diff --git include/clang/AST/ExprCXX.h include/clang/AST/ExprCXX.h
index 1911704..821f312 100644
--- include/clang/AST/ExprCXX.h
+++ include/clang/AST/ExprCXX.h
@@ -3123,7 +3123,113 @@ public:
   // Iterators
   child_range children() { return child_range(&Temporary, &Temporary + 1); }
 };
-  
+
+/// LambdaExpr - Represents a C++0x lambda expression, e.g.,
+/// @c [&sum] (int x) -> void { sum += x; }
+/// Holds related declarations, including the captures and closure type.
+class LambdaExpr : public Expr {
+public:
+  class Capture {
+    enum Kind {
+      CaptureThis,
+      CaptureByCopy,
+      CaptureByRef
+    };
+
+    llvm::PointerIntPair<Expr*, 2, Kind> InitAndKind;
+
+  public:
+    Capture(CXXThisExpr *Init)
+      : InitAndKind(Init, CaptureThis) {}
+
+    Capture(DeclRefExpr *Init, bool ByRef)
+      : InitAndKind(Init, ByRef ? CaptureByRef : CaptureByCopy) {}
+
+    bool isThisCapture() const { return InitAndKind.getInt() == CaptureThis; }
+    bool isCopyCapture() const { return InitAndKind.getInt() == CaptureByCopy; }
+    bool isReferenceCapture() const {
+      return InitAndKind.getInt() == CaptureByRef;
+    }
+
+    /// The initializing Expr for the captured entity. Will be either
+    /// CXXThisExpr or DeclRefExpr.
+    Expr *getInit() const { return InitAndKind.getPointer(); }
+
+    /// Convenience function for variable captures.
+    VarDecl *getVar() const {
+      DeclRefExpr *VarRef = cast<DeclRefExpr>(getInit());
+      return cast<VarDecl>(VarRef->getDecl());
+    }
+
+    SourceLocation getLoc() const { return getInit()->getExprLoc(); }
+
+  };
+
+private:
+  /// Array of explicit captures in source order.
+  Capture *Explicits;
+  unsigned NumExplicits;
+
+  /// Declaration for the closure type.
+  CXXRecordDecl *ClosureType;
+
+  /// Declaration for the function call operator of the closure type.
+  /// We cache it here to avoid lookup.
+  CXXMethodDecl *Function;
+
+  /// The temporary object resulting from evaluating the lambda expression,
+  /// represented by a call to the constructor of the closure type.
+  CXXConstructExpr *ClosureObject;
+
+protected:
+  LambdaExpr(CXXRecordDecl *ClosureType, QualType T,
+             Capture *Explicits, unsigned NumExplicits)
+    : Expr(LambdaExprClass, T, VK_RValue, OK_Ordinary,
+           // FIXME: Support templates and parameter packs later.
+           /*TypeDependent=*/false,
+           /*ValueDependent=*/false,
+           /*InstantiationDependent=*/false,
+           /*ContainsUnexpandedParameterPack=*/false),
+      Explicits(Explicits), NumExplicits(NumExplicits),
+      ClosureType(ClosureType) {}
+
+  explicit LambdaExpr(EmptyShell Empty) : Expr(LambdaExprClass, Empty) {}
+
+public:
+  static LambdaExpr *Create(ASTContext &C, CXXRecordDecl *ClosureType,
+                            const Capture *E, unsigned N);
+
+  unsigned getNumExplicits() const { return NumExplicits; }
+
+  typedef const Capture *capture_iterator;
+  typedef const Capture *capture_const_iterator;
+
+  capture_iterator explicits_begin() { return Explicits; }
+  capture_iterator explicits_end() { return Explicits + NumExplicits; }
+  capture_const_iterator explicits_begin() const { return Explicits; }
+  capture_const_iterator explicits_end() const {
+    return Explicits + NumExplicits;
+  }
+
+  CXXRecordDecl *getClosureType() const { return ClosureType; }
+
+  CXXMethodDecl *getFunction() const { return Function; }
+  void setFunction(CXXMethodDecl *D) { Function = D; }
+
+  CXXConstructExpr *getClosureObject() const { return ClosureObject; }
+  void setClosureObject(CXXConstructExpr *E) { ClosureObject = E; }
+
+  SourceRange getSourceRange() const;
+
+  static bool classof(const Stmt *T) {
+    return T->getStmtClass() == LambdaExprClass;
+  }
+  static bool classof(const LambdaExpr *) { return true; }
+
+  // Required to pass implementation check.
+  child_range children() { return child_range(); }
+};
+
 }  // end namespace clang
 
