Merge pull request #22429 from rintaro/sourcekit-conformingmethods

[IDE/SourceKit] New SourceKit request for filtered method list
2025-12-14 20:36:38 +01:00 · 2019-02-11 18:13:15 -08:00
parent 08484a8beb bbf288b53f
commit 552dcd81aa
24 changed files with 1040 additions and 210 deletions
--- a/include/swift/IDE/ConformingMethodList.h
+++ b/include/swift/IDE/ConformingMethodList.h
@@ -0,0 +1,66 @@
+//===--- ConformingMethodList.h --- -----------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2019 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
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_IDE_CONFORMINGMETHODLIST_H
+#define SWIFT_IDE_CONFORMINGMETHODLIST_H
+
+#include "swift/AST/Type.h"
+#include "swift/Basic/LLVM.h"
+
+namespace swift {
+class CodeCompletionCallbacksFactory;
+
+namespace ide {
+
+/// A result item for context info query.
+class ConformingMethodListResult {
+public:
+  /// The decl context of the parsed expression.
+  DeclContext *DC;
+
+  /// The resolved type of the expression.
+  Type ExprType;
+
+  /// Methods which satisfy the criteria.
+  SmallVector<ValueDecl *, 0> Members;
+
+  ConformingMethodListResult(DeclContext *DC, Type ExprType)
+      : DC(DC), ExprType(ExprType) {}
+};
+
+/// An abstract base class for consumers of context info results.
+class ConformingMethodListConsumer {
+public:
+  virtual ~ConformingMethodListConsumer() {}
+  virtual void handleResult(const ConformingMethodListResult &result) = 0;
+};
+
+/// Printing consumer
+class PrintingConformingMethodListConsumer
+    : public ConformingMethodListConsumer {
+  llvm::raw_ostream &OS;
+
+public:
+  PrintingConformingMethodListConsumer(llvm::raw_ostream &OS) : OS(OS) {}
+
+  void handleResult(const ConformingMethodListResult &result) override;
+};
+
+/// Create a factory for code completion callbacks.
+CodeCompletionCallbacksFactory *makeConformingMethodListCallbacksFactory(
+    ArrayRef<const char *> expectedTypeNames,
+    ConformingMethodListConsumer &Consumer);
+
+} // namespace ide
+} // namespace swift
+
+#endif // SWIFT_IDE_CONFORMINGMETHODLIST_H
--- a/include/swift/Parse/CodeCompletionCallbacks.h
+++ b/include/swift/Parse/CodeCompletionCallbacks.h
@@ -117,35 +117,35 @@ public:

  /// Complete the whole expression.  This is a fallback that should
  /// produce results when more specific completion methods failed.
-  virtual void completeExpr() = 0;
+  virtual void completeExpr() {};

  /// Complete expr-dot after we have consumed the dot.
-  virtual void completeDotExpr(Expr *E, SourceLoc DotLoc) = 0;
+  virtual void completeDotExpr(Expr *E, SourceLoc DotLoc) {};

  /// Complete the beginning of a statement or expression.
-  virtual void completeStmtOrExpr() = 0;
+  virtual void completeStmtOrExpr() {};

  /// Complete the beginning of expr-postfix -- no tokens provided
  /// by user.
-  virtual void completePostfixExprBeginning(CodeCompletionExpr *E) = 0;
+  virtual void completePostfixExprBeginning(CodeCompletionExpr *E) {};

  /// Complete the beginning of expr-postfix in a for-each loop sequqence
  /// -- no tokens provided by user.
-  virtual void completeForEachSequenceBeginning(CodeCompletionExpr *E) = 0;
+  virtual void completeForEachSequenceBeginning(CodeCompletionExpr *E) {};

  /// Complete a given expr-postfix.
-  virtual void completePostfixExpr(Expr *E, bool hasSpace) = 0;
+  virtual void completePostfixExpr(Expr *E, bool hasSpace) {};

  /// Complete a given expr-postfix, given that there is a following
  /// left parenthesis.
-  virtual void completePostfixExprParen(Expr *E, Expr *CodeCompletionE) = 0;
+  virtual void completePostfixExprParen(Expr *E, Expr *CodeCompletionE) {};

  /// Complete expr-super after we have consumed the 'super' keyword.
-  virtual void completeExprSuper(SuperRefExpr *SRE) = 0;
+  virtual void completeExprSuper(SuperRefExpr *SRE) {};

  /// Complete expr-super after we have consumed the 'super' keyword and
  /// a dot.
-  virtual void completeExprSuperDot(SuperRefExpr *SRE) = 0;
+  virtual void completeExprSuperDot(SuperRefExpr *SRE) {};

  /// Complete the argument to an Objective-C #keyPath
  /// expression.
@@ -153,59 +153,59 @@ public:
  /// \param KPE A partial #keyPath expression that can be used to
  /// provide context. This will be \c NULL if no components of the
  /// #keyPath argument have been parsed yet.
-  virtual void completeExprKeyPath(KeyPathExpr *KPE, SourceLoc DotLoc) = 0;
+  virtual void completeExprKeyPath(KeyPathExpr *KPE, SourceLoc DotLoc) {};

  /// Complete the beginning of type-simple -- no tokens provided
  /// by user.
-  virtual void completeTypeSimpleBeginning() = 0;
+  virtual void completeTypeSimpleBeginning() {};

  /// Complete a given type-identifier after we have consumed the dot.
-  virtual void completeTypeIdentifierWithDot(IdentTypeRepr *ITR) = 0;
+  virtual void completeTypeIdentifierWithDot(IdentTypeRepr *ITR) {};

  /// Complete a given type-identifier when there is no trailing dot.
-  virtual void completeTypeIdentifierWithoutDot(IdentTypeRepr *ITR) = 0;
+  virtual void completeTypeIdentifierWithoutDot(IdentTypeRepr *ITR) {};

  /// Complete at the beginning of a case stmt pattern.
-  virtual void completeCaseStmtBeginning() = 0;
+  virtual void completeCaseStmtBeginning() {};

  /// Complete a case stmt pattern that starts with a dot.
-  virtual void completeCaseStmtDotPrefix() = 0;
+  virtual void completeCaseStmtDotPrefix() {};

  /// Complete at the beginning of member of a nominal decl member -- no tokens
  /// provided by user.
  virtual void completeNominalMemberBeginning(
-      SmallVectorImpl<StringRef> &Keywords) = 0;
+      SmallVectorImpl<StringRef> &Keywords) {};

  /// Complete at the beginning of accessor in a accessor block.
-  virtual void completeAccessorBeginning() = 0;
+  virtual void completeAccessorBeginning() {};

  /// Complete the keyword in attribute, for instance, @available.
-  virtual void completeDeclAttrKeyword(Decl *D, bool Sil, bool Param) = 0;
+  virtual void completeDeclAttrKeyword(Decl *D, bool Sil, bool Param) {};

  /// Complete the parameters in attribute, for instance, version specifier for
  /// @available.
-  virtual void completeDeclAttrParam(DeclAttrKind DK, int Index) = 0;
+  virtual void completeDeclAttrParam(DeclAttrKind DK, int Index) {};

  /// Complete within a precedence group decl or after a colon in an
  /// operator decl.
-  virtual void completeInPrecedenceGroup(SyntaxKind SK) = 0;
+  virtual void completeInPrecedenceGroup(SyntaxKind SK) {};

  /// Complete the platform names inside #available statements.
-  virtual void completePoundAvailablePlatform() = 0;
+  virtual void completePoundAvailablePlatform() {};

  /// Complete the import decl with importable modules.
  virtual void
-  completeImportDecl(std::vector<std::pair<Identifier, SourceLoc>> &Path) = 0;
+  completeImportDecl(std::vector<std::pair<Identifier, SourceLoc>> &Path) {};

  /// Complete unresolved members after dot.
  virtual void completeUnresolvedMember(CodeCompletionExpr *E,
-                                        SourceLoc DotLoc) = 0;
+                                        SourceLoc DotLoc) {};

-  virtual void completeAssignmentRHS(AssignExpr *E) = 0;
+  virtual void completeAssignmentRHS(AssignExpr *E) {};

-  virtual void completeCallArg(CodeCompletionExpr *E) = 0;
+  virtual void completeCallArg(CodeCompletionExpr *E) {};

-  virtual void completeReturnStmt(CodeCompletionExpr *E) = 0;
+  virtual void completeReturnStmt(CodeCompletionExpr *E) {};

  /// Complete a yield statement.  A missing yield index means that the
  /// completion immediately follows the 'yield' keyword; it may be either
@@ -213,18 +213,18 @@ public:
  /// index means that the completion is within the parentheses and is
  /// for a specific yield value.
  virtual void completeYieldStmt(CodeCompletionExpr *E,
-                                 Optional<unsigned> yieldIndex) = 0;
+                                 Optional<unsigned> yieldIndex) {};

  virtual void completeAfterPoundExpr(CodeCompletionExpr *E,
-                                      Optional<StmtKind> ParentKind) = 0;
+                                      Optional<StmtKind> ParentKind) {};

