Merge pull request #29237 from brentdax/revenge-of-the-synth

Revert "Merge pull request #28665 from CodaFi/the-phantom-menace"

Author: beccadax

include/swift/AST/Attr.def

@@ -535,11 +535,7 @@ DECL_ATTR(derivative, Derivative,
   ABIStableToAdd | ABIBreakingToRemove | APIStableToAdd | APIBreakingToRemove,
   97)
 
-DECL_ATTR(_implicitly_synthesizes_nested_requirement, ImplicitlySynthesizesNestedRequirement,
-  OnProtocol |
-  UserInaccessible |
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
-  98)
+// NOTE: 98 is unused
 
 DECL_ATTR(transpose, Transpose,
   OnFunc | LongAttribute | AllowMultipleAttributes |

include/swift/AST/Attr.h

@@ -685,23 +685,6 @@ class SwiftNativeObjCRuntimeBaseAttr : public DeclAttribute {
   }
 };
 
-/// Defines the @_implicitly_synthesizes_nested_requirement attribute.
-class ImplicitlySynthesizesNestedRequirementAttr : public DeclAttribute {
-public:
-  ImplicitlySynthesizesNestedRequirementAttr(StringRef Value, SourceLoc AtLoc,
-                                             SourceRange Range)
-    : DeclAttribute(DAK_ImplicitlySynthesizesNestedRequirement,
-                    AtLoc, Range, /*Implicit*/false),
-      Value(Value) {}
-
-  /// The name of the phantom requirement.
-  const StringRef Value;
-
-  static bool classof(const DeclAttribute *DA) {
-    return DA->getKind() == DAK_ImplicitlySynthesizesNestedRequirement;
-  }
-};
-
 /// Determine the result of comparing an availability attribute to a specific
 /// platform or language version.
 enum class AvailableVersionComparison {

include/swift/AST/Decl.h

@@ -476,15 +476,11 @@ class alignas(1 << DeclAlignInBits) Decl {
     IsDebuggerAlias : 1
   );
 
-  SWIFT_INLINE_BITFIELD(NominalTypeDecl, GenericTypeDecl, 1+1+1+1,
+  SWIFT_INLINE_BITFIELD(NominalTypeDecl, GenericTypeDecl, 1+1+1,
     /// Whether we have already added implicitly-defined initializers
     /// to this declaration.
     AddedImplicitInitializers : 1,
 
-    /// Whether we have already added the phantom CodingKeys
-    /// nested requirement to this declaration.
-    AddedPhantomCodingKeys : 1,
-
     /// Whether there is are lazily-loaded conformances for this nominal type.
     HasLazyConformances : 1,
 
@@ -3340,7 +3336,6 @@ class NominalTypeDecl : public GenericTypeDecl, public IterableDeclContext {
     IterableDeclContext(IterableDeclContextKind::NominalTypeDecl)
   {
     Bits.NominalTypeDecl.AddedImplicitInitializers = false;
-    Bits.NominalTypeDecl.AddedPhantomCodingKeys = false;
     ExtensionGeneration = 0;
     Bits.NominalTypeDecl.HasLazyConformances = false;
     Bits.NominalTypeDecl.IsComputingSemanticMembers = false;
@@ -3381,18 +3376,6 @@ class NominalTypeDecl : public GenericTypeDecl, public IterableDeclContext {
     Bits.NominalTypeDecl.AddedImplicitInitializers = true;
   }
 