 #endif
diff --git include/clang/AST/RecursiveASTVisitor.h include/clang/AST/RecursiveASTVisitor.h
index 473ba66..55375ec 100644
--- include/clang/AST/RecursiveASTVisitor.h
+++ include/clang/AST/RecursiveASTVisitor.h
@@ -1901,6 +1901,12 @@ DEF_TRAVERSE_STMT(CXXConstructExpr, { })
 DEF_TRAVERSE_STMT(CallExpr, { })
 DEF_TRAVERSE_STMT(CXXMemberCallExpr, { })
 
+// FIXME: Implement.
+// Traverse captures, parameters, return type, body, etc.
+DEF_TRAVERSE_STMT(LambdaExpr, {
+  llvm_unreachable("unimplemented");
+})
+
 // These exprs (most of them), do not need any action except iterating
 // over the children.
 DEF_TRAVERSE_STMT(AddrLabelExpr, { })
diff --git include/clang/Basic/DiagnosticSemaKinds.td include/clang/Basic/DiagnosticSemaKinds.td
index a90849c..9c848c8 100644
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -1182,6 +1182,20 @@ def err_constexpr_tag : Error<
 def err_constexpr_dtor : Error<"destructor cannot be marked constexpr">;
 def err_constexpr_no_declarators : Error<
   "constexpr can only be used in variable and function declarations">;
+
+// C++0x lambda expressions
+def err_capture_more_than_once : Error<
+  "%0 can appear only once in a capture list">;
+def err_reference_capture_with_reference_default : Error<
+  "'&' cannot precede a capture when the capture default is '&'">;
+def err_this_capture_with_copy_default : Error<
+  "'this' cannot appear in a capture list when the capture default is '='">;
+def err_copy_capture_with_copy_default : Error<
+  "'&' must precede a capture when the capture default is '='">;
+def err_capture_does_not_name_variable : Error<
+  "%0 in capture list does not name a variable">;
+def err_capture_non_automatic_variable : Error<
+  "%0 cannot be captured because it does not have automatic storage duration">;
   
 // Objective-C++
 def err_objc_decls_may_only_appear_in_global_scope : Error<
diff --git include/clang/Basic/StmtNodes.td include/clang/Basic/StmtNodes.td
index 73996e4..a67dfa2 100644
--- include/clang/Basic/StmtNodes.td
+++ include/clang/Basic/StmtNodes.td
@@ -123,6 +123,7 @@ def SizeOfPackExpr : DStmt<Expr>;
 def SubstNonTypeTemplateParmExpr : DStmt<Expr>;
 def SubstNonTypeTemplateParmPackExpr : DStmt<Expr>;
 def MaterializeTemporaryExpr : DStmt<Expr>;
+def LambdaExpr : DStmt<Expr>;
 
 // Obj-C Expressions.
 def ObjCStringLiteral : DStmt<Expr>;
diff --git include/clang/Sema/Sema.h include/clang/Sema/Sema.h
index 423f29f..abeb3c6 100644
--- include/clang/Sema/Sema.h
+++ include/clang/Sema/Sema.h
@@ -98,6 +98,7 @@ namespace clang {
   class InitializedEntity;
   class IntegerLiteral;
   class LabelStmt;
+  class LambdaExpr;
   class LangOptions;
   class LocalInstantiationScope;
   class LookupResult;
@@ -4999,6 +5000,14 @@ public:
   DeclContext *FindInstantiatedContext(SourceLocation Loc, DeclContext *DC,
                           const MultiLevelTemplateArgumentList &TemplateArgs);
 
+  //===--------------------------------------------------------------------===//
+  // C++ Lambda Expressions (C++0x [expr.prim.lambda])
+
+  ExprResult ActOnLambdaIntroducer(Scope *S, const LambdaIntroducer &Intro);
+  void ActOnLambdaDeclarator(Scope *S, LambdaExpr *Lambda, Declarator &D);
+  void ActOnLambdaBody(Scope *S, LambdaExpr *Lambda, Stmt *Body);
+
+  //===--------------------------------------------------------------------===//
   // Objective-C declarations.
   Decl *ActOnStartClassInterface(SourceLocation AtInterfaceLoc,
                                  IdentifierInfo *ClassName,
diff --git include/clang/Serialization/ASTBitCodes.h include/clang/Serialization/ASTBitCodes.h
index 4c8eb28..3b5ec1f 100644
--- include/clang/Serialization/ASTBitCodes.h
+++ include/clang/Serialization/ASTBitCodes.h
@@ -1060,6 +1060,9 @@ namespace clang {
       EXPR_SUBST_NON_TYPE_TEMPLATE_PARM_PACK,// SubstNonTypeTemplateParmPackExpr
       EXPR_MATERIALIZE_TEMPORARY, // MaterializeTemporaryExpr
       