-  virtual void completeAfterPoundDirective() = 0;
+  virtual void completeAfterPoundDirective() {};

-  virtual void completePlatformCondition() = 0;
+  virtual void completePlatformCondition() {};

-  virtual void completeAfterIfStmt(bool hasElse) = 0;
+  virtual void completeAfterIfStmt(bool hasElse) {};

-  virtual void completeGenericParams(TypeLoc TL) = 0;
+  virtual void completeGenericParams(TypeLoc TL) {};

  /// Signals that the AST for the all the delayed-parsed code was
  /// constructed.  No \c complete*() callbacks will be done after this.
--- a/lib/IDE/CMakeLists.txt
+++ b/lib/IDE/CMakeLists.txt
@@ -2,6 +2,7 @@ add_swift_host_library(swiftIDE STATIC
  CodeCompletion.cpp
  CodeCompletionCache.cpp
  CommentConversion.cpp
+  ConformingMethodList.cpp
  ExprContextAnalysis.cpp
  Formatting.cpp
  Refactoring.cpp
--- a/lib/IDE/CodeCompletion.cpp
+++ b/lib/IDE/CodeCompletion.cpp
@@ -374,48 +374,6 @@ static Stmt *findNearestStmt(const DeclContext *DC, SourceLoc Loc,
  const_cast<DeclContext *>(DC)->walkContext(Finder);
  return Finder.getFoundStmt();
 }
-/// Prepare the given expression for type-checking again, prinicipally by
-/// erasing any ErrorType types on the given expression, allowing later
-/// type-checking to make progress.
-///
-/// FIXME: this is fundamentally a workaround for the fact that we may end up
-/// typechecking parts of an expression more than once - first for checking
-/// the context, and later for checking more-specific things like unresolved
-/// members.  We should restructure code-completion type-checking so that we
-/// never typecheck more than once (or find a more principled way to do it).
-static void prepareForRetypechecking(Expr *E) {
-  assert(E);
-  struct Eraser : public ASTWalker {
-    std::pair<bool, Expr *> walkToExprPre(Expr *expr) override {
-      if (expr && expr->getType() && (expr->getType()->hasError() ||
-                                      expr->getType()->hasUnresolvedType()))
-        expr->setType(Type());
-      if (auto *ACE = dyn_cast_or_null<AutoClosureExpr>(expr)) {
-        return { true, ACE->getSingleExpressionBody() };
-      }
-      return { true, expr };
-    }
-    bool walkToTypeLocPre(TypeLoc &TL) override {
-      if (TL.getType() && (TL.getType()->hasError() ||
-                           TL.getType()->hasUnresolvedType()))
-        TL.setType(Type());
-      return true;
-    }
-
-    std::pair<bool, Pattern*> walkToPatternPre(Pattern *P) override {
-      if (P && P->hasType() && (P->getType()->hasError() ||
-                                P->getType()->hasUnresolvedType())) {
-        P->setType(Type());
-      }
-      return { true, P };
-    }
-    std::pair<bool, Stmt *> walkToStmtPre(Stmt *S) override {
-      return { false, S };
-    }
-  };
-
-  E->walk(Eraser());
-}

 CodeCompletionString::CodeCompletionString(ArrayRef<Chunk> Chunks) {
  std::uninitialized_copy(Chunks.begin(), Chunks.end(),
--- a/lib/IDE/ConformingMethodList.cpp
+++ b/lib/IDE/ConformingMethodList.cpp
@@ -0,0 +1,241 @@
+//===--- ConformingMethodList.cpp -----------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2019 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
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/IDE/ConformingMethodList.h"
+#include "ExprContextAnalysis.h"
+#include "swift/AST/ASTDemangler.h"
+#include "swift/AST/GenericEnvironment.h"
+#include "swift/AST/NameLookup.h"
+#include "swift/AST/USRGeneration.h"
+#include "swift/Parse/CodeCompletionCallbacks.h"
+#include "swift/Sema/IDETypeChecking.h"
+#include "clang/AST/Attr.h"
+#include "clang/AST/Decl.h"
+
+using namespace swift;
+using namespace ide;
+
+namespace {
+class ConformingMethodListCallbacks : public CodeCompletionCallbacks {
+  ArrayRef<const char *> ExpectedTypeNames;
+  ConformingMethodListConsumer &Consumer;
+  SourceLoc Loc;
+  Expr *ParsedExpr = nullptr;
+  DeclContext *CurDeclContext = nullptr;
+
+  void resolveExpectedTypes(ArrayRef<const char *> names, SourceLoc loc,
+                            SmallVectorImpl<ProtocolDecl *> &result);
+  void getMatchingMethods(Type T, ArrayRef<ProtocolDecl *> expectedTypes,
+                          SmallVectorImpl<ValueDecl *> &result);
+
+public:
+  ConformingMethodListCallbacks(Parser &P,
+                                ArrayRef<const char *> ExpectedTypeNames,
+                                ConformingMethodListConsumer &Consumer)
+      : CodeCompletionCallbacks(P), ExpectedTypeNames(ExpectedTypeNames),
+        Consumer(Consumer) {}
+
+  // Only handle callbacks for suffix completions.
+  // {
+  void completeDotExpr(Expr *E, SourceLoc DotLoc) override;
+  void completePostfixExpr(Expr *E, bool hasSpace) override;
+  // }
+
+  void doneParsing() override;
+};
+
+void ConformingMethodListCallbacks::completeDotExpr(Expr *E, SourceLoc DotLoc) {
+  CurDeclContext = P.CurDeclContext;
+  ParsedExpr = E;
+}
+
+void ConformingMethodListCallbacks::completePostfixExpr(Expr *E,
+                                                        bool hasSpace) {
+  CurDeclContext = P.CurDeclContext;
+  ParsedExpr = E;
+}
+
+void ConformingMethodListCallbacks::doneParsing() {
+  if (!ParsedExpr)
+    return;
+
+  typeCheckContextUntil(
+      CurDeclContext,
+      CurDeclContext->getASTContext().SourceMgr.getCodeCompletionLoc());
+
+  Type T = ParsedExpr->getType();
+
+  // Type check the expression if needed.
+  if (!T || T->is<ErrorType>()) {
+    prepareForRetypechecking(ParsedExpr);
+    ConcreteDeclRef ReferencedDecl = nullptr;
+    auto optT = getTypeOfCompletionContextExpr(P.Context, CurDeclContext,
+                                               CompletionTypeCheckKind::Normal,
+                                               ParsedExpr, ReferencedDecl);
+    if (!optT)
+      return;
+    T = *optT;
+  }
+
+  if (!T || T->is<ErrorType>() || T->is<UnresolvedType>())
+    return;
+
+  SmallVector<ProtocolDecl *, 4> expectedProtocols;
+  resolveExpectedTypes(ExpectedTypeNames, ParsedExpr->getLoc(),
+                       expectedProtocols);
+
+  // Collect the matching methods.
+  ConformingMethodListResult result(CurDeclContext, T);
+  getMatchingMethods(T, expectedProtocols, result.Members);
+
+  Consumer.handleResult(result);
+}
+
+void ConformingMethodListCallbacks::resolveExpectedTypes(
+    ArrayRef<const char *> names, SourceLoc loc,
+    SmallVectorImpl<ProtocolDecl *> &result) {
+  auto &ctx = CurDeclContext->getASTContext();
+
+  for (auto name : names) {
+    if (auto ty = Demangle::getTypeForMangling(ctx, name)) {
+      if (auto Proto = dyn_cast_or_null<ProtocolDecl>(ty->getAnyGeneric()))
+        result.push_back(Proto);
+    }
+  }
+}
+
+void ConformingMethodListCallbacks::getMatchingMethods(
+    Type T, ArrayRef<ProtocolDecl *> expectedTypes,
+    SmallVectorImpl<ValueDecl *> &result) {
+  if (!T->mayHaveMembers())
+    return;
+
+  class LocalConsumer : public VisibleDeclConsumer {
+    ModuleDecl *CurModule;
+
+    /// The type of the parsed expression.
+    Type T;
+
+    /// The list of expected types.
+    ArrayRef<ProtocolDecl *> ExpectedTypes;
+
+    /// Result sink to populate.
+    SmallVectorImpl<ValueDecl *> &Result;
+
+    /// Returns true if \p VD is a instance method whose return type conforms
+    /// to the requested protocols.
+    bool isMatchingMethod(ValueDecl *VD) {
+      if (!isa<FuncDecl>(VD))
+        return false;
+      if (VD->isStatic() || VD->isOperator())
+        return false;
+
+      auto declTy = T->getTypeOfMember(CurModule, VD);
+      if (declTy->is<ErrorType>())
+        return false;
+
+      // Strip '(Self.Type) ->' and parameters.
+      declTy = declTy->castTo<AnyFunctionType>()->getResult();
+      declTy = declTy->castTo<AnyFunctionType>()->getResult();
+
+      // The return type conforms to any of the requested protocols.
+      for (auto Proto : ExpectedTypes) {
+        if (CurModule->conformsToProtocol(declTy, Proto))
+          return true;
+      }
+
+      return false;
+    }
+
+  public:
+    LocalConsumer(DeclContext *DC, Type T,
+                  ArrayRef<ProtocolDecl *> expectedTypes,
+                  SmallVectorImpl<ValueDecl *> &result)
+        : CurModule(DC->getParentModule()), T(T), ExpectedTypes(expectedTypes),
+          Result(result) {}
+
+    void foundDecl(ValueDecl *VD, DeclVisibilityKind reason) {
+      if (isMatchingMethod(VD) && !VD->shouldHideFromEditor())
+        Result.push_back(VD);
+    }
+
+  } LocalConsumer(CurDeclContext, T, expectedTypes, result);
+
+  lookupVisibleMemberDecls(LocalConsumer, MetatypeType::get(T), CurDeclContext,
+                           CurDeclContext->getASTContext().getLazyResolver(),
+                           /*includeInstanceMembers=*/false);
+}
+
+} // anonymous namespace.
+
+void PrintingConformingMethodListConsumer::handleResult(
+    const ConformingMethodListResult &result) {
+  OS << "-----BEGIN CONFORMING METHOD LIST-----\n";
+
+  OS << "- TypeName: ";
+  result.ExprType.print(OS);
+  OS << "\n";
+
+  OS << "- Members: ";
+  if (result.Members.empty())
+    OS << " []";
+  OS << "\n";
+  for (auto VD : result.Members) {
+    auto funcTy = cast<FuncDecl>(VD)->getMethodInterfaceType();
+    funcTy = result.ExprType->getTypeOfMember(result.DC->getParentModule(), VD,
+                                              funcTy);
+    auto resultTy = funcTy->castTo<FunctionType>()->getResult();
+
+    OS << "   - Name: ";
+    VD->getFullName().print(OS);
+    OS << "\n";
+
+    OS << "     TypeName: ";
+    resultTy.print(OS);
+    OS << "\n";
+
+    StringRef BriefDoc = VD->getBriefComment();
+    if (!BriefDoc.empty()) {
+      OS << "     DocBrief: \"";
+      OS << VD->getBriefComment();
+      OS << "\"\n";
+    }
+  }
+
+  OS << "-----END CONFORMING METHOD LIST-----\n";
+}
+
+CodeCompletionCallbacksFactory *
+swift::ide::makeConformingMethodListCallbacksFactory(
+    ArrayRef<const char *> expectedTypeNames,
+    ConformingMethodListConsumer &Consumer) {
+
+  // CC callback factory which produces 'ContextInfoCallbacks'.
+  class ConformingMethodListCallbacksFactoryImpl
+      : public CodeCompletionCallbacksFactory {
+    ArrayRef<const char *> ExpectedTypeNames;
+    ConformingMethodListConsumer &Consumer;
+
+  public:
+    ConformingMethodListCallbacksFactoryImpl(
+        ArrayRef<const char *> ExpectedTypeNames,
+        ConformingMethodListConsumer &Consumer)
+        : ExpectedTypeNames(ExpectedTypeNames), Consumer(Consumer) {}
+
+    CodeCompletionCallbacks *createCodeCompletionCallbacks(Parser &P) override {
+      return new ConformingMethodListCallbacks(P, ExpectedTypeNames, Consumer);
+    }
+  };
+
+  return new ConformingMethodListCallbacksFactoryImpl(expectedTypeNames,
+                                                      Consumer);
+}
--- a/lib/IDE/ExprContextAnalysis.cpp
+++ b/lib/IDE/ExprContextAnalysis.cpp
@@ -30,6 +30,53 @@
 using namespace swift;
 using namespace ide;

