[IDE][SourceKit/DocSupport] Add members of underscored protocol extensions in extensions of conforming types.

We would previously hide the protocol, its extensions and members, but the '_'
prefix really just means the protocol itself isn't intended for clients, rather
than its members.

This also adds support for 'fully_annotated_decl' entries in doc-info for
extensions to be consistent with every other decl, and removes the
'fully_annotated_generic_signature' entry we supplied as a fallback.

Also fixes several bugs with the synthesized extensions mechanism:
- The type sustitutions applied to the extension's requirements were computed
  using the extension itself as the decl context rather than the extension's
  nominal. The meant the extension's requirements themselves were assumed to
  hold when determining the substitutions, so equality constraints were always
  met. Because of this extension members were incorrectly merged with the base
  nominal or its extensions despite having additional constraints.
- Types within the requirements weren't being transformed when printed (e.g.
  'Self.Element' was printed rather than 'T') both in the interface output and
  in the requirements list. We were also incorrectly printing requirements
  that were already satisfied once the base type was subsituted in.
- If both the protocol extension and 'enabling' extension of the base nominal
  that added the protocol conformance had conditional requirements, we were
  only printing the protocol extension's requirements in the synthesized
  extension.
- The USR and annotated decl output embedded in the 'key.doc.full_as_xml'
  string for synthesized members were printed to match their original context, rather than
  the synthesized one.

Resolves rdar://problem/57121937

Author: Nathan Hawes

include/swift/IDE/CommentConversion.h

@@ -14,6 +14,7 @@
 #define SWIFT_IDE_COMMENT_CONVERSION_H
 
 #include "swift/Basic/LLVM.h"
+#include "swift/AST/TypeOrExtensionDecl.h"
 #include <memory>
 #include <string>
 
@@ -27,7 +28,9 @@ namespace ide {
 /// in Clang-like XML format.
 ///
 /// \returns true if the declaration has a documentation comment.
-bool getDocumentationCommentAsXML(const Decl *D, raw_ostream &OS);
+bool getDocumentationCommentAsXML(
+  const Decl *D, raw_ostream &OS,
+  TypeOrExtensionDecl SynthesizedTarget = TypeOrExtensionDecl());
 
 /// If the declaration has a documentation comment and a localization key,
 /// print it into the given output stream and return true. Else, return false.

lib/AST/ASTPrinter.cpp

@@ -813,6 +813,10 @@ class PrintAST : public ASTVisitor<PrintAST> {
       TypeArrayView<GenericTypeParamType> genericParams,
       ArrayRef<Requirement> requirements, unsigned flags,
       llvm::function_ref<bool(const Requirement &)> filter);
+  void printSingleDepthOfGenericSignature(
+      TypeArrayView<GenericTypeParamType> genericParams,
+      ArrayRef<Requirement> requirements, bool &isFirstReq, unsigned flags,
+      llvm::function_ref<bool(const Requirement &)> filter);
   void printRequirement(const Requirement &req);
 
 private:
@@ -872,7 +876,12 @@ class PrintAST : public ASTVisitor<PrintAST> {
       return false; // not needed for the parser library.
     #endif
 
-    if (!shouldPrint(D, true))
+    bool Synthesize =
+        Options.TransformContext &&
+        Options.TransformContext->isPrintingSynthesizedExtension() &&
+        isa<ExtensionDecl>(D);
+
+    if (!shouldPrint(D, true) && !Synthesize)
       return false;
 
     Decl *Old = Current;
@@ -890,10 +899,6 @@ class PrintAST : public ASTVisitor<PrintAST> {
 
     SWIFT_DEFER { CurrentType = OldType; };
 