+      /// \brief LambdaExpr
+      EXPR_LAMBDA,
+
       // CUDA
       EXPR_CUDA_KERNEL_CALL,       // CUDAKernelCallExpr      
 
diff --git lib/AST/ExprCXX.cpp lib/AST/ExprCXX.cpp
index f92afff..35f2516 100644
--- lib/AST/ExprCXX.cpp
+++ lib/AST/ExprCXX.cpp
@@ -1012,4 +1012,18 @@ TemplateArgument SubstNonTypeTemplateParmPackExpr::getArgumentPack() const {
   return TemplateArgument(Arguments, NumArguments);
 }
 
+LambdaExpr *LambdaExpr::Create(ASTContext &C, CXXRecordDecl *ClosureType,
+                               const Capture *E, unsigned N) {
+  // Avoid new Capture[] because we don't want to provide a default constructor.
+  size_t Size = N * sizeof(Capture);
+  void *buffer = C.Allocate(Size, llvm::AlignOf<Capture>::Alignment);
+  memcpy(buffer, E, Size);
+
+  return new (C) LambdaExpr(ClosureType, C.getRecordType(ClosureType),
+                            static_cast<Capture*>(buffer), N);
+}
+
+SourceRange LambdaExpr::getSourceRange() const {
+  return ClosureType ? ClosureType->getSourceRange() : SourceRange();
+}
 
diff --git lib/AST/StmtPrinter.cpp lib/AST/StmtPrinter.cpp
index 79f14bc..24db42f 100644
--- lib/AST/StmtPrinter.cpp
+++ lib/AST/StmtPrinter.cpp
@@ -1503,6 +1503,11 @@ StmtPrinter::VisitObjCBridgedCastExpr(ObjCBridgedCastExpr *E) {
   PrintExpr(E->getSubExpr());
 }
 
+// FIXME: Implement.
+void StmtPrinter::VisitLambdaExpr(LambdaExpr *Node) {
+  llvm_unreachable("unimplemented");
+}
+
 void StmtPrinter::VisitBlockExpr(BlockExpr *Node) {
   BlockDecl *BD = Node->getBlockDecl();
   OS << "^";
diff --git lib/AST/StmtProfile.cpp lib/AST/StmtProfile.cpp
index 12321ef..6580e9b 100644
--- lib/AST/StmtProfile.cpp
+++ lib/AST/StmtProfile.cpp
@@ -449,6 +449,11 @@ void StmtProfiler::VisitBlockExpr(const BlockExpr *S) {
   VisitDecl(S->getBlockDecl());
 }
 
+// FIXME: Implement.
+void StmtProfiler::VisitLambdaExpr(const LambdaExpr *S) {
+  llvm_unreachable("unimplemented");
+}
+
 void StmtProfiler::VisitBlockDeclRefExpr(const BlockDeclRefExpr *S) {
   VisitExpr(S);
   VisitDecl(S->getDecl());
diff --git lib/Parse/ParseExprCXX.cpp lib/Parse/ParseExprCXX.cpp
index 1faeebc..d05c038 100644
--- lib/Parse/ParseExprCXX.cpp
+++ lib/Parse/ParseExprCXX.cpp
@@ -584,7 +584,7 @@ ExprResult Parser::TryParseLambdaExpression() {
   return ParseLambdaExpressionAfterIntroducer(Intro);
 }
 
-/// ParseLambdaExpression - Parse a lambda introducer.
+/// ParseLambdaIntroducer - Parse a lambda introducer.
 ///
 /// Returns a DiagnosticID if it hit something unexpected.
 llvm::Optional<unsigned> Parser::ParseLambdaIntroducer(LambdaIntroducer &Intro) {
@@ -652,7 +652,7 @@ llvm::Optional<unsigned> Parser::ParseLambdaIntroducer(LambdaIntroducer &Intro)
   return DiagResult();
 }
 
