AST: Promote RethrowsProtocol feature to baseline.

Author: tshortli

include/swift/Basic/Features.def

@@ -136,7 +136,7 @@ BASELINE_LANGUAGE_FEATURE(EffectfulProp, 310, "Effectful properties")
 BASELINE_LANGUAGE_FEATURE(MarkerProtocol, 0, "@_marker protocol")
 BASELINE_LANGUAGE_FEATURE(Actors, 0, "actors")
 BASELINE_LANGUAGE_FEATURE(ConcurrentFunctions, 0, "@concurrent functions")
-LANGUAGE_FEATURE(RethrowsProtocol, 0, "@rethrows protocol")
+BASELINE_LANGUAGE_FEATURE(RethrowsProtocol, 0, "@rethrows protocol")
 BASELINE_LANGUAGE_FEATURE(GlobalActors, 316, "Global actors")
 BASELINE_LANGUAGE_FEATURE(BuiltinJob, 0, "Builtin.Job type")
 BASELINE_LANGUAGE_FEATURE(Sendable, 0, "Sendable and @Sendable")

lib/AST/FeatureSet.cpp

@@ -49,81 +49,6 @@ static bool usesTypeMatching(Decl *decl, llvm::function_ref<bool(Type)> fn) {
 #define UNINTERESTING_FEATURE(FeatureName)                                     \
   static bool usesFeature##FeatureName(Decl *decl) { return false; }
 
-static bool usesFeatureRethrowsProtocol(Decl *decl,
-                                        SmallPtrSet<Decl *, 16> &checked) {
-  // Make sure we don't recurse.
-  if (!checked.insert(decl).second)
-    return false;
-
-  // Check an inheritance clause for a marker protocol.
-  auto checkInherited = [&](InheritedTypes inherited) -> bool {
-    for (unsigned i : inherited.getIndices()) {
-      if (auto inheritedType = inherited.getResolvedType(i)) {
-        if (inheritedType->isExistentialType()) {
-          auto layout = inheritedType->getExistentialLayout();
-          for (ProtocolDecl *proto : layout.getProtocols()) {
-            if (usesFeatureRethrowsProtocol(proto, checked))
-              return true;
-          }
-        }
-      }
-    }
-
-    return false;
-  };
-
-  if (auto nominal = dyn_cast<NominalTypeDecl>(decl)) {
-    if (checkInherited(nominal->getInherited()))
-      return true;
-  }
-
-  if (auto proto = dyn_cast<ProtocolDecl>(decl)) {
-    if (proto->getAttrs().hasAttribute<AtRethrowsAttr>())
-      return true;
-  }
-
-  if (auto ext = dyn_cast<ExtensionDecl>(decl)) {
-    if (auto nominal = ext->getSelfNominalTypeDecl())
-      if (usesFeatureRethrowsProtocol(nominal, checked))
-        return true;
-
-    if (checkInherited(ext->getInherited()))
-      return true;
-  }
-
-  if (auto genericSig =
-          decl->getInnermostDeclContext()->getGenericSignatureOfContext()) {
-    for (const auto &req : genericSig.getRequirements()) {
-      if (req.getKind() == RequirementKind::Conformance &&
-          usesFeatureRethrowsProtocol(req.getProtocolDecl(), checked))
-        return true;
-    }
-  }
-
-  if (auto value = dyn_cast<ValueDecl>(decl)) {
-    if (Type type = value->getInterfaceType()) {
-      bool hasRethrowsProtocol = type.findIf([&](Type type) {
-        if (auto nominal = type->getAnyNominal()) {
-          if (usesFeatureRethrowsProtocol(nominal, checked))
-            return true;
-        }
-
-        return false;
-      });
-
-      if (hasRethrowsProtocol)
-        return true;
-    }
-  }
-
-  return false;
-}
-
-static bool usesFeatureRethrowsProtocol(Decl *decl) {
-  SmallPtrSet<Decl *, 16> checked;
-  return usesFeatureRethrowsProtocol(decl, checked);
-}
-
 static bool usesFeatureNewCxxMethodSafetyHeuristics(Decl *decl) {
   return decl->hasClangNode();
 }

test/ModuleInterface/features.swift

@@ -81,39 +81,33 @@ public class OldSchool2: MP {
   public func takeClass() async { }
 }
 
-// CHECK:      #if compiler(>=5.3) && $RethrowsProtocol
-// CHECK-NEXT: @rethrows public protocol RP
+// CHECK: @rethrows public protocol RP
 @rethrows public protocol RP {
   func f() throws -> Bool
 }
 
 // CHECK: public struct UsesRP {
 public struct UsesRP {
-  // CHECK:     #if compiler(>=5.3) && $RethrowsProtocol
-  // CHECK-NEXT:  public var value: (any FeatureTest.RP)? {
-  // CHECK-NOT: #if compiler(>=5.3) && $RethrowsProtocol
-  // CHECK:         get
+  // CHECK:  public var value: (any FeatureTest.RP)? {
+  // CHECK-NEXT:  get
   public var value: RP? {
     nil
   }
 }
 
-// CHECK:      #if compiler(>=5.3) && $RethrowsProtocol
-// CHECK-NEXT: public struct IsRP
+// CHECK: public struct IsRP
 public struct IsRP: RP {
   // CHECK-NEXT: public func f()
   public func f() -> Bool { }
 
-  // CHECK-NOT: $RethrowsProtocol
   // CHECK-NEXT: public var isF:
   // CHECK-NEXT:   get
   public var isF: Bool {
     f()
   }
 }
 
-// CHECK: #if compiler(>=5.3) && $RethrowsProtocol
-// CHECK-NEXT: public func acceptsRP
+// CHECK: public func acceptsRP
 public func acceptsRP<T: RP>(_: T) { }
 
 // CHECK:     extension Swift.Array : FeatureTest.MP where Element : FeatureTest.MP {