-    bool Synthesize =
-        Options.TransformContext &&
-        Options.TransformContext->isPrintingSynthesizedExtension() &&
-        isa<ExtensionDecl>(D);
     if (Synthesize) {
       Printer.setSynthesizedTarget(Options.TransformContext->getDecl());
     }
@@ -1456,6 +1461,15 @@ void PrintAST::printSingleDepthOfGenericSignature(
     TypeArrayView<GenericTypeParamType> genericParams,
     ArrayRef<Requirement> requirements, unsigned flags,
     llvm::function_ref<bool(const Requirement &)> filter) {
+  bool isFirstReq = true;
+  printSingleDepthOfGenericSignature(genericParams, requirements, isFirstReq,
+                                     flags, filter);
+}
+
+void PrintAST::printSingleDepthOfGenericSignature(
+    TypeArrayView<GenericTypeParamType> genericParams,
+    ArrayRef<Requirement> requirements, bool &isFirstReq, unsigned flags,
+    llvm::function_ref<bool(const Requirement &)> filter) {
   bool printParams = (flags & PrintParams);
   bool printRequirements = (flags & PrintRequirements);
   printRequirements &= Options.PrintGenericRequirements;
@@ -1502,7 +1516,6 @@ void PrintAST::printSingleDepthOfGenericSignature(
   }
 
   if (printRequirements || printInherited) {
-    bool isFirstReq = true;
     for (const auto &req : requirements) {
       if (!filter(req))
         continue;
@@ -1564,9 +1577,6 @@ void PrintAST::printSingleDepthOfGenericSignature(
         }
       } else {
         Printer.callPrintStructurePre(PrintStructureKind::GenericRequirement);
-
-        // We don't substitute type for the printed requirement so that the
-        // printed requirement agrees with separately reported generic parameters.
         printRequirement(req);
         Printer.printStructurePost(PrintStructureKind::GenericRequirement);
       }
@@ -1578,7 +1588,7 @@ void PrintAST::printSingleDepthOfGenericSignature(
 }
 
 void PrintAST::printRequirement(const Requirement &req) {
-  printType(req.getFirstType());
+  printTransformedType(req.getFirstType());
   switch (req.getKind()) {
   case RequirementKind::Layout:
     Printer << " : ";
@@ -1592,7 +1602,7 @@ void PrintAST::printRequirement(const Requirement &req) {
     Printer << " == ";
     break;
   }
-  printType(req.getSecondType());
+  printTransformedType(req.getSecondType());
 }
 
 bool PrintAST::shouldPrintPattern(const Pattern *P) {
@@ -2180,16 +2190,78 @@ static void printExtendedTypeName(Type ExtendedType, ASTPrinter &Printer,
   Ty->print(Printer, Options);
 }
 
+
 void PrintAST::printSynthesizedExtension(Type ExtendedType,
                                          ExtensionDecl *ExtDecl) {
+
+  auto printRequirementsFrom = [&](ExtensionDecl *ED, bool &IsFirst) {
+    auto Sig = ED->getGenericSignature();
+    printSingleDepthOfGenericSignature(Sig->getGenericParams(),
+                                       Sig->getRequirements(),
+                                       IsFirst, PrintRequirements,
+                                       [](const Requirement &Req){
+      return true;
+    });
+  };
+
+  auto printCombinedRequirementsIfNeeded = [&]() -> bool {
+    if (!Options.TransformContext ||
+        !Options.TransformContext->isPrintingSynthesizedExtension())
+      return false;
+
+    // Combined requirements only needed if the transform context is an enabling
+    // extension of the protocol rather than a nominal (which can't have
+    // constraints of its own).
+    ExtensionDecl *Target = dyn_cast<ExtensionDecl>(
+      Options.TransformContext->getDecl().getAsDecl());
+    if (!Target || Target == ExtDecl)
+      return false;
+
+    bool IsFirst = true;
+    if (ExtDecl->isConstrainedExtension()) {
+      printRequirementsFrom(ExtDecl, IsFirst);
+    }
+    if (Target->isConstrainedExtension()) {
+      if (auto *NTD = Target->getExtendedNominal()) {
+        // Update the current decl and type transform for Target rather than
+        // ExtDecl.
+        PrintOptions Adjusted = Options;
+        Adjusted.initForSynthesizedExtension(NTD);
+        llvm::SaveAndRestore<Decl*> TempCurrent(Current, NTD);
+        llvm::SaveAndRestore<PrintOptions> TempOptions(Options, Adjusted);
+        printRequirementsFrom(Target, IsFirst);
+      }
+    }
+    return true;
+  };
+
+
   if (Options.BracketOptions.shouldOpenExtension(ExtDecl)) {
     printDocumentationComment(ExtDecl);
     printAttributes(ExtDecl);
     Printer << tok::kw_extension << " ";
 