-/// TryParseLambdaExpression - Tentatively parse a lambda introducer.
+/// TryParseLambdaIntroducer - Tentatively parse a lambda introducer.
 ///
 /// Returns true if it hit something unexpected.
 bool Parser::TryParseLambdaIntroducer(LambdaIntroducer &Intro) {
@@ -673,8 +673,20 @@ bool Parser::TryParseLambdaIntroducer(LambdaIntroducer &Intro) {
 /// expression.
 ExprResult Parser::ParseLambdaExpressionAfterIntroducer(
                      LambdaIntroducer &Intro) {
+  ExprResult MaybeLambda = Actions.ActOnLambdaIntroducer(getCurScope(), Intro);
+  if (!MaybeLambda.isUsable())
+    return ExprError();
+
+  LambdaExpr *Lambda = reinterpret_cast<LambdaExpr*>(MaybeLambda.take());
+
   // Parse lambda-declarator[opt].
   DeclSpec DS(AttrFactory);
+  {
+    const char *PrevSpec = 0;
+    unsigned DiagID = 0;
+    bool HasPrevSpec = DS.SetTypeSpecType(TST_auto, /*Loc=*/SourceLocation(), PrevSpec, DiagID);
+    assert(!HasPrevSpec && !PrevSpec && "unexpected default type specifier!");
+  }
   Declarator D(DS, Declarator::PrototypeContext);
 
   if (Tok.is(tok::l_paren)) {
@@ -748,6 +760,8 @@ ExprResult Parser::ParseLambdaExpressionAfterIntroducer(
                   Attr, DeclEndLoc);
   }
 
+  Actions.ActOnLambdaDeclarator(getCurScope(), Lambda, D);
+
   // Parse compound-statement.
   if (Tok.is(tok::l_brace)) {
     // FIXME: Rename BlockScope -> ClosureScope if we decide to continue using
@@ -759,6 +773,9 @@ ExprResult Parser::ParseLambdaExpressionAfterIntroducer(
     StmtResult Stmt(ParseCompoundStatementBody());
 
