1 files changed, 55 insertions, 39 deletions

diff --git a/lib/Sema/SemaLambda.cpp b/lib/Sema/SemaLambda.cpp
index 884add26e43a..1b8410d7f4b9 100644
--- a/lib/Sema/SemaLambda.cpp
+++ b/lib/Sema/SemaLambda.cpp
@@ -355,7 +355,8 @@ CXXMethodDecl *Sema::startLambdaDefinition(CXXRecordDecl *Class,
                                            SourceRange IntroducerRange,
                                            TypeSourceInfo *MethodTypeInfo,
                                            SourceLocation EndLoc,
-                                           ArrayRef<ParmVarDecl *> Params) {
+                                           ArrayRef<ParmVarDecl *> Params,
+                                           const bool IsConstexprSpecified) {
   QualType MethodType = MethodTypeInfo->getType();
   TemplateParameterList *TemplateParams = 
             getGenericLambdaTemplateParameterList(getCurLambda(), *this);
@@ -392,7 +393,7 @@ CXXMethodDecl *Sema::startLambdaDefinition(CXXRecordDecl *Class,
                             MethodType, MethodTypeInfo,
                             SC_None,
                             /*isInline=*/true,
-                            /*isConstExpr=*/false,
+                            IsConstexprSpecified,
                             EndLoc);
   Method->setAccess(AS_public);
   
@@ -414,11 +415,10 @@ CXXMethodDecl *Sema::startLambdaDefinition(CXXRecordDecl *Class,
   // Add parameters.
   if (!Params.empty()) {
     Method->setParams(Params);
-    CheckParmsForFunctionDef(const_cast<ParmVarDecl **>(Params.begin()),
-                             const_cast<ParmVarDecl **>(Params.end()),
+    CheckParmsForFunctionDef(Params,
                              /*CheckParameterNames=*/false);
-    
-    for (auto P : Method->params())
+
+    for (auto P : Method->parameters())
       P->setOwningFunction(Method);
   }
 
@@ -617,6 +617,8 @@ void Sema::deduceClosureReturnType(CapturingScopeInfo &CSI) {
   assert(CSI.HasImplicitReturnType);
   // If it was ever a placeholder, it had to been deduced to DependentTy.
   assert(CSI.ReturnType.isNull() || !CSI.ReturnType->isUndeducedType()); 
+  assert((!isa<LambdaScopeInfo>(CSI) || !getLangOpts().CPlusPlus14) &&
+         "lambda expressions use auto deduction in C++14 onwards");
 
   // C++ core issue 975:
   //   If a lambda-expression does not include a trailing-return-type,
@@ -807,19 +809,13 @@ void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
   bool KnownDependent = false;
   LambdaScopeInfo *const LSI = getCurLambda();
   assert(LSI && "LambdaScopeInfo should be on stack!");
-  TemplateParameterList *TemplateParams = 
-            getGenericLambdaTemplateParameterList(LSI, *this);
-
-  if (Scope *TmplScope = CurScope->getTemplateParamParent()) {
-    // Since we have our own TemplateParams, so check if an outer scope
-    // has template params, only then are we in a dependent scope.
-    if (TemplateParams)  {
-      TmplScope = TmplScope->getParent();
-      TmplScope = TmplScope ? TmplScope->getTemplateParamParent() : nullptr;
-    }
-    if (TmplScope && !TmplScope->decl_empty())
-      KnownDependent = true;
-  }
+
+  // The lambda-expression's closure type might be dependent even if its
+  // semantic context isn't, if it appears within a default argument of a
+  // function template.
+  if (CurScope->getTemplateParamParent())
+    KnownDependent = true;
+
   // Determine the signature of the call operator.
   TypeSourceInfo *MethodTyInfo;
   bool ExplicitParams = true;
@@ -882,8 +878,9 @@ void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
   CXXRecordDecl *Class = createLambdaClosureType(Intro.Range, MethodTyInfo,
                                                  KnownDependent, Intro.Default);
 
-  CXXMethodDecl *Method = startLambdaDefinition(Class, Intro.Range,
-                                                MethodTyInfo, EndLoc, Params);
+  CXXMethodDecl *Method =
+      startLambdaDefinition(Class, Intro.Range, MethodTyInfo, EndLoc, Params,
+                            ParamInfo.getDeclSpec().isConstexprSpecified());
   if (ExplicitParams)
     CheckCXXDefaultArguments(Method);
   
@@ -922,7 +919,12 @@ void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
     = Intro.Default == LCD_None? Intro.Range.getBegin() : Intro.DefaultLoc;
   for (auto C = Intro.Captures.begin(), E = Intro.Captures.end(); C != E;
        PrevCaptureLoc = C->Loc, ++C) {
-    if (C->Kind == LCK_This) {
+    if (C->Kind == LCK_This || C->Kind == LCK_StarThis) {
+      if (C->Kind == LCK_StarThis) 
+        Diag(C->Loc, !getLangOpts().CPlusPlus1z
+                             ? diag::ext_star_this_lambda_capture_cxx1z
+                             : diag::warn_cxx14_compat_star_this_lambda_capture);
+
       // C++11 [expr.prim.lambda]p8:
       //   An identifier or this shall not appear more than once in a 
       //   lambda-capture.
@@ -934,10 +936,12 @@ void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
         continue;
       }
 