     printExtendedTypeName(ExtendedType, Printer, Options);
     printInherited(ExtDecl);
-    printDeclGenericRequirements(ExtDecl);
+
+    // We may need to combine requirements from ExtDecl (which has the members
+    // to print) and the TransformContexts' decl if it is an enabling extension
+    // of the base NominalDecl (which can have its own requirements) rather than
+    // base NominalDecl itself (which can't). E.g:
+    //
+    //   protocol Foo {}
+    //   extension Foo where <requirments from ExtDecl> { ... }
+    //   struct Bar {}
+    //   extension Bar: Foo where <requirments from TransformContext> { ... }
+    //
+    // should produce a synthesized extension of Bar with both sets of
+    // requirments:
+    //
+    //   extension Bar where <requirments from ExtDecl+TransformContext { ... }
+    //
+    if (!printCombinedRequirementsIfNeeded())
+      printDeclGenericRequirements(ExtDecl);
+
   }
   if (Options.TypeDefinitions) {
     printMembersOfDecl(ExtDecl, false,

lib/IDE/CommentConversion.cpp

@@ -258,7 +258,7 @@ struct CommentToXMLConverter {
     OS << "</Tags>";
   }
 
-  void visitDocComment(const DocComment *DC);
+  void visitDocComment(const DocComment *DC, TypeOrExtensionDecl SynthesizedTarget);
   void visitCommentParts(const swift::markup::CommentParts &Parts);
 };
 } // unnamed namespace
@@ -297,7 +297,8 @@ void CommentToXMLConverter::visitCommentParts(const swift::markup::CommentParts
   }
 }
 
-void CommentToXMLConverter::visitDocComment(const DocComment *DC) {
+void CommentToXMLConverter::
+visitDocComment(const DocComment *DC, TypeOrExtensionDecl SynthesizedTarget) {
   const Decl *D = DC->getDecl();
 
   StringRef RootEndTag;
@@ -347,6 +348,10 @@ void CommentToXMLConverter::visitDocComment(const DocComment *DC) {
     {
       llvm::raw_svector_ostream OS(SS);
       Failed = ide::printValueDeclUSR(VD, OS);
+      if (!Failed && SynthesizedTarget) {
+        OS << "::SYNTHESIZED::";
+        Failed = ide::printValueDeclUSR(SynthesizedTarget.getBaseNominal(), OS);
+      }
     }
     if (!Failed && !SS.empty()) {
       OS << "<USR>" << SS << "</USR>";
@@ -362,6 +367,9 @@ void CommentToXMLConverter::visitDocComment(const DocComment *DC) {
     PO.VarInitializers = false;
     PO.ShouldQualifyNestedDeclarations =
         PrintOptions::QualifyNestedDeclarations::TypesOnly;
+    PO.SkipUnderscoredStdlibProtocols = false;
+    if (SynthesizedTarget)
+      PO.initForSynthesizedExtension(SynthesizedTarget);
 
     OS << "<Declaration>";
     llvm::SmallString<32> DeclSS;
@@ -398,12 +406,15 @@ static bool getClangDocumentationCommentAsXML(const clang::Decl *D,
   return true;
 }
 