     BodyScope.Exit();
+
+    if (!Stmt.isInvalid())
+      Actions.ActOnLambdaBody(getCurScope(), Lambda, Stmt.take());
   } else {
     Diag(Tok, diag::err_expected_lambda_body);
   }
diff --git lib/Sema/SemaExprCXX.cpp lib/Sema/SemaExprCXX.cpp
index 428e728..337633e 100644
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -4655,3 +4655,381 @@ bool Sema::CheckMicrosoftIfExistsSymbol(CXXScopeSpec &SS,
   LookupParsedName(R, getCurScope(), &SS);
   return !R.empty(); 
 }
+
+// FIXME: Several areas in the below ActOnLambda* functions may benefit from
+// calling existing Sema functions, or from factoring out some essential bits to
+// share. These are marked with FIXMEs that begin "Compare with ...".
+//
+// Additionally, there are a few checks sprinkled throughout these actions
+// merely to ensure their correct implementation. I did not think it worth
+// wrapping them in separate functions just so they can be asserted. They should
+// be removed after code review for performance reasons. They are marked with
+// FIXMEs stating "Remove this check later.".
+ExprResult Sema::ActOnLambdaIntroducer(Scope *S, const LambdaIntroducer &Intro) {
+  // Diagnose and build the explicit capture list. Erroneous captures are
+  // skipped as if they did not exist.
+  SourceLocation CapturesThis;
+  llvm::DenseMap<const IdentifierInfo*, SourceLocation> CapturesSoFar;
+  llvm::SmallVector<LambdaExpr::Capture, 4> Explicits;
+
+  for (llvm::SmallVector<LambdaCapture, 4>::const_iterator
+       C = Intro.Captures.begin(), E = Intro.Captures.end(); C != E; ++C) {
+    if (C->Kind == LCK_This) {
+      if (CapturesThis.isValid()) {
+        Diag(C->Loc, diag::err_capture_more_than_once) << "'this'"
+          << CapturesThis;
+        continue;
+      }
+
+      if (Intro.Default == LCD_ByCopy) {
+        Diag(C->Loc, diag::err_this_capture_with_copy_default);
+        continue;
+      }
+
+      ExprResult ThisRes = ActOnCXXThis(C->Loc);
+      if (!ThisRes.isUsable()) {
+        // Already diagnosed the error.
+        continue;
+      }
+
+      CapturesThis = C->Loc;
+      CXXThisExpr *This = static_cast<CXXThisExpr*>(ThisRes.take());
+      Explicits.push_back(LambdaExpr::Capture(This));
+      continue;
+    }
+
+    assert(C->Id && "missing identifier for capture");
+
+    if (C->Kind == LCK_ByRef && Intro.Default == LCD_ByRef) {
+      Diag(C->Loc, diag::err_reference_capture_with_reference_default);
+      continue;
+    } else if (C->Kind == LCK_ByCopy && Intro.Default == LCD_ByCopy) {
+      Diag(C->Loc, diag::err_copy_capture_with_copy_default);
+      continue;
+    }
+
+    llvm::DenseMap<const IdentifierInfo*, SourceLocation>::iterator Appearance;
+    bool IsFirstAppearance;
+    llvm::tie(Appearance, IsFirstAppearance)
+      = CapturesSoFar.insert(std::make_pair(C->Id, C->Loc));
+
+    if (!IsFirstAppearance) {
+      Diag(C->Loc, diag::err_capture_more_than_once) << C->Id
+        << Appearance->second;
+      continue;
+    }
+
+    UnqualifiedId Name;
+    CXXScopeSpec ScopeSpec;
+    Name.setIdentifier(C->Id, C->Loc);
+    DeclRefExpr *VarRef
+      = static_cast<DeclRefExpr*>(
+          ActOnIdExpression(S, ScopeSpec, Name,
+                            /*HasTrailingLParen=*/false,
+                            /*IsAddressOfOperand=*/false).take());
+
+    // Check that we have a local variable with automatic storage duration.
+    if (VarDecl *Var = dyn_cast<VarDecl>(VarRef->getDecl())) {
+      if (!Var->hasLocalStorage() || Var->getStorageClass() == SC_Register)
+        Diag(C->Loc, diag::err_capture_non_automatic_variable) << C->Id;
+    } else {
+      Diag(C->Loc, diag::err_capture_does_not_name_variable) << C->Id;
+    }
+
+    Explicits.push_back(
+      LambdaExpr::Capture(VarRef, C->Kind == LCK_ByRef));
+  }
+
+  // Find the nearest block, class, or namespace scope.
+  DeclContext *DC = CurContext;
+  while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isNamespace()))
+    DC = DC->getParent();
+
+  CXXRecordDecl *Class = CXXRecordDecl::Create(Context,
+                                               TTK_Class,
+                                               DC,
+                                               Intro.Range.getBegin(),
+                                               /*IdLoc=*/SourceLocation(),
+                                               /*Id=*/0);
+  Class->startDefinition();
+  // FIXME: This is how we track the end of the lambda. It is set repeatedly as
+  // we move along. Is it ok?
+  // FIXME: We've got Decl::getSourceRange (that splits into Decl::getLocStart
+  // and Decl::getLocEnd), Decl::getLocation, and Decl::getBodyRBrace;
+  // DeclaratorDecl::getInnerLocStart and DeclaratorDecl::getOuterLocStart;
+  // TagDecl::getRBraceLoc. Some of these do not have corresponding setters,
+  // some do---even in other subclasses, e.g., FunctionDecl::setRangeEnd.
+  // How are they related? I have a feeling some redundancy exists.
+  Class->setRBraceLoc(Intro.Range.getEnd());
+
+  LambdaExpr *Lambda = LambdaExpr::Create(Context, Class,
+                                          Explicits.data(), Explicits.size());
+
+  return ExprResult(Lambda);
+}
+
+void Sema::ActOnLambdaDeclarator(Scope *S, LambdaExpr *Lambda, Declarator &D) {
+  CXXRecordDecl *Class = Lambda->getClosureType();
+  Class->setRBraceLoc(D.getSourceRange().getEnd());
+
+  QualType MethodTy;
+  TypeSourceInfo *MethodTyInfo;
+  if (D.getNumTypeObjects() == 0) {
+    MethodTy = Context.getFunctionType(Context.VoidTy,
+                                       /*Args=*/0,
+                                       /*NumArgs=*/0,
+                                       FunctionProtoType::ExtProtoInfo());
+    MethodTyInfo = Context.getTrivialTypeSourceInfo(MethodTy);
+  } else {
+    assert(D.isFunctionDeclarator() && "non-function lambda-declarator!");
+    DeclaratorChunk::FunctionTypeInfo &Fun = D.getFunctionTypeInfo();
+    if (!Fun.TrailingReturnType) {
+      Fun.TrailingReturnType = Context.VoidTy.getAsOpaquePtr();
+    }
+    // FIXME: The scope is unused?
+    MethodTyInfo = GetTypeForDeclarator(D, S);
+    // FIXME: Unsure of how to deal with this error. Any problems building the
+    // DeclaratorChunk should have been dealt with earlier, correct? I expect
+    // that we would have a void() function type at worst.
+    // If we can fail here, then probably need to return true to indicate
+    // failure, and have the caller in Parser skip over the rest of the
+    // expression and return ExprError.
+    assert(MethodTyInfo && "no type from lambda-declarator!");
+    MethodTy = MethodTyInfo->getType();
+  }
+
+  assert(MethodTy->isFunctionType() &&
+         "no function type from lambda-declarator!");
+  DeclarationName MethodName
+    = Context.DeclarationNames.getCXXOperatorName(OO_Call);
+  CXXMethodDecl *Method
+    = CXXMethodDecl::Create(Context,
+                            Class,
+                            D.getSourceRange().getBegin(),
+                            DeclarationNameInfo(MethodName,
+                                                /*NameLoc=*/SourceLocation()),
+                            MethodTy,
+                            MethodTyInfo,
+                            /*isStatic=*/false,
+                            SC_None,
+                            /*isInline=*/true,
+                            /*isConstExpr=*/false,
+                            D.getSourceRange().getEnd());
+  Method->setAccess(AS_public);
+  Method->setLexicalDeclContext(CurContext);
+  // FIXME: How to add Method as a member of Class? Cannot use
+  // DeclContext::addDecl. Apparently, that is only for lexical contexts.  How
+  // should we handle DeclContexts for Class, Method, Field, and Ctor?
+
+  assert(isa<FunctionProtoTypeLoc>(MethodTyInfo->getTypeLoc()) &&
+         "no function type from lambda-declarator!");
+  FunctionProtoTypeLoc MethodTypeLoc
+    = cast<FunctionProtoTypeLoc>(MethodTyInfo->getTypeLoc());
+  Method->setParams(MethodTypeLoc.getParmArray(), MethodTypeLoc.getNumArgs());
+
+  // FIXME: Remove this check later.
+  bool Redeclaration = false;
+  LookupResult Previous(*this,
+                        MethodName,
+                        SourceLocation(),
+                        LookupOrdinaryName,
+                        ForRedeclaration);
+  CheckFunctionDeclaration(S, Method, Previous,
+                           /*IsExplicitSpecialization=*/false,
+                           Redeclaration);
+  assert(!Method->isInvalidDecl() && "bad lambda constructor");
+
+  Lambda->setFunction(Method);
+}
+
+void Sema::ActOnLambdaBody(Scope *S, LambdaExpr *Lambda, Stmt *Body) {