-  /// Determine whether we have already attempted to add the
-  /// phantom CodingKeys type to this declaration.
-  bool addedPhantomCodingKeys() const {
-    return Bits.NominalTypeDecl.AddedPhantomCodingKeys;
-  }
-
-  /// Note that we have attempted to add the phantom CodingKeys type
-  /// to this declaration.
-  void setAddedPhantomCodingKeys() {
-    Bits.NominalTypeDecl.AddedPhantomCodingKeys = true;
-  }
-
   /// getDeclaredType - Retrieve the type declared by this entity, without
   /// any generic parameters bound if this is a generic type.
   Type getDeclaredType() const;

include/swift/AST/PrintOptions.h

@@ -296,8 +296,7 @@ struct PrintOptions {
   /// List of attribute kinds that should not be printed.
   std::vector<AnyAttrKind> ExcludeAttrList = {DAK_Transparent, DAK_Effects,
                                               DAK_FixedLayout,
-                                              DAK_ShowInInterface,
-                                              DAK_ImplicitlySynthesizesNestedRequirement};
+                                              DAK_ShowInInterface};
 
   /// List of attribute kinds that should be printed exclusively.
   /// Empty means allow all.

include/swift/AST/TypeCheckRequests.h

@@ -1682,6 +1682,8 @@ class InheritsSuperclassInitializersRequest
 enum class ImplicitMemberAction : uint8_t {
   ResolveImplicitInit,
   ResolveCodingKeys,
+  ResolveEncodable,
+  ResolveDecodable,
 };
 
 class ResolveImplicitMemberRequest

lib/AST/Attr.cpp

@@ -958,11 +958,6 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
     break;
   }
 
-  case DAK_ImplicitlySynthesizesNestedRequirement:
-    Printer.printAttrName("@_implicitly_synthesizes_nested_requirement");
-    Printer << "(\"" << cast<ImplicitlySynthesizesNestedRequirementAttr>(this)->Value << "\")";
-    break;
-
   case DAK_Count:
     llvm_unreachable("exceed declaration attribute kinds");
 
@@ -1024,8 +1019,6 @@ StringRef DeclAttribute::getAttrName() const {
     return "_swift_native_objc_runtime_base";
   case DAK_Semantics:
     return "_semantics";
-  case DAK_ImplicitlySynthesizesNestedRequirement:
-    return "_implicitly_synthesizes_nested_requirement";
   case DAK_Available:
     return "availability";
   case DAK_ObjC:

lib/AST/Decl.cpp

@@ -4047,6 +4047,19 @@ void NominalTypeDecl::synthesizeSemanticMembersIfNeeded(DeclName member) {
     if (baseName.getIdentifier() == getASTContext().Id_CodingKeys) {
       action.emplace(ImplicitMemberAction::ResolveCodingKeys);
     }
+  } else {
+    auto argumentNames = member.getArgumentNames();
+    if (!member.isCompoundName() || argumentNames.size() == 1) {
+      if (baseName == DeclBaseName::createConstructor() &&
+          (member.isSimpleName() || argumentNames.front() == Context.Id_from)) {
+        action.emplace(ImplicitMemberAction::ResolveDecodable);
+      } else if (!baseName.isSpecial() &&
+                 baseName.getIdentifier() == Context.Id_encode &&
+                 (member.isSimpleName() ||
+                  argumentNames.front() == Context.Id_to)) {
+        action.emplace(ImplicitMemberAction::ResolveEncodable);
+      }
+    }
   }
 
   if (auto actionToTake = action) {

lib/AST/TypeCheckRequests.cpp

@@ -1074,6 +1074,12 @@ void swift::simple_display(llvm::raw_ostream &out,
   case ImplicitMemberAction::ResolveCodingKeys:
     out << "resolve CodingKeys";
     break;
+  case ImplicitMemberAction::ResolveEncodable:
+    out << "resolve Encodable.encode(to:)";
+    break;
+  case ImplicitMemberAction::ResolveDecodable:
+    out << "resolve Decodable.init(from:)";
+    break;
   }
 }
 