+//===----------------------------------------------------------------------===//
+// prepareForRetypechecking(Expr *)
+//===----------------------------------------------------------------------===//
+
+/// Prepare the given expression for type-checking again, prinicipally by
+/// erasing any ErrorType types on the given expression, allowing later
+/// type-checking to make progress.
+///
+/// FIXME: this is fundamentally a workaround for the fact that we may end up
+/// typechecking parts of an expression more than once - first for checking
+/// the context, and later for checking more-specific things like unresolved
+/// members.  We should restructure code-completion type-checking so that we
+/// never typecheck more than once (or find a more principled way to do it).
+void swift::ide::prepareForRetypechecking(Expr *E) {
+  assert(E);
+  struct Eraser : public ASTWalker {
+    std::pair<bool, Expr *> walkToExprPre(Expr *expr) override {
+      if (expr && expr->getType() && (expr->getType()->hasError() ||
+                                      expr->getType()->hasUnresolvedType()))
+        expr->setType(Type());
+      if (auto *ACE = dyn_cast_or_null<AutoClosureExpr>(expr)) {
+        return { true, ACE->getSingleExpressionBody() };
+      }
+      return { true, expr };
+    }
+    bool walkToTypeLocPre(TypeLoc &TL) override {
+      if (TL.getType() && (TL.getType()->hasError() ||
+                           TL.getType()->hasUnresolvedType()))
+        TL.setType(Type());
+      return true;
+    }
+
+    std::pair<bool, Pattern*> walkToPatternPre(Pattern *P) override {
+      if (P && P->hasType() && (P->getType()->hasError() ||
+                                P->getType()->hasUnresolvedType())) {
+        P->setType(Type());
+      }
+      return { true, P };
+    }
+    std::pair<bool, Stmt *> walkToStmtPre(Stmt *S) override {
+      return { false, S };
+    }
+  };
+
+  E->walk(Eraser());
+}
+
 //===----------------------------------------------------------------------===//
 // typeCheckContextUntil(DeclContext, SourceLoc)
 //===----------------------------------------------------------------------===//
--- a/lib/IDE/ExprContextAnalysis.h
+++ b/lib/IDE/ExprContextAnalysis.h
@@ -25,6 +25,11 @@ class AnyFunctionType;

 namespace ide {

+/// Prepare the given expression for type-checking again, prinicipally by
+/// erasing any ErrorType types on the given expression, allowing later
+/// type-checking to make progress.
+void prepareForRetypechecking(Expr *E);
+
 /// Type check parent contexts of the given decl context, and the body of the
 /// given context until \c Loc if the context is a function body.
 void typeCheckContextUntil(DeclContext *DC, SourceLoc Loc);
--- a/lib/IDE/TypeContextInfo.cpp
+++ b/lib/IDE/TypeContextInfo.cpp
@@ -35,45 +35,10 @@ public:
  ContextInfoCallbacks(Parser &P, TypeContextInfoConsumer &Consumer)
      : CodeCompletionCallbacks(P), Consumer(Consumer) {}

-  void completeExpr() override{};
-
-  // Ignore callbacks for suffix completions
-  // {
-  void completeDotExpr(Expr *E, SourceLoc DotLoc) override {};
-  void completePostfixExpr(Expr *E, bool hasSpace) override {};
-  void completeExprSuper(SuperRefExpr *SRE) override {};
-  void completeExprSuperDot(SuperRefExpr *SRE) override {};
-  // }
-
-  // Ignore non-expression callbacks.
-  // {
-  void completeInPrecedenceGroup(SyntaxKind SK) override {};
-  void completePoundAvailablePlatform() override {};
-  void completeExprKeyPath(KeyPathExpr *KPE, SourceLoc DotLoc) override {}
-  void completeTypeSimpleBeginning() override {}
-  void completeTypeIdentifierWithDot(IdentTypeRepr *ITR) override {}
-  void completeTypeIdentifierWithoutDot(IdentTypeRepr *ITR) override {}
-  void completeDeclAttrKeyword(Decl *D, bool Sil, bool Param) override {}
-  void completeDeclAttrParam(DeclAttrKind DK, int Index) override {}
-  void completeNominalMemberBeginning(
-      SmallVectorImpl<StringRef> &Keywords) override {}
-  void completeImportDecl(
-      std::vector<std::pair<Identifier, SourceLoc>> &Path) override {}
-  void completeAfterPoundExpr(CodeCompletionExpr *E,
-                              Optional<StmtKind> ParentKind) override {}
-  void completeAfterPoundDirective() override {}
-  void completePlatformCondition() override {}
-  void completeGenericParams(TypeLoc TL) override {}
-  void completeAfterIfStmt(bool hasElse) override {}
-  void completeAccessorBeginning() override {};
-  // }
-
-  void completeStmtOrExpr() override {};
  void completePostfixExprBeginning(CodeCompletionExpr *E) override;
  void completeForEachSequenceBeginning(CodeCompletionExpr *E) override;
  void completeCaseStmtBeginning() override;