-static void replaceObjcDeclarationsWithSwiftOnes(const Decl *D,
-                                                       StringRef Doc,
-                                                       raw_ostream &OS) {
+static void
+replaceObjcDeclarationsWithSwiftOnes(const Decl *D, StringRef Doc,
+                                     raw_ostream &OS,
+                                     TypeOrExtensionDecl SynthesizedTarget) {
   StringRef Open = "<Declaration>";
   StringRef Close = "</Declaration>";
   PrintOptions Options = PrintOptions::printQuickHelpDeclaration();
+  if (SynthesizedTarget)
+      Options.initForSynthesizedExtension(SynthesizedTarget);
   std::string S;
   llvm::raw_string_ostream SS(S);
   D->print(SS, Options);
@@ -444,14 +455,16 @@ std::string ide::extractPlainTextFromComment(const StringRef Text) {
   return getLineListFromComment(SourceMgr, MC, Text).str();
 }
 
-bool ide::getDocumentationCommentAsXML(const Decl *D, raw_ostream &OS) {
+bool ide::getDocumentationCommentAsXML(const Decl *D, raw_ostream &OS,
+                                       TypeOrExtensionDecl SynthesizedTarget) {
   auto MaybeClangNode = D->getClangNode();
   if (MaybeClangNode) {
     if (auto *CD = MaybeClangNode.getAsDecl()) {
       std::string S;
       llvm::raw_string_ostream SS(S);
       if (getClangDocumentationCommentAsXML(CD, SS)) {
-        replaceObjcDeclarationsWithSwiftOnes(D, SS.str(), OS);
+        replaceObjcDeclarationsWithSwiftOnes(D, SS.str(), OS,
+                                             SynthesizedTarget);
         return true;
       }
     }
@@ -464,7 +477,7 @@ bool ide::getDocumentationCommentAsXML(const Decl *D, raw_ostream &OS) {
     return false;
 
   CommentToXMLConverter Converter(OS);
-  Converter.visitDocComment(DC);
+  Converter.visitDocComment(DC, SynthesizedTarget);
 
   OS.flush();
   return true;

lib/IDE/IDETypeChecking.cpp

@@ -282,16 +282,27 @@ struct SynthesizedExtensionAnalyzer::Implementation {
 
     auto handleRequirements = [&](SubstitutionMap subMap,
                                   GenericSignature GenericSig,
+                                  ExtensionDecl *OwningExt,
                                   ArrayRef<Requirement> Reqs) {
+      ProtocolDecl *BaseProto = OwningExt->getInnermostDeclContext()
+        ->getSelfProtocolDecl();
       for (auto Req : Reqs) {
         auto Kind = Req.getKind();
 
         // FIXME: Could do something here
         if (Kind == RequirementKind::Layout)
           continue;
 
-        auto First = Req.getFirstType();
-        auto Second = Req.getSecondType();
+        Type First = Req.getFirstType();
+        Type Second = Req.getSecondType();
+
+        // Skip protocol's Self : <Protocol> requirement.
+        if (BaseProto &&
+            Req.getKind() == RequirementKind::Conformance &&
+            First->isEqual(BaseProto->getSelfInterfaceType()) &&
+            Second->getAnyNominal() == BaseProto)
+          continue;
+
         if (!BaseType->isExistentialType()) {
           First = First.subst(subMap);
           Second = Second.subst(subMap);
@@ -346,19 +357,29 @@ struct SynthesizedExtensionAnalyzer::Implementation {
       // the extension to the interface types of the base type's
       // declaration.
       SubstitutionMap subMap;
-      if (!BaseType->isExistentialType())
-        subMap = BaseType->getContextSubstitutionMap(M, Ext);
+      if (!BaseType->isExistentialType()) {
+        if (auto *NTD = Ext->getExtendedNominal())
+          subMap = BaseType->getContextSubstitutionMap(M, NTD);
+      }
 
       assert(Ext->getGenericSignature() && "No generic signature.");
       auto GenericSig = Ext->getGenericSignature();
-      if (handleRequirements(subMap, GenericSig, GenericSig->getRequirements()))
+      if (handleRequirements(subMap, GenericSig, Ext, GenericSig->getRequirements()))
         return {Result, MergeInfo};
     }
 