lib/Parse/ParseDecl.cpp

@@ -1867,43 +1867,6 @@ bool Parser::parseNewDeclAttribute(DeclAttributes &Attributes, SourceLoc AtLoc,
     }
     break;
   }
-
-  case DAK_ImplicitlySynthesizesNestedRequirement: {
-    if (!consumeIf(tok::l_paren)) {
-      diagnose(Loc, diag::attr_expected_lparen, AttrName,
-               DeclAttribute::isDeclModifier(DK));
-      return false;
-    }
-
-    if (Tok.isNot(tok::string_literal)) {
-      diagnose(Loc, diag::attr_expected_string_literal, AttrName);
-      return false;
-    }
-
-    auto Value = getStringLiteralIfNotInterpolated(
-        Loc, ("'" + AttrName + "'").str());
-
-    consumeToken(tok::string_literal);
-
-    if (Value.hasValue())
-      AttrRange = SourceRange(Loc, Tok.getRange().getStart());
-    else
-      DiscardAttribute = true;
-
-    if (!consumeIf(tok::r_paren)) {
-      diagnose(Loc, diag::attr_expected_rparen, AttrName,
-               DeclAttribute::isDeclModifier(DK));
-      return false;
-    }
-
-    if (!DiscardAttribute) {
-      Attributes.add(new (Context)
-                     ImplicitlySynthesizesNestedRequirementAttr(Value.getValue(), AtLoc,
-                                                   AttrRange));
-    }
-    break;
-  }
-
   case DAK_Available: {
     if (!consumeIf(tok::l_paren)) {
       diagnose(Loc, diag::attr_expected_lparen, AttrName,

lib/Sema/CodeSynthesis.cpp

@@ -1076,8 +1076,11 @@ ResolveImplicitMemberRequest::evaluate(Evaluator &evaluator,
   // FIXME: This entire request is a layering violation made of smaller,
   // finickier layering violations. See rdar://56844567
 
-  auto &Context = target->getASTContext();
-  auto tryToInstallCodingKeys = [&](ProtocolDecl *protocol) {
+  // Checks whether the target conforms to the given protocol. If the
+  // conformance is incomplete, force the conformance.
+  //
+  // Returns whether the target conforms to the protocol.
+  auto evaluateTargetConformanceTo = [&](ProtocolDecl *protocol) {
     if (!protocol)
       return false;
 
@@ -1100,6 +1103,7 @@ ResolveImplicitMemberRequest::evaluate(Evaluator &evaluator,
     return true;
   };
 
+  auto &Context = target->getASTContext();
   switch (action) {
   case ImplicitMemberAction::ResolveImplicitInit:
     TypeChecker::addImplicitConstructors(target);
@@ -1117,11 +1121,30 @@ ResolveImplicitMemberRequest::evaluate(Evaluator &evaluator,
     // synthesized, it will be synthesized.
     auto *decodableProto = Context.getProtocol(KnownProtocolKind::Decodable);
     auto *encodableProto = Context.getProtocol(KnownProtocolKind::Encodable);
-    if (!tryToInstallCodingKeys(decodableProto)) {
-      (void)tryToInstallCodingKeys(encodableProto);
+    if (!evaluateTargetConformanceTo(decodableProto)) {
+      (void)evaluateTargetConformanceTo(encodableProto);
     }
   }
     break;
+  case ImplicitMemberAction::ResolveEncodable: {
+    // encode(to:) may be synthesized as part of derived conformance to the
+    // Encodable protocol.
+    // If the target should conform to the Encodable protocol, check the
+    // conformance here to attempt synthesis.
+    auto *encodableProto = Context.getProtocol(KnownProtocolKind::Encodable);
+    (void)evaluateTargetConformanceTo(encodableProto);
+  }
+    break;
+  case ImplicitMemberAction::ResolveDecodable: {
+    // init(from:) may be synthesized as part of derived conformance to the
+    // Decodable protocol.
+    // If the target should conform to the Decodable protocol, check the
+    // conformance here to attempt synthesis.
+    TypeChecker::addImplicitConstructors(target);
+    auto *decodableProto = Context.getProtocol(KnownProtocolKind::Decodable);
+    (void)evaluateTargetConformanceTo(decodableProto);
+  }
+    break;
   }
   return true;
 }