-  void completeAssignmentRHS(AssignExpr *E) override {};
  void completeCallArg(CodeCompletionExpr *E) override;
  void completeReturnStmt(CodeCompletionExpr *E) override;
  void completeYieldStmt(CodeCompletionExpr *E,
@@ -83,8 +48,6 @@ public:
                                SourceLoc DotLoc) override;
  void completeCaseStmtDotPrefix() override;

-  void completePostfixExprParen(Expr *E, Expr *CodeCompletionE) override{};
-
  void doneParsing() override;
 };

--- a/test/IDE/conforming-methods-basic.swift
+++ b/test/IDE/conforming-methods-basic.swift
@@ -0,0 +1,49 @@
+// RUN: %target-swift-ide-test -conforming-methods -source-filename %s -code-completion-token=TEST_1 -module-name MyModule -conforming-methods-expected-types '$s8MyModule7Target1PD' -conforming-methods-expected-types '$s8MyModule7Target2PD' | %FileCheck %s -check-prefix=CHECK_1
+// RUN: %target-swift-ide-test -conforming-methods -source-filename %s -code-completion-token=TEST_2 -module-name MyModule -conforming-methods-expected-types '$s8MyModule7Target1PD' -conforming-methods-expected-types '$s8MyModule7Target2PD' | %FileCheck %s -check-prefix=CHECK_1
+// RUN: %target-swift-ide-test -conforming-methods -source-filename %s -code-completion-token=TEST_3 -module-name MyModule -conforming-methods-expected-types '$s8MyModule7Target1PD' -conforming-methods-expected-types '$s8MyModule7Target2PD' | %FileCheck %s -check-prefix=CHECK_1
+// RUN: %target-swift-ide-test -conforming-methods -source-filename %s -code-completion-token=TEST_4 -module-name MyModule -conforming-methods-expected-types '$s8MyModule7Target1PD' -conforming-methods-expected-types '$s8MyModule7Target2PD' | %FileCheck %s -check-prefix=CHECK_1
+
+protocol Target1 {
+  associatedType Assoc
+}
+protocol Target2 {}
+protocol Target3 {}
+
+struct ConcreteTarget1 : Target1 {}
+struct ConcreteTarget2 : Target2 {}
+struct ConcreteTarget3 : Target3 {}
+
+
+struct C {
+  func returnsConcreteTarget1() -> ConcreteTarget1 { fatalError() }
+  func returnsExistentialTarget1() -> Target1 { fatalError() }
+}
+
+protocol P {
+  func returnsConcreteTarget2() -> ConcreteTarget2
+  func returnsConcreteTarget3() -> ConcreteTarget3
+}
+
+extension P {
+  func returnSelf() -> Self { return self }
+  func returnsConcreteTarget2() -> ConcreteTarget2 { fatalError() }
+  func returnsConcreteTarget3() -> ConcreteTarget3 { fatalError() }
+}
+
+extension C : P {}
+
+func testing(obj: C) {
+  let _ = obj #^TEST_1^#
+  let _ = obj .#^TEST_2^#
+  let _ = obj.returnSelf()#^TEST_3^#
+  let _ = obj.returnSelf().#^TEST_4^#
+}
+
+// CHECK_1:      -----BEGIN CONFORMING METHOD LIST-----
+// CHECK_1_NEXT: - TypeName: C
+// CHECK_1_NEXT: - Members:
+// CHECK_1_NEXT:    - Name: returnsConcreteTarget1()
+// CHECK_1_NEXT:      TypeName: ConcreteTarget1
+// CHECK_1_NEXT:    - Name: returnsConcreteTarget1()
+// CHECK_1_NEXT:      TypeName: ConcreteTarget1
+// CHECK_1_NEXT: -----END CONFORMING METHOD LIST-----
--- a/test/SourceKit/ConformingMethods/basic.swift
+++ b/test/SourceKit/ConformingMethods/basic.swift
@@ -0,0 +1,30 @@
+protocol Target1 {}
+protocol Target2 {}
+protocol Target3 {}
+
+struct ConcreteTarget1 : Target1 {}
+struct ConcreteTarget2 : Target2 {}
+struct ConcreteTarget3 : Target3 {}
+
+protocol P {
+  associatedtype Assoc
+  func protocolMethod(asc: Assoc) -> Self
+}
+extension P {
+  func protocolMethod(asc: Assoc) -> Self { return self }
+}
+
+class C : P {
+  typealias Assoc = String
+  static func staticMethod() -> Self {}
+  func instanceMethod(x: Int) -> C {}
+  func methodForTarget1() -> ConcreteTarget1 {}
+  func methodForTarget2() -> ConcreteTarget2 {}
+}
+
+func testing(obj: C) {
+  let _ = obj.
+}
+
+// RUN: %sourcekitd-test -req=conformingmethods -pos=26:14 %s -req-opts=expectedtypes='$s8MyModule7Target2PD;$s8MyModule7Target1PD' -- -module-name MyModule %s > %t.response
+// RUN: diff -u %s.response %t.response
--- a/test/SourceKit/ConformingMethods/basic.swift.response
+++ b/test/SourceKit/ConformingMethods/basic.swift.response
@@ -0,0 +1,20 @@
+{
+  key.typename: "C",
+  key.typeusr: "$s8MyModule1CCD",
+  key.members: [
+    {
+      key.name: "methodForTarget1()",
+      key.sourcetext: "methodForTarget1()",
+      key.description: "methodForTarget1()",
+      key.typename: "ConcreteTarget1",
+      key.typeusr: "$s8MyModule15ConcreteTarget1VD"
+    },
+    {
+      key.name: "methodForTarget2()",
+      key.sourcetext: "methodForTarget2()",
+      key.description: "methodForTarget2()",
+      key.typename: "ConcreteTarget2",
+      key.typeusr: "$s8MyModule15ConcreteTarget2VD"
+    }
+  ]
+}
--- a/tools/SourceKit/include/SourceKit/Core/LangSupport.h
+++ b/tools/SourceKit/include/SourceKit/Core/LangSupport.h
@@ -533,6 +533,31 @@ public:
  virtual void failed(StringRef ErrDescription) = 0;
 };

+struct ConformingMethodListResult {
+  StringRef TypeName;
+  StringRef TypeUSR;
+
+  struct Member {
+    StringRef Name;
+    StringRef TypeName;
+    StringRef TypeUSR;
+    StringRef Description;
+    StringRef SourceText;
+    StringRef DocBrief;
+  };
+  ArrayRef<Member> Members;
+};
+
+class ConformingMethodListConsumer {
+  virtual void anchor();
+
+public:
+  virtual ~ConformingMethodListConsumer() {}
+
+  virtual void handleResult(const ConformingMethodListResult &Result) = 0;
+  virtual void failed(StringRef ErrDescription) = 0;
+};
+
 class LangSupport {
  virtual void anchor();

@@ -693,6 +718,12 @@ public:
                                        ArrayRef<const char *> Args,
                                        TypeContextInfoConsumer &Consumer) = 0;

+  virtual void getConformingMethodList(llvm::MemoryBuffer *inputBuf,
+                                       unsigned Offset,
+                                       ArrayRef<const char *> Args,
+                                       ArrayRef<const char *> ExpectedTypes,
+                                       ConformingMethodListConsumer &Consumer) = 0;
+
  virtual void getStatistics(StatisticsReceiver) = 0;
 };