+  CXXRecordDecl *Class = Lambda->getClosureType();
+  Class->setRBraceLoc(Body->getLocEnd());
+
+  CanQualType ClassType
+    = Context.getCanonicalType(Context.getRecordType(Class));
+
+  CXXMethodDecl *Method = Lambda->getFunction();
+  Method->setBody(Body);
+
+  DeclarationName CtorName
+    = Context.DeclarationNames.getCXXConstructorName(ClassType);
+  CXXConstructorDecl *Ctor
+    = CXXConstructorDecl::Create(Context,
+                                 Class,
+                                 /*StartLoc=*/SourceLocation(),
+                                 DeclarationNameInfo(CtorName,
+                                                  /*NameLoc=*/SourceLocation()),
+                                 // Chicken and egg problem: we need the Ctor to
+                                 // build the CtorParams and the CtorParams to
+                                 // build the Ctor. Favor one call on the Ctor
+                                 // to set its type after construction instead
+                                 // of one call on each CtorParam to set their
+                                 // DeclContext.
+                                 QualType(),
+                                 /*TInfo=*/0,
+                                 /*isExplicit=*/true,
+                                 /*isInline=*/true,
+                                 /*isImplicitlyDeclared=*/true,
+                                 /*isConstExpr=*/false);
+
+  // FIXME: When we support implicit captures later, this number will need to be
+  // updated.
+  unsigned NumCaptures = Lambda->getNumExplicits();
+
+  llvm::SmallVector<QualType, 4> CtorParamTys;
+  CtorParamTys.reserve(NumCaptures);
+  llvm::SmallVector<ParmVarDecl*, 4> CtorParams;
+  CtorParams.reserve(NumCaptures);
+  CXXCtorInitializer **CtorInits
+    = new (Context) CXXCtorInitializer*[NumCaptures];
+  llvm::SmallVector<Expr*, 4> CtorArgs;
+  CtorArgs.reserve(NumCaptures);
+
+
+  CXXCtorInitializer **CtorInit = CtorInits;
+  for (LambdaExpr::capture_const_iterator C = Lambda->explicits_begin(),
+       E = Lambda->explicits_end(); C != E; ++C) {
+
+    Expr *Init = C->getInit();
+
+    IdentifierInfo *Id;
+    if (C->isThisCapture()) {
+      Id = PP.getIdentifierInfo("__this");
+    } else {
+      Id = cast<DeclRefExpr>(Init)->getDecl()->getIdentifier();
+    }
+
+    SourceLocation CaptureLoc = C->getLoc();
+    DeclarationName CaptureName
+      = Context.DeclarationNames.getIdentifier(Id);
+
+    // FIXME: Find the correct type. There are capture type transformations
+    // remaining to be implemented. What is the difference between CanQualType
+    // and QualType? How is template instantiation handled? If some of these
+    // have dependent type, how is that treated?
+    QualType CaptureType = Init->getType();
+    if (C->isReferenceCapture()) {
+      // FIXME: Compare with Sema::BuildReferenceType.
+      CaptureType = Context.getLValueReferenceType(CaptureType,
+                                                   /*SpelledAsLValue=*/true);
+    }
+
+    FieldDecl *Field = CheckFieldDecl(CaptureName,
+                                      CaptureType,
+                                      /*TInfo=*/0,
+                                      Class,
+                                      CaptureLoc,
+                                      /*Mutable=*/false,
+                                      /*BitWidth=*/0,
+                                      /*HasInit=*/false,
+                                      // FIXME: Pass IdLoc? We haven't for other
+                                      // declarations so far, but fields are the
+                                      // only ones we have names for in the
+                                      // source.
+                                      CaptureLoc,
+                                      AS_private,
+                                      /*PrevDecl=*/0);
+
+    Class->addDecl(Field);
+
+    // FIXME: Compare with Sema::CheckParameter.
+    ParmVarDecl *CtorParam = ParmVarDecl::Create(Context,
+                                                 Ctor,
+                                                 CaptureLoc,
+                                                 CaptureLoc,
+                                                 Id,
+                                  Context.getAdjustedParameterType(CaptureType),
+                                                 /*TInfo=*/0,
+                                                 SC_None,
+                                                 SC_None,
+                                                 /*DefArg=*/0);
+
+    CtorParamTys.push_back(CaptureType);
+    CtorParams.push_back(CtorParam);
+
+    {
+      // FIXME: Have to use Expr* instead of DeclRefExpr* because we cannot
+      // convert from DeclRefExpr** to Expr**. Why?
+      Expr *CtorInitArg
+        = DeclRefExpr::Create(Context,
+                              /*QualifierLoc=*/NestedNameSpecifierLoc(),
+                              CtorParam,
+                              CaptureLoc,
+                              CaptureType.getNonReferenceType(),
+                              VK_LValue);
+
+      MemInitResult Res = BuildMemberInitializer(Field,
+                                                 &CtorInitArg,
+                                                 /*NumArgs=*/1u,
+                                                 CaptureLoc,
+                                                 /*L=*/SourceLocation(),
+                                                 /*R=*/SourceLocation());
+
+      // FIXME: If there was an error, it is probably a bug, right?
+      assert(Res.isUsable() && "bad member initializer!");
+      *CtorInit = Res.take();
+      ++CtorInit;
+    }
+
+    CtorArgs.push_back(Init);
+  }
+
+  assert(CtorParamTys.size() == NumCaptures &&
+         "missed a constructor parameter type!");
+  assert(CtorParams.size() == NumCaptures && "missed a constructor parameter!");
+  assert(CtorArgs.size() == NumCaptures && "missed a constructor argument!");
+
+  // FIXME: Compare with Sema::BuildFunctionType.
+  QualType CtorType = Context.getFunctionType(Context.VoidTy,
+                                              CtorParamTys.data(),
+                                              CtorParamTys.size(),
+                                              FunctionProtoType::ExtProtoInfo());
+
+  Ctor->setAccess(AS_public);
+  Ctor->setImplicit();
+  Ctor->setType(CtorType);
+  // FIXME: Compare with Sema::CheckParmsForFunctionDef.
+  Ctor->setParams(CtorParams.data(), CtorParams.size());
+  // FIXME: Compare with Sema::ActOnMemInitializers.
+  // FIXME: Compare with Sema::SetCtorInitializers.
+  Ctor->setNumCtorInitializers(NumCaptures);
+  Ctor->setCtorInitializers(CtorInits);
+
+  // FIXME: Remove this check later.
+  bool Redeclaration = false;
+  LookupResult Previous(*this,
+                        CtorName,
+                        SourceLocation(),
+                        LookupOrdinaryName,
+                        ForRedeclaration);
+  CheckFunctionDeclaration(S, Ctor, Previous,
+                           /*IsExplicitSpecialization=*/false,
+                           Redeclaration);
+  assert(!Ctor->isInvalidDecl() && "bad lambda constructor");
+
+  Class->addDecl(Ctor);
+
+  Class->completeDefinition();
+  // FIXME: Remove this check later.
+  CheckCompletedCXXClass(Class);
+
+  {
+    ExprResult Res = BuildCXXConstructExpr(Lambda->getLocStart(),
+                                           CtorType,
+                                           Ctor,
+                                           /*Elidable=*/false,
+                                           MultiExprArg(CtorArgs.data(),
+                                                        CtorArgs.size()),
+                                           /*RequiresZeroInit=*/false,
+                                           CXXConstructExpr::CK_Complete,
+                                           /*ParenRange=*/SourceRange());
+
+    // If there was an error, then we probably have a bug.
+    assert(Res.isUsable() && "bad lambda construction!");
+
+    CXXConstructExpr *CtorCall = Res.takeAs<CXXConstructExpr>();
+    Lambda->setClosureObject(CtorCall);
+  }
+}
+
diff --git lib/Sema/TreeTransform.h lib/Sema/TreeTransform.h
index 12eba29..5336bca 100644
--- lib/Sema/TreeTransform.h
+++ lib/Sema/TreeTransform.h
@@ -7932,6 +7932,14 @@ TreeTransform<Derived>::TransformShuffleVectorExpr(ShuffleVectorExpr *E) {
                                                E->getRParenLoc());
 }
 