-    if (Conf && handleRequirements(Conf->getSubstitutions(M),
-                                   Conf->getGenericSignature(),
-                                   Conf->getConditionalRequirements()))
-      return {Result, MergeInfo};
+    if (Conf) {
+      SubstitutionMap subMap;
+      if (!BaseType->isExistentialType()) {
+        if (auto *NTD = EnablingExt->getExtendedNominal())
+          subMap = BaseType->getContextSubstitutionMap(M, NTD);
+      }
+      if (handleRequirements(subMap,
+                             Conf->getGenericSignature(),
+                             EnablingExt,
+                             Conf->getConditionalRequirements()))
+        return {Result, MergeInfo};
+    }
 
     Result.Ext = Ext;
     return {Result, MergeInfo};
@@ -431,7 +452,14 @@ struct SynthesizedExtensionAnalyzer::Implementation {
     auto handleExtension = [&](ExtensionDecl *E, bool Synthesized,
                                ExtensionDecl *EnablingE,
                                NormalProtocolConformance *Conf) {
-      if (Options.shouldPrint(E)) {
+      PrintOptions AdjustedOpts = Options;
+      if (Synthesized) {
+        // Members from underscored system protocols should still appear as
+        // members of the target type, even if the protocols themselves are not
+        // printed.
+        AdjustedOpts.SkipUnderscoredStdlibProtocols = false;
+      }
+      if (AdjustedOpts.shouldPrint(E)) {
         auto Pair = isApplicable(E, Synthesized, EnablingE, Conf);
         if (Pair.first) {
           InfoMap->insert({E, Pair.first});

test/IDE/print_synthesized_extensions.swift

@@ -237,21 +237,21 @@ extension S13 : P5 {
   public func foo1() {}
 }
 
-// CHECK1: <synthesized>extension <ref:Struct>S1</ref> where <ref:GenericTypeParam>Self</ref>.P2T1 : <ref:Protocol>P2</ref> {
+// CHECK1: <synthesized>extension <ref:Struct>S1</ref> where T : <ref:Protocol>P2</ref> {
 // CHECK1-NEXT:     <decl:Func>public func <loc>p2member()</loc></decl>
 // CHECK1-NEXT:     <decl:Func>public func <loc>ef1(<decl:Param>t: T</decl>)</loc></decl>
 // CHECK1-NEXT:     <decl:Func>public func <loc>ef2(<decl:Param>t: <ref:Struct>S2</ref></decl>)</loc></decl>
 // CHECK1-NEXT: }</synthesized>
 
-// CHECK2:  <synthesized>extension <ref:Struct>S1</ref> where <ref:GenericTypeParam>Self</ref>.T1 : <ref:Protocol>P3</ref>  {
+// CHECK2:  <synthesized>extension <ref:Struct>S1</ref> where T : <ref:Protocol>P3</ref>  {
 // CHECK2-NEXT:     <decl:Func>public func <loc>p3Func(<decl:Param>i: <ref:Struct>Int</ref></decl>)</loc> -> <ref:Struct>Int</ref></decl>
 // CHECK2-NEXT: }</synthesized>
 
-// CHECK3:  <synthesized>extension <ref:Struct>S1</ref> where <ref:GenericTypeParam>Self</ref>.T1 == <ref:Struct>Int</ref>  {
+// CHECK3:  <synthesized>extension <ref:Struct>S1</ref> where T == <ref:Struct>Int</ref>  {
 // CHECK3-NEXT:     <decl:Func>public func <loc>p1IntFunc(<decl:Param>i: <ref:Struct>Int</ref></decl>)</loc> -> <ref:Struct>Int</ref></decl>
 // CHECK3-NEXT: }</synthesized>
 
-// CHECK4:  <synthesized>extension <ref:Struct>S1</ref> where <ref:GenericTypeParam>Self</ref>.T1 == <ref:Struct>S9</ref><<ref:Struct>Int</ref>> {
+// CHECK4:  <synthesized>extension <ref:Struct>S1</ref> where T == <ref:Struct>S9</ref><<ref:Struct>Int</ref>> {
 // CHECK4-NEXT:     <decl:Func>public func <loc>S9IntFunc()</loc></decl>
 // CHECK4-NEXT: }</synthesized>