--- a/tools/SourceKit/lib/Core/LangSupport.cpp
+++ b/tools/SourceKit/lib/Core/LangSupport.cpp
@@ -20,4 +20,5 @@ void EditorConsumer::anchor() { }
 void OptionsDictionary::anchor() {}
 void DocInfoConsumer::anchor() { }
 void TypeContextInfoConsumer::anchor() { }
+void ConformingMethodListConsumer::anchor() { }
 void LangSupport::anchor() { }
--- a/tools/SourceKit/lib/SwiftLang/CMakeLists.txt
+++ b/tools/SourceKit/lib/SwiftLang/CMakeLists.txt
@@ -2,6 +2,7 @@ add_sourcekit_library(SourceKitSwiftLang
  CodeCompletionOrganizer.cpp
  SwiftASTManager.cpp
  SwiftCompletion.cpp
+  SwiftConformingMethodList.cpp
  SwiftDocSupport.cpp
  SwiftEditor.cpp
  SwiftEditorInterfaceGen.cpp
--- a/tools/SourceKit/lib/SwiftLang/SwiftConformingMethodList.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftConformingMethodList.cpp
@@ -0,0 +1,213 @@
+//===--- SwiftConformingMethodList.cpp ------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2019 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
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "SwiftASTManager.h"
+#include "SwiftEditorDiagConsumer.h"
+#include "SwiftLangSupport.h"
+#include "swift/Frontend/Frontend.h"
+#include "swift/Frontend/PrintingDiagnosticConsumer.h"
+#include "swift/IDE/ConformingMethodList.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Comment.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/Type.h"
+
+using namespace SourceKit;
+using namespace swift;
+using namespace ide;
+
+static bool swiftConformingMethodListImpl(
+    SwiftLangSupport &Lang, llvm::MemoryBuffer *UnresolvedInputFile,
+    unsigned Offset, ArrayRef<const char *> Args,
+    ArrayRef<const char *> ExpectedTypeNames,
+    ide::ConformingMethodListConsumer &Consumer, std::string &Error) {
+  auto bufferIdentifier =
+      Lang.resolvePathSymlinks(UnresolvedInputFile->getBufferIdentifier());
+
+  auto origOffset = Offset;
+  auto newBuffer = SwiftLangSupport::makeCodeCompletionMemoryBuffer(
+      UnresolvedInputFile, Offset, bufferIdentifier);
+
+  CompilerInstance CI;
+  PrintingDiagnosticConsumer PrintDiags;
+  CI.addDiagnosticConsumer(&PrintDiags);
+
+  EditorDiagConsumer TraceDiags;
+  trace::TracedOperation TracedOp(trace::OperationKind::CodeCompletion);
+  if (TracedOp.enabled()) {
+    CI.addDiagnosticConsumer(&TraceDiags);
+    trace::SwiftInvocation SwiftArgs;
+    trace::initTraceInfo(SwiftArgs, bufferIdentifier, Args);
+    TracedOp.setDiagnosticProvider(
+        [&TraceDiags](SmallVectorImpl<DiagnosticEntryInfo> &diags) {
+          TraceDiags.getAllDiagnostics(diags);
+        });
+    TracedOp.start(
+        SwiftArgs,
+        {std::make_pair("OriginalOffset", std::to_string(origOffset)),
+         std::make_pair("Offset", std::to_string(Offset))});
+  }
+
+  CompilerInvocation Invocation;
+  bool Failed = Lang.getASTManager()->initCompilerInvocation(
+      Invocation, Args, CI.getDiags(), bufferIdentifier, Error);
+  if (Failed)
+    return false;
+  if (!Invocation.getFrontendOptions().InputsAndOutputs.hasInputs()) {
+    Error = "no input filenames specified";
+    return false;
+  }
+
+  Invocation.setCodeCompletionPoint(newBuffer.get(), Offset);
+
+  // Create a factory for code completion callbacks that will feed the
+  // Consumer.
+  std::unique_ptr<CodeCompletionCallbacksFactory> callbacksFactory(
+      ide::makeConformingMethodListCallbacksFactory(ExpectedTypeNames,
+                                                    Consumer));
+
+  Invocation.setCodeCompletionFactory(callbacksFactory.get());
+
+  if (CI.setup(Invocation)) {
+    // FIXME: error?
+    return true;
+  }
+  CI.performSema();
+
+  return true;
+}
+
+void SwiftLangSupport::getConformingMethodList(
+    llvm::MemoryBuffer *UnresolvedInputFile, unsigned Offset,
+    ArrayRef<const char *> Args, ArrayRef<const char *> ExpectedTypeNames,
+    SourceKit::ConformingMethodListConsumer &SKConsumer) {
+
+  class Consumer : public ide::ConformingMethodListConsumer {
+    SourceKit::ConformingMethodListConsumer &SKConsumer;
+
+  public:
+    Consumer(SourceKit::ConformingMethodListConsumer &SKConsumer)
+        : SKConsumer(SKConsumer) {}
+
+    /// Convert an IDE result to a SK result and send it to \c SKConsumer .
+    void handleResult(const ide::ConformingMethodListResult &Result) {
+      SmallString<512> SS;
+      llvm::raw_svector_ostream OS(SS);
+
+      unsigned TypeNameBegin = SS.size();
+      Result.ExprType.print(OS);
+      unsigned TypeNameLength = SS.size() - TypeNameBegin;
+
+      unsigned TypeUSRBegin = SS.size();
+      SwiftLangSupport::printTypeUSR(Result.ExprType, OS);
+      unsigned TypeUSRLength = SS.size() - TypeUSRBegin;
+
+      struct MemberInfo {
+        size_t DeclNameBegin = 0;
+        size_t DeclNameLength = 0;
+        size_t TypeNameBegin = 0;
+        size_t TypeNameLength = 0;
+        size_t TypeUSRBegin = 0;
+        size_t TypeUSRLength = 0;
+        size_t DescriptionBegin = 0;
+        size_t DescriptionLength = 0;
+        size_t SourceTextBegin = 0;
+        size_t SourceTextLength = 0;
+        StringRef BriefComment;
+
+        MemberInfo() {}
+      };
+      SmallVector<MemberInfo, 8> Members;
+
+      for (auto member : Result.Members) {
+        Members.emplace_back();
+        auto &memberElem = Members.back();
+
+        auto funcTy = cast<FuncDecl>(member)->getMethodInterfaceType();
+        funcTy = Result.ExprType->getTypeOfMember(Result.DC->getParentModule(),
+                                                  member, funcTy);
+        auto resultTy = funcTy->castTo<FunctionType>()->getResult();
+
+        // Name.
+        memberElem.DeclNameBegin = SS.size();
+        member->getFullName().print(OS);
+        memberElem.DeclNameLength = SS.size() - memberElem.DeclNameBegin;
+
+        // Type name.
+        memberElem.TypeNameBegin = SS.size();
+        resultTy.print(OS);
+        memberElem.TypeNameLength = SS.size() - memberElem.TypeNameBegin;
+
+        // Type USR.
+        memberElem.TypeUSRBegin = SS.size();
+        SwiftLangSupport::printTypeUSR(resultTy, OS);
+        memberElem.TypeUSRLength = SS.size() - memberElem.TypeUSRBegin;
+
+        // Description.
+        memberElem.DescriptionBegin = SS.size();
+        SwiftLangSupport::printMemberDeclDescription(
+            member, Result.ExprType, /*usePlaceholder=*/false, OS);
+        memberElem.DescriptionLength =
+            SS.size() - memberElem.DescriptionBegin;
+
+        // Sourcetext.
+        memberElem.SourceTextBegin = SS.size();
+        SwiftLangSupport::printMemberDeclDescription(
+            member, Result.ExprType, /*usePlaceholder=*/true, OS);
+        memberElem.SourceTextLength =
+            SS.size() - memberElem.SourceTextBegin;
+
+        // DocBrief.
+        auto MaybeClangNode = member->getClangNode();
+        if (MaybeClangNode) {
+          if (auto *D = MaybeClangNode.getAsDecl()) {
+            const auto &ClangContext = D->getASTContext();
+            if (const clang::RawComment *RC =
+                    ClangContext.getRawCommentForAnyRedecl(D))
+              memberElem.BriefComment = RC->getBriefText(ClangContext);
+          }
+        } else {
+          memberElem.BriefComment = member->getBriefComment();
+        }
+      }
+
+      SourceKit::ConformingMethodListResult SKResult;
+      SmallVector<SourceKit::ConformingMethodListResult::Member, 8>
+          SKMembers;
+
+      for (auto info : Members) {
+        StringRef Name(SS.begin() + info.DeclNameBegin, info.DeclNameLength);
+        StringRef TypeName(SS.begin() + info.TypeNameBegin,
+                           info.TypeNameLength);
+        StringRef TypeUSR(SS.begin() + info.TypeUSRBegin, info.TypeUSRLength);
+        StringRef Description(SS.begin() + info.DescriptionBegin,
+                              info.DescriptionLength);
+        StringRef SourceText(SS.begin() + info.SourceTextBegin,
+                             info.SourceTextLength);
+        SKMembers.push_back({Name, TypeName, TypeUSR, Description, SourceText,
+                               info.BriefComment});
+      }
+
+      SKResult.TypeName = StringRef(SS.begin() + TypeNameBegin, TypeNameLength);
+      SKResult.TypeUSR = StringRef(SS.begin() + TypeUSRBegin, TypeUSRLength);
+      SKResult.Members = SKMembers;
+
+      SKConsumer.handleResult(SKResult);
+    }
+  } Consumer(SKConsumer);
+
+  std::string Error;
+  if (!swiftConformingMethodListImpl(*this, UnresolvedInputFile, Offset, Args,
+                                     ExpectedTypeNames, Consumer, Error)) {
+    SKConsumer.failed(Error);
+  }
+}
--- a/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp
@@ -18,6 +18,7 @@

