGE_FEATURE(FeatureName, SENumber, Description)        \
-    LANGUAGE_FEATURE(FeatureName, /*IsAdoptable=*/false, SENumber,             \
-                     Description)
+#  define BASELINE_LANGUAGE_FEATURE(FeatureName, SENumber, Description) \
+  LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 #endif
 
 BASELINE_LANGUAGE_FEATURE(AsyncAwait, 296, "async/await")
@@ -241,14 +210,10 @@ BASELINE_LANGUAGE_FEATURE(BodyMacros, 415, "Function body macros")
 SUPPRESSIBLE_LANGUAGE_FEATURE(SendingArgsAndResults, 430, "Sending arg and results")
 BASELINE_LANGUAGE_FEATURE(BorrowingSwitch, 432, "Noncopyable type pattern matching")
 CONDITIONALLY_SUPPRESSIBLE_LANGUAGE_FEATURE(IsolatedAny, 431, "@isolated(any) function types")
-LANGUAGE_FEATURE(IsolatedAny2, /*IsAdoptable=*/false, 431,
-                 "@isolated(any) function types")
-LANGUAGE_FEATURE(ObjCImplementation, /*IsAdoptable=*/false, 436,
-                 "@objc @implementation extensions")
-LANGUAGE_FEATURE(NonescapableTypes, /*IsAdoptable=*/false, 446,
-                 "Nonescapable types")
-LANGUAGE_FEATURE(BuiltinEmplaceTypedThrows, /*IsAdoptable=*/false, 0,
-                 "Builtin.emplace typed throws")
+LANGUAGE_FEATURE(IsolatedAny2, 431, "@isolated(any) function types")
+LANGUAGE_FEATURE(ObjCImplementation, 436, "@objc @implementation extensions")
+LANGUAGE_FEATURE(NonescapableTypes, 446, "Nonescapable types")
+LANGUAGE_FEATURE(BuiltinEmplaceTypedThrows, 0, "Builtin.emplace typed throws")
 SUPPRESSIBLE_LANGUAGE_FEATURE(MemorySafetyAttributes, 458, "@unsafe attribute")
 
 // Swift 6
@@ -269,7 +234,7 @@ UPCOMING_FEATURE(NonfrozenEnumExhaustivity, 192, 6)
 UPCOMING_FEATURE(GlobalActorIsolatedTypesUsability, 0434, 6)
 
 // Swift 7
-ADOPTABLE_UPCOMING_FEATURE(ExistentialAny, 335, 7)
+UPCOMING_FEATURE(ExistentialAny, 335, 7)
 UPCOMING_FEATURE(InternalImportsByDefault, 409, 7)
 UPCOMING_FEATURE(MemberImportVisibility, 444, 7)
 
@@ -520,7 +485,6 @@ EXPERIMENTAL_FEATURE(CompileTimeValues, true)
 #undef EXPERIMENTAL_FEATURE_EXCLUDED_FROM_MODULE_INTERFACE
 #undef EXPERIMENTAL_FEATURE
 #undef UPCOMING_FEATURE
-#undef ADOPTABLE_UPCOMING_FEATURE
 #undef BASELINE_LANGUAGE_FEATURE
 #undef OPTIONAL_LANGUAGE_FEATURE
 #undef CONDITIONALLY_SUPPRESSIBLE_EXPERIMENTAL_FEATURE

include/swift/Basic/LangOptions.h

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -20,6 +20,7 @@
 
 #include "swift/Basic/CXXStdlibKind.h"
 #include "swift/Basic/Feature.h"
+#include "swift/Basic/FixedBitSet.h"
 #include "swift/Basic/FunctionBodySkipping.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/PlaygroundOption.h"
@@ -724,6 +725,19 @@ namespace swift {
       return cxxInteropCompatVersion.isVersionAtLeast(major, minor);
     }
 
+    /// Determine whether the given feature is enabled.
+    bool hasFeature(Feature feature) const;
+
+    /// Determine whether the given feature is enabled, looking up the feature
+    /// by name.
+    bool hasFeature(llvm::StringRef featureName) const;
+
+    /// Enable the given feature.
+    void enableFeature(Feature feature) { Features.insert(feature); }
+
+    /// Disable the given feature.
+    void disableFeature(Feature feature) { Features.remove(feature); }
+
     /// Sets the "_hasAtomicBitWidth" conditional.
     void setHasAtomicBitWidth(llvm::Triple triple);
 