+// FIXME: Implement.
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformLambdaExpr(LambdaExpr *E) {
+  llvm_unreachable("unimplemented");
+  return ExprEmpty();
+}
+
 template<typename Derived>
 ExprResult
 TreeTransform<Derived>::TransformBlockExpr(BlockExpr *E) {
diff --git lib/Serialization/ASTReaderStmt.cpp lib/Serialization/ASTReaderStmt.cpp
index a402ad0..d969809 100644
--- lib/Serialization/ASTReaderStmt.cpp
+++ lib/Serialization/ASTReaderStmt.cpp
@@ -741,6 +741,11 @@ void ASTStmtReader::VisitShuffleVectorExpr(ShuffleVectorExpr *E) {
   E->setRParenLoc(ReadSourceLocation(Record, Idx));
 }
 
+// FIXME: Implement.
+void ASTStmtReader::VisitLambdaExpr(LambdaExpr *E) {
+  llvm_unreachable("unimplemented");
+}
+
 void ASTStmtReader::VisitBlockExpr(BlockExpr *E) {
   VisitExpr(E);
   E->setBlockDecl(ReadDeclAs<BlockDecl>(Record, Idx));
diff --git lib/Serialization/ASTWriterStmt.cpp lib/Serialization/ASTWriterStmt.cpp
index 8f68b12..3f8a54f 100644
--- lib/Serialization/ASTWriterStmt.cpp
+++ lib/Serialization/ASTWriterStmt.cpp
@@ -701,6 +701,11 @@ void ASTStmtWriter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) {
   Code = serialization::EXPR_SHUFFLE_VECTOR;
 }
 