 #include "swift/AST/ASTVisitor.h"
 #include "swift/AST/ClangModuleLoader.h"
+#include "swift/AST/ParameterList.h"
 #include "swift/AST/SILOptions.h"
 #include "swift/AST/USRGeneration.h"
 #include "swift/Config.h"
@@ -190,6 +191,26 @@ SwiftLangSupport::SwiftLangSupport(SourceKit::Context &SKCtx)
 SwiftLangSupport::~SwiftLangSupport() {
 }

+std::unique_ptr<llvm::MemoryBuffer>
+SwiftLangSupport::makeCodeCompletionMemoryBuffer(
+    const llvm::MemoryBuffer *origBuf, unsigned &Offset,
+    const std::string bufferIdentifier) {
+
+  auto origBuffSize = origBuf->getBufferSize();
+  if (Offset > origBuffSize)
+    Offset = origBuffSize;
+
+  auto newBuffer = llvm::WritableMemoryBuffer::getNewUninitMemBuffer(
+      origBuffSize + 1, bufferIdentifier);
+  auto *pos = origBuf->getBufferStart() + Offset;
+  auto *newPos =
+      std::copy(origBuf->getBufferStart(), pos, newBuffer->getBufferStart());
+  *newPos = '\0';
+  std::copy(pos, origBuf->getBufferEnd(), newPos + 1);
+
+  return std::unique_ptr<llvm::MemoryBuffer>(newBuffer.release());
+}
+
 UIdent SwiftLangSupport::getUIDForDecl(const Decl *D, bool IsRef) {
  return UIdentVisitor(IsRef).visit(const_cast<Decl*>(D));
 }
@@ -750,6 +771,71 @@ bool SwiftLangSupport::printAccessorUSR(const AbstractStorageDecl *D,
  return ide::printAccessorUSR(D, AccKind, OS);
 }

+void SwiftLangSupport::printMemberDeclDescription(const swift::ValueDecl *VD,
+                                                  swift::Type baseTy,
+                                                  bool usePlaceholder,
+                                                  llvm::raw_ostream &OS) {
+  // Base name.
+  OS << VD->getBaseName().userFacingName();
+
+  // Parameters.
+  auto *M = VD->getModuleContext();
+  auto substMap = baseTy->getMemberSubstitutionMap(M, VD);
+  auto printSingleParam = [&](ParamDecl *param) {
+    auto paramTy = param->getInterfaceType();
+
+    // Label.
+    if (!param->getArgumentName().empty())
+      OS << param->getArgumentName() << ": ";
+
+    // InOut.
+    if (param->isInOut()) {
+      OS << "&";
+      paramTy = paramTy->getInOutObjectType();
+    }
+
+    // Type.
+    if (usePlaceholder)
+      OS << "<#T##";
+
+    if (auto substitutedTy = paramTy.subst(substMap))
+      paramTy = substitutedTy;
+
+    if (paramTy->hasError() && param->getTypeLoc().hasLocation()) {
+      // Fallback to 'TypeRepr' printing.
+      param->getTypeLoc().getTypeRepr()->print(OS);
+    } else {
+      paramTy.print(OS);
+    }
+
+    if (usePlaceholder)
+      OS << "#>";
+  };
+  auto printParams = [&](const ParameterList *params) {
+    OS << '(';
+    bool isFirst = true;
+    for (auto param : params->getArray()) {
+      if (isFirst)
+        isFirst = false;
+      else
+        OS << ", ";
+      printSingleParam(param);
+    }
+    OS << ')';
+  };
+  if (auto EED = dyn_cast<EnumElementDecl>(VD)) {
+    if (auto params = EED->getParameterList())
+      printParams(params);
+  } else if (auto *FD = dyn_cast<FuncDecl>(VD)) {
+    if (auto params = FD->getParameters())
+      printParams(params);
+  } else if (isa<VarDecl>(VD)) {
+    // Var decl doesn't have parameters.
+  } else {
+    llvm_unreachable("Unsupported Decl kind for printMemberDeclDescription()");
+  }
+}
+
 std::string SwiftLangSupport::resolvePathSymlinks(StringRef FilePath) {
  std::string InputPath = FilePath;
 #if !defined(_WIN32)
--- a/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h
+++ b/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h
@@ -306,6 +306,13 @@ public:
    return CCCache;
  }

+  /// Copy a memory buffer inserting '0' at the position of \c origBuf.
+  // TODO: Share with code completion.
+  static std::unique_ptr<llvm::MemoryBuffer>
+  makeCodeCompletionMemoryBuffer(const llvm::MemoryBuffer *origBuf,
+                                 unsigned &Offset,
+                                 const std::string bufferIdentifier);
+
  static SourceKit::UIdent getUIDForDecl(const swift::Decl *D,
                                         bool IsRef = false);
  static SourceKit::UIdent getUIDForExtensionOfDecl(const swift::Decl *D);
@@ -381,6 +388,14 @@ public:
  static void
  printFullyAnnotatedGenericReq(const swift::GenericSignature *Sig,
                                llvm::raw_ostream &OS);
+
+  /// Print 'description' or 'sourcetext' the given \p VD to \p OS. If
+  /// \p usePlaceholder is \c true, call argument positions are substituted with
+  /// a typed editor placeholders which is suitable for 'sourcetext'.
+  static void
+  printMemberDeclDescription(const swift::ValueDecl *VD, swift::Type baseTy,
+                             bool usePlaceholder, llvm::raw_ostream &OS);
+
  /// Tries to resolve the path to the real file-system path. If it fails it
  /// returns the original path;
  static std::string resolvePathSymlinks(StringRef FilePath);
@@ -528,6 +543,11 @@ public:
                                ArrayRef<const char *> Args,
                                TypeContextInfoConsumer &Consumer) override;

+  void getConformingMethodList(llvm::MemoryBuffer *inputBuf, unsigned Offset,
+                               ArrayRef<const char *> Args,
+                               ArrayRef<const char *> ExpectedTypes,
+                               ConformingMethodListConsumer &Consumer) override;
+
  void getStatistics(StatisticsReceiver) override;

 private:
--- a/tools/SourceKit/lib/SwiftLang/SwiftTypeContextInfo.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftTypeContextInfo.cpp
@@ -24,28 +24,6 @@ using namespace SourceKit;
 using namespace swift;
 using namespace ide;

-/// Copy a memory buffer inserting '0' at the position of \c origBuf.
-// TODO: Share with code completion.
-static std::unique_ptr<llvm::MemoryBuffer>
-makeCodeCompletionMemoryBuffer(const llvm::MemoryBuffer *origBuf,
-                               unsigned &Offset,
-                               const std::string bufferIdentifier) {
-
-  auto origBuffSize = origBuf->getBufferSize();
-  if (Offset > origBuffSize)
-    Offset = origBuffSize;
-
-  auto newBuffer = llvm::WritableMemoryBuffer::getNewUninitMemBuffer(
-      origBuffSize + 1, bufferIdentifier);
-  auto *pos = origBuf->getBufferStart() + Offset;
-  auto *newPos =
-      std::copy(origBuf->getBufferStart(), pos, newBuffer->getBufferStart());
-  *newPos = '\0';
-  std::copy(pos, origBuf->getBufferEnd(), newPos + 1);
-
-  return std::unique_ptr<llvm::MemoryBuffer>(newBuffer.release());
-}
-
 static bool swiftTypeContextInfoImpl(SwiftLangSupport &Lang,
                                     llvm::MemoryBuffer *UnresolvedInputFile,
                                     unsigned Offset,
@@ -56,8 +34,8 @@ static bool swiftTypeContextInfoImpl(SwiftLangSupport &Lang,
      Lang.resolvePathSymlinks(UnresolvedInputFile->getBufferIdentifier());

  auto origOffset = Offset;
-  auto newBuffer = makeCodeCompletionMemoryBuffer(UnresolvedInputFile, Offset,
-                                                  bufferIdentifier);
+  auto newBuffer = SwiftLangSupport::makeCodeCompletionMemoryBuffer(
+      UnresolvedInputFile, Offset, bufferIdentifier);

  CompilerInstance CI;
  PrintingDiagnosticConsumer PrintDiags;
@@ -107,12 +85,6 @@ static bool swiftTypeContextInfoImpl(SwiftLangSupport &Lang,
  return true;
 }

-/// Print 'description' or 'sourcetext' the given \c VD to \c OS. If
-/// \c usePlaceholder is true, call argument positions are substituted with
-/// type editor placeholders which is suitable for 'sourcetext'.
-static void printDeclDescription(llvm::raw_ostream &OS, Type baseTy,
-                                 ValueDecl *VD, bool usePlaceholder);
-
 void SwiftLangSupport::getExpressionContextInfo(
    llvm::MemoryBuffer *UnresolvedInputFile, unsigned Offset,
    ArrayRef<const char *> Args,
@@ -144,15 +116,15 @@ void SwiftLangSupport::getExpressionContextInfo(