@@ -808,68 +822,10 @@ namespace swift {
         PlatformConditionValues;
     llvm::SmallVector<std::string, 2> CustomConditionalCompilationFlags;
 
-  public:
-    // MARK: Features
-    // =========================================================================
-
-    /// A wrapper around the feature state enumeration.
-    struct FeatureState {
-      enum Kind : uint8_t { Off, EnabledForAdoption, Enabled };
-
-    private:
-      Feature feature;
-      Kind state;
-
-    public:
-      FeatureState(Feature feature, Kind state)
-          : feature(feature), state(state) {}
-
-      /// Returns whether the feature is enabled.
-      bool isEnabled() const;
-
-      /// Returns whether the feature is enabled in adoption mode. Should only
-      /// be called if the feature is known to support this mode.
-      bool isEnabledForAdoption() const;
-
-      operator Kind() const { return state; }
-    };
-
-  private:
-    class FeatureStateStorage {
-      std::vector<FeatureState::Kind> states;
-
-    public:
-      FeatureStateStorage();
-
-      /// Sets the given state for the given feature.
-      void setState(Feature feature, FeatureState::Kind state);
-
-      /// Retrieves the state of the given feature.
-      FeatureState getState(Feature feature) const;
-    };
-
-    /// The states of language features.
-    FeatureStateStorage featureStates;
-
-  public:
-    /// Retrieve the state of the given feature.
-    FeatureState getFeatureState(Feature feature) const;
-
-    /// Returns whether the given feature is enabled.
-    bool hasFeature(Feature feature) const;
-
-    /// Returns whether a feature with the given name is enabled. Returns
-    /// `false` if a feature by this name is not known.
-    bool hasFeature(llvm::StringRef featureName) const;
-
-    /// Enables the given feature (enables in adoption mode if `forAdoption` is
-    /// `true`).
-    void enableFeature(Feature feature, bool forAdoption = false);
-
-    /// Disables the given feature.
-    void disableFeature(Feature feature);
-
-    // =========================================================================
+    /// The set of features that have been enabled. Doesn't include upcoming
+    /// features, which are checked against the language version in
+    /// `hasFeature`.
+    FixedBitSet<numFeatures(), Feature> Features;
   };
 
   class TypeCheckerOptions final {

lib/AST/ASTPrinter.cpp

@@ -1,7 +1,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -3267,7 +3267,7 @@ suppressingFeatureExecutionAttribute(PrintOptions &options,
 static void suppressingFeature(PrintOptions &options, Feature feature,
                                llvm::function_ref<void()> action) {
   switch (feature) {
-#define LANGUAGE_FEATURE(FeatureName, IsAdoptable, SENumber, Description)      \
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
   case Feature::FeatureName:                                                   \
     llvm_unreachable("not a suppressible feature");
 #define SUPPRESSIBLE_LANGUAGE_FEATURE(FeatureName, SENumber, Description)      \

lib/AST/FeatureSet.cpp

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2024 - 2025 Apple Inc. and the Swift project authors
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -45,7 +45,7 @@ static bool usesTypeMatching(Decl *decl, llvm::function_ref<bool(Type)> fn) {
 
 #define BASELINE_LANGUAGE_FEATURE(FeatureName, SENumber, Description)          \
   static bool usesFeature##FeatureName(Decl *decl) { return false; }
-#define LANGUAGE_FEATURE(FeatureName, IsAdoptable, SENumber, Description)
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 #include "swift/Basic/Features.def"
 
 #define UNINTERESTING_FEATURE(FeatureName)                                     \
@@ -551,7 +551,7 @@ void FeatureSet::collectFeaturesUsed(Decl *decl, InsertOrRemove operation) {
 
   // Go through each of the features, checking whether the
   // declaration uses that feature.
-#define LANGUAGE_FEATURE(FeatureName, IsAdoptable, SENumber, Description)      \
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
   if (CHECK(usesFeature##FeatureName))                                         \
     collectRequiredFeature(Feature::FeatureName, operation);
 #define SUPPRESSIBLE_LANGUAGE_FEATURE(FeatureName, SENumber, Description)      \