+// FIXME: Implement.
+void ASTStmtWriter::VisitLambdaExpr(LambdaExpr *E) {
+  llvm_unreachable("unimplemented");
+}
+
 void ASTStmtWriter::VisitBlockExpr(BlockExpr *E) {
   VisitExpr(E);
   Writer.AddDeclRef(E->getBlockDecl(), Record);
diff --git test/Parser/objcxx0x-lambda-expressions.mm test/Parser/objcxx0x-lambda-expressions.mm
index d100e2e..8d2d9f6 100644
--- test/Parser/objcxx0x-lambda-expressions.mm
+++ test/Parser/objcxx0x-lambda-expressions.mm
@@ -9,7 +9,7 @@ class C {
     [foo,+] {}; // expected-error {{expected expression}}
 
     []; // expected-error {{expected body of lambda expression}}
-    [=,foo+] {}; // expected-error {{expected ',' or ']' in lambda capture list}}
+    [=,&foo+] {}; // expected-error {{expected ',' or ']' in lambda capture list}}
     [&this] {}; // expected-error {{address expression must be an lvalue}}
     [] {};
     [=] (int i) {};
diff --git test/SemaCXX/lambda-expressions.cpp test/SemaCXX/lambda-expressions.cpp
new file mode 100644
index 0000000..306af7b
--- /dev/null
+++ test/SemaCXX/lambda-expressions.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -std=c++0x -fsyntax-only -verify %s
+
+class C {
+  void f() {
+    int foo;
+
+    [foo, foo] () {}; // expected-error {{'foo' can appear only once}}
+    [this, this] () {}; // expected-error {{'this' can appear only once}}
+    [=, foo] () {}; // expected-error {{'&' must precede a capture when}}
+    [=, &foo] () {};
+    [=, this] () {}; // expected-error {{'this' cannot appear}}
+    [&, foo] () {};
+    [&, &foo] () {}; // expected-error {{'&' cannot precede a capture when}}
+    [&, this] () {};
+
+    [] () -> bool {
+      return true; // expected-error {{should not return a value}}
+    };
+  }
+};
+