        // Description.
        unsigned DescriptionBegin = SS.size();
-        printDeclDescription(OS, Item.ExpectedTy, member,
-                             /*usePlaceholder=*/false);
+        SwiftLangSupport::printMemberDeclDescription(
+            member, Item.ExpectedTy, /*usePlaceholder=*/false, OS);
        unsigned DescriptionLength = SS.size() - DescriptionBegin;
        StringRef Description(SS.begin() + DescriptionBegin, DescriptionLength);

        // Sourcetext.
        unsigned SourceTextBegin = SS.size();
-        printDeclDescription(OS, Item.ExpectedTy, member,
-                             /*usePlaceholder=*/true);
+        SwiftLangSupport::printMemberDeclDescription(
+            member, Item.ExpectedTy, /*usePlaceholder=*/true, OS);
        unsigned SourceTextLength = SS.size() - SourceTextBegin;
        StringRef SourceText(SS.begin() + SourceTextBegin, SourceTextLength);

@@ -198,67 +170,3 @@ void SwiftLangSupport::getExpressionContextInfo(
    SKConsumer.failed(Error);
  }
 }
-
-static void printDeclDescription(llvm::raw_ostream &OS, Type baseTy,
-                                 ValueDecl *VD, bool usePlaceholder) {
-
-  // Base name.
-  OS << VD->getBaseName().userFacingName();
-
-  // Parameters.
-  auto *M = VD->getModuleContext();
-  auto substMap = baseTy->getMemberSubstitutionMap(M, VD);
-  auto printSingleParam = [&](ParamDecl *param) {
-    auto paramTy = param->getInterfaceType();
-
-    // Label.
-    if (!param->getArgumentName().empty())
-      OS << param->getArgumentName() << ": ";
-
-    // InOut.
-    if (param->isInOut()) {
-      OS << "&";
-      paramTy = paramTy->getInOutObjectType();
-    }
-
-    // Type.
-    if (usePlaceholder)
-      OS << "<#T##";
-
-    if (auto substitutedTy = paramTy.subst(substMap))
-      paramTy = substitutedTy;
-
-    if (paramTy->hasError() && param->getTypeLoc().hasLocation()) {
-      // Fallback to 'TypeRepr' printing.
-      param->getTypeLoc().getTypeRepr()->print(OS);
-    } else {
-      paramTy.print(OS);
-    }
-
-    if (usePlaceholder)
-      OS << "#>";
-  };
-  auto printParams = [&](ParameterList *params) {
-    OS << '(';
-    bool isFirst = true;
-    for (auto param : params->getArray()) {
-      if (isFirst)
-        isFirst = false;
-      else
-        OS << ", ";
-      printSingleParam(param);
-    }
-    OS << ')';
-  };
-  if (auto EED = dyn_cast<EnumElementDecl>(VD)) {
-    if (auto params = EED->getParameterList())
-      printParams(params);
-  } else if (auto *FD = dyn_cast<FuncDecl>(VD)) {
-    if (auto params = FD->getParameters())
-      printParams(params);
-  } else if (isa<VarDecl>(VD)) {
-    // Var decl doesn't have parameters.
-  } else {
-    llvm_unreachable("Invalid Decl type for context info implicit member");
-  }
-}
--- a/tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp
+++ b/tools/SourceKit/tools/sourcekitd-test/TestOptions.cpp
@@ -116,6 +116,7 @@ bool TestOptions::parseArgs(llvm::ArrayRef<const char *> Args) {
        .Case("complete.cache.ondisk", SourceKitRequest::CodeCompleteCacheOnDisk)
        .Case("complete.setpopularapi", SourceKitRequest::CodeCompleteSetPopularAPI)
        .Case("typecontextinfo", SourceKitRequest::TypeContextInfo)
+        .Case("conformingmethods", SourceKitRequest::ConformingMethodList)
        .Case("cursor", SourceKitRequest::CursorInfo)
        .Case("related-idents", SourceKitRequest::RelatedIdents)
        .Case("syntax-map", SourceKitRequest::SyntaxMap)
--- a/tools/SourceKit/tools/sourcekitd-test/TestOptions.h
+++ b/tools/SourceKit/tools/sourcekitd-test/TestOptions.h
@@ -33,6 +33,7 @@ enum class SourceKitRequest {
  CodeCompleteCacheOnDisk,
  CodeCompleteSetPopularAPI,
  TypeContextInfo,
+  ConformingMethodList,
  CursorInfo,
  RangeInfo,
  RelatedIdents,
--- a/tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp
+++ b/tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp
@@ -564,6 +564,30 @@ static int handleTestInvocation(TestOptions Opts, TestOptions &InitOpts) {
    sourcekitd_request_dictionary_set_int64(Req, KeyOffset, ByteOffset);
    break;

+  case SourceKitRequest::ConformingMethodList:
+    sourcekitd_request_dictionary_set_uid(Req, KeyRequest,
+                                          RequestConformingMethodList);
+    sourcekitd_request_dictionary_set_int64(Req, KeyOffset, ByteOffset);
+    for (auto &Opt : Opts.RequestOptions) {
+      auto KeyValue = StringRef(Opt).split('=');
+      if (KeyValue.first == "expectedtypes") {
+        SmallVector<StringRef, 4> expectedTypeNames;
+        KeyValue.second.split(expectedTypeNames, ';');
+
+        auto typenames = sourcekitd_request_array_create(nullptr, 0);
+        for (auto &name : expectedTypeNames) {
+          std::string n = name;
+          sourcekitd_request_array_set_string(typenames, SOURCEKITD_ARRAY_APPEND, n.c_str());
+        }
+
+        sourcekitd_request_dictionary_set_value(Req, KeyExpectedTypes, typenames);
+      } else {
+        llvm::errs() << "invalid key '" << KeyValue.first << "' in -req-opts\n";
+        return 1;
+      }
+    }
+    break;
+
  case SourceKitRequest::CursorInfo:
    sourcekitd_request_dictionary_set_uid(Req, KeyRequest, RequestCursorInfo);
    if (Opts.CollectActionables) {
@@ -1013,6 +1037,7 @@ static bool handleResponse(sourcekitd_response_t Resp, const TestOptions &Opts,
    case SourceKitRequest::CodeCompleteCacheOnDisk:
    case SourceKitRequest::CodeCompleteSetPopularAPI:
    case SourceKitRequest::TypeContextInfo:
+    case SourceKitRequest::ConformingMethodList:
      sourcekitd_response_description_dump_filedesc(Resp, STDOUT_FILENO);
      break;

--- a/tools/SourceKit/tools/sourcekitd/lib/API/Requests.cpp
+++ b/tools/SourceKit/tools/sourcekitd/lib/API/Requests.cpp
@@ -171,6 +171,11 @@ static sourcekitd_response_t typeContextInfo(llvm::MemoryBuffer *InputBuf,
                                             int64_t Offset,
                                             ArrayRef<const char *> Args);

+static sourcekitd_response_t
+conformingMethodList(llvm::MemoryBuffer *InputBuf, int64_t Offset,
+                     ArrayRef<const char *> Args,
+                     ArrayRef<const char *> ExpectedTypes);
+
 static sourcekitd_response_t
 editorOpen(StringRef Name, llvm::MemoryBuffer *Buf,
           SKEditorConsumerOptions Opts, ArrayRef<const char *> Args);
@@ -886,6 +891,21 @@ handleSemanticRequest(RequestDict Req,
    return Rec(typeContextInfo(InputBuf.get(), Offset, Args));
  }

+  if (ReqUID == RequestConformingMethodList) {
+    std::unique_ptr<llvm::MemoryBuffer> InputBuf =
+        getInputBufForRequest(SourceFile, SourceText, ErrBuf);
+    if (!InputBuf)
+      return Rec(createErrorRequestFailed(ErrBuf.c_str()));
+    int64_t Offset;
+    if (Req.getInt64(KeyOffset, Offset, /*isOptional=*/false))
+      return Rec(createErrorRequestInvalid("missing 'key.offset'"));
+    SmallVector<const char *, 8> ExpectedTypeNames;
+    if (Req.getStringArray(KeyExpectedTypes, ExpectedTypeNames, true))
+      return Rec(createErrorRequestInvalid("invalid 'key.expectedtypes'"));
+    return Rec(
+        conformingMethodList(InputBuf.get(), Offset, Args, ExpectedTypeNames));
+  }
+
  if (!SourceFile.hasValue())
    return Rec(createErrorRequestInvalid("missing 'key.sourcefile'"));

@@ -2110,6 +2130,57 @@ static sourcekitd_response_t typeContextInfo(llvm::MemoryBuffer *InputBuf,
  return RespBuilder.createResponse();
 }

+//===----------------------------------------------------------------------===//
+// Conforming Method List
+//===----------------------------------------------------------------------===//
+
+static sourcekitd_response_t
+conformingMethodList(llvm::MemoryBuffer *InputBuf, int64_t Offset,
+                     ArrayRef<const char *> Args,
+                     ArrayRef<const char *> ExpectedTypes) {
+  ResponseBuilder RespBuilder;
+
+  class Consumer : public ConformingMethodListConsumer {
+    ResponseBuilder::Dictionary SKResult;
+    Optional<std::string> ErrorDescription;
+
+  public:
+    Consumer(ResponseBuilder Builder) : SKResult(Builder.getDictionary()) {}
+
+    void handleResult(const ConformingMethodListResult &Result) override {
+      SKResult.set(KeyTypeName, Result.TypeName);
+      SKResult.set(KeyTypeUsr, Result.TypeUSR);
+      auto members = SKResult.setArray(KeyMembers);
+      for (auto member : Result.Members) {
+        auto memberElem = members.appendDictionary();
+        memberElem.set(KeyName, member.Name);
+        memberElem.set(KeyTypeName, member.TypeName);
+        memberElem.set(KeyTypeUsr, member.TypeUSR);
+        memberElem.set(KeyDescription, member.Description);
+        memberElem.set(KeySourceText, member.SourceText);
+        if (!member.DocBrief.empty())
+          memberElem.set(KeyDocBrief, member.DocBrief);
+      }
+    }
+
+    void failed(StringRef ErrDescription) override {
+      ErrorDescription = ErrDescription;
+    }
+
+    bool isError() const { return ErrorDescription.hasValue(); }
+    const char *getErrorDescription() const {
+      return ErrorDescription->c_str();
+    }
+  } Consumer(RespBuilder);
+
+  LangSupport &Lang = getGlobalContext().getSwiftLangSupport();
+  Lang.getConformingMethodList(InputBuf, Offset, Args, ExpectedTypes, Consumer);
+
+  if (Consumer.isError())
+    return createErrorRequestFailed(Consumer.getErrorDescription());
+  return RespBuilder.createResponse();
+}
+
 //===----------------------------------------------------------------------===//
 // Editor
 //===----------------------------------------------------------------------===//
--- a/tools/swift-ide-test/swift-ide-test.cpp
+++ b/tools/swift-ide-test/swift-ide-test.cpp
@@ -33,6 +33,7 @@
 #include "swift/Frontend/PrintingDiagnosticConsumer.h"
 #include "swift/IDE/CodeCompletion.h"
 #include "swift/IDE/CommentConversion.h"
+#include "swift/IDE/ConformingMethodList.h"
 #include "swift/IDE/ModuleInterfacePrinting.h"
 #include "swift/IDE/REPLCodeCompletion.h"
 #include "swift/IDE/SourceEntityWalker.h"
@@ -101,6 +102,7 @@ enum class ActionType {
  ReconstructType,
  Range,
  TypeContextInfo,
+  ConformingMethodList,
 };

 class NullDebuggerClient : public DebuggerClient {
@@ -225,7 +227,10 @@ Action(llvm::cl::desc("Mode:"), llvm::cl::init(ActionType::None),
                      "Print indexed symbol information"),
           clEnumValN(ActionType::TypeContextInfo,
 	                    "type-context-info",
-                      "Perform expression context info analysis")));
+                      "Perform expression context info analysis"),
+           clEnumValN(ActionType::ConformingMethodList,
+	                    "conforming-methods",
+                      "Perform conforming method analysis for expression")));

 static llvm::cl::opt<std::string>
 SourceFilename("source-filename", llvm::cl::desc("Name of the source file"),
@@ -419,6 +424,13 @@ DebugClientDiscriminator("debug-client-discriminator",
  llvm::cl::desc("A discriminator to prefer in lookups"),
  llvm::cl::cat(Category));

+// '-conforming-methods' options.
+
+static llvm::cl::list<std::string>
+ConformingMethodListExpectedTypes("conforming-methods-expected-types",
+    llvm::cl::desc("Set expected types for comforming method list"),
+    llvm::cl::cat(Category));
+
 // '-syntax-coloring' options.

 static llvm::cl::opt<bool>
@@ -748,6 +760,70 @@ static int doTypeContextInfo(const CompilerInvocation &InitInvok,
  return 0;
 }

+static int
+doConformingMethodList(const CompilerInvocation &InitInvok,
+                       StringRef SourceFilename, StringRef SecondSourceFileName,
+                       StringRef CodeCompletionToken,
+                       bool CodeCompletionDiagnostics,
+                       const std::vector<std::string> expectedTypeNames) {
+  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> FileBufOrErr =
+      llvm::MemoryBuffer::getFile(SourceFilename);
+  if (!FileBufOrErr) {
+    llvm::errs() << "error opening input file: "
+                 << FileBufOrErr.getError().message() << '\n';
+    return 1;
+  }
+
+  unsigned Offset;
+
+  std::unique_ptr<llvm::MemoryBuffer> CleanFile(removeCodeCompletionTokens(
+      FileBufOrErr.get().get(), CodeCompletionToken, &Offset));
+
+  if (Offset == ~0U) {
+    llvm::errs() << "could not find code completion token \""
+                 << CodeCompletionToken << "\"\n";
+    return 1;
+  }
+  llvm::outs() << "found code completion token " << CodeCompletionToken
+               << " at offset " << Offset << "\n";
+  llvm::errs() << "found code completion token " << CodeCompletionToken
+               << " at offset " << Offset << "\n";
+
+  CompilerInvocation Invocation(InitInvok);
+
+  Invocation.setCodeCompletionPoint(CleanFile.get(), Offset);
+
+  SmallVector<const char *, 4> typeNames;
+  for (auto &name : expectedTypeNames)
+    typeNames.push_back(name.c_str());
+
+  // Create a CodeCompletionConsumer.
+  std::unique_ptr<ide::ConformingMethodListConsumer> Consumer(
+      new ide::PrintingConformingMethodListConsumer(llvm::outs()));
+
+  // Create a factory for code completion callbacks that will feed the
+  // Consumer.
+  std::unique_ptr<CodeCompletionCallbacksFactory> callbacksFactory(
+      ide::makeConformingMethodListCallbacksFactory(typeNames, *Consumer));
+
+  Invocation.setCodeCompletionFactory(callbacksFactory.get());
+  if (!SecondSourceFileName.empty()) {
+    Invocation.getFrontendOptions().InputsAndOutputs.addInputFile(
+        SecondSourceFileName);
+  }
+  CompilerInstance CI;
+
+  PrintingDiagnosticConsumer PrintDiags;
+  if (CodeCompletionDiagnostics) {
+    // Display diagnostics to stderr.
+    CI.addDiagnosticConsumer(&PrintDiags);
+  }
+  if (CI.setup(Invocation))
+    return 1;
+  CI.performSema();
+  return 0;
+}
+
 static int doCodeCompletion(const CompilerInvocation &InitInvok,
                            StringRef SourceFilename,
                            StringRef SecondSourceFileName,
@@ -3277,6 +3353,19 @@ int main(int argc, char *argv[]) {
                                  options::CodeCompletionDiagnostics);
    break;

+  case ActionType::ConformingMethodList:
+    if (options::CodeCompletionToken.empty()) {
+      llvm::errs() << "token name required\n";
+      return 1;
+    }
+    ExitCode = doConformingMethodList(InitInvok,
+                                      options::SourceFilename,
+                                      options::SecondSourceFilename,
+                                      options::CodeCompletionToken,
+                                      options::CodeCompletionDiagnostics,
+                                      options::ConformingMethodListExpectedTypes);
+    break;
+
  case ActionType::SyntaxColoring:
    ExitCode = doSyntaxColoring(InitInvok,
                                options::SourceFilename,
--- a/utils/gyb_sourcekit_support/UIDs.py
+++ b/utils/gyb_sourcekit_support/UIDs.py
@@ -161,6 +161,8 @@ UID_KEYS = [
    KEY('CompileID', 'key.compileid'),
    KEY('CompilerArgsString', 'key.compilerargs-string'),
    KEY('ImplicitMembers', 'key.implicitmembers'),
+    KEY('ExpectedTypes', 'key.expectedtypes'),
+    KEY('Members', 'key.members'),
 ]


@@ -182,6 +184,7 @@ UID_REQUESTS = [
            'source.request.codecomplete.setpopularapi'),
    REQUEST('CodeCompleteSetCustom', 'source.request.codecomplete.setcustom'),
    REQUEST('TypeContextInfo', 'source.request.typecontextinfo'),
+    REQUEST('ConformingMethodList', 'source.request.conformingmethods'),
    REQUEST('CursorInfo', 'source.request.cursorinfo'),
    REQUEST('RangeInfo', 'source.request.rangeinfo'),
    REQUEST('RelatedIdents', 'source.request.relatedidents'),