-      // C++11 [expr.prim.lambda]p8:
-      //   If a lambda-capture includes a capture-default that is =, the 
-      //   lambda-capture shall not contain this [...].
-      if (Intro.Default == LCD_ByCopy) {
+      // C++1z [expr.prim.lambda]p8:
+      //  If a lambda-capture includes a capture-default that is =, each
+      //  simple-capture of that lambda-capture shall be of the form "&
+      //  identifier" or "* this". [ Note: The form [&,this] is redundant but
+      //  accepted for compatibility with ISO C++14. --end note ]
+      if (Intro.Default == LCD_ByCopy && C->Kind != LCK_StarThis) {
         Diag(C->Loc, diag::err_this_capture_with_copy_default)
             << FixItHint::CreateRemoval(
                 SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
@@ -953,7 +957,9 @@ void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
         continue;
       }
       
-      CheckCXXThisCapture(C->Loc, /*Explicit=*/true);
+      CheckCXXThisCapture(C->Loc, /*Explicit=*/true, /*BuildAndDiagnose*/ true,
+                          /*FunctionScopeIndexToStopAtPtr*/ nullptr,
+                          C->Kind == LCK_StarThis);
       continue;
     }
 
@@ -1144,8 +1150,8 @@ static void addFunctionPointerConversion(Sema &S,
                                          CXXMethodDecl *CallOperator) {
   // This conversion is explicitly disabled if the lambda's function has
   // pass_object_size attributes on any of its parameters.
-  if (std::any_of(CallOperator->param_begin(), CallOperator->param_end(),
-                  std::mem_fn(&ParmVarDecl::hasAttr<PassObjectSizeAttr>)))
+  if (llvm::any_of(CallOperator->parameters(),
+                   std::mem_fn(&ParmVarDecl::hasAttr<PassObjectSizeAttr>)))
     return;
 
   // Add the conversion to function pointer.
@@ -1493,7 +1499,7 @@ ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
   SourceRange IntroducerRange;
   bool ExplicitParams;
   bool ExplicitResultType;
-  bool LambdaExprNeedsCleanups;
+  CleanupInfo LambdaCleanup;
   bool ContainsUnexpandedParameterPack;
   SmallVector<VarDecl *, 4> ArrayIndexVars;
   SmallVector<unsigned, 4> ArrayIndexStarts;
@@ -1503,7 +1509,7 @@ ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
     IntroducerRange = LSI->IntroducerRange;
     ExplicitParams = LSI->ExplicitParams;
     ExplicitResultType = !LSI->HasImplicitReturnType;
-    LambdaExprNeedsCleanups = LSI->ExprNeedsCleanups;
+    LambdaCleanup = LSI->Cleanup;
     ContainsUnexpandedParameterPack = LSI->ContainsUnexpandedParameterPack;
     
     CallOperator->setLexicalDeclContext(Class);
@@ -1527,10 +1533,9 @@ ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
       // Handle 'this' capture.
       if (From.isThisCapture()) {
         Captures.push_back(
-            LambdaCapture(From.getLocation(), IsImplicit, LCK_This));
-        CaptureInits.push_back(new (Context) CXXThisExpr(From.getLocation(),
-                                                         getCurrentThisType(),
-                                                         /*isImplicit=*/true));
+            LambdaCapture(From.getLocation(), IsImplicit,
+                          From.isCopyCapture() ? LCK_StarThis : LCK_This));
+        CaptureInits.push_back(From.getInitExpr());
         ArrayIndexStarts.push_back(ArrayIndexVars.size());
         continue;
       }
@@ -1585,9 +1590,8 @@ ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
     CheckCompletedCXXClass(Class);
   }
 
-  if (LambdaExprNeedsCleanups)
-    ExprNeedsCleanups = true;
-  
+  Cleanup.mergeFrom(LambdaCleanup);
+
   LambdaExpr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange, 
                                           CaptureDefault, CaptureDefaultLoc,
                                           Captures, 
@@ -1595,6 +1599,17 @@ ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
                                           CaptureInits, ArrayIndexVars, 
                                           ArrayIndexStarts, EndLoc,
                                           ContainsUnexpandedParameterPack);
+  // If the lambda expression's call operator is not explicitly marked constexpr
+  // and we are not in a dependent context, analyze the call operator to infer
+  // its constexpr-ness, supressing diagnostics while doing so.
+  if (getLangOpts().CPlusPlus1z && !CallOperator->isInvalidDecl() &&
+      !CallOperator->isConstexpr() &&
+      !Class->getDeclContext()->isDependentContext()) {
+    TentativeAnalysisScope DiagnosticScopeGuard(*this);
+    CallOperator->setConstexpr(
+        CheckConstexprFunctionDecl(CallOperator) &&
+        CheckConstexprFunctionBody(CallOperator, CallOperator->getBody()));
+  }
 
   if (!CurContext->isDependentContext()) {
     switch (ExprEvalContexts.back().Context) {
@@ -1619,6 +1634,7 @@ ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
       ExprEvalContexts.back().Lambdas.push_back(Lambda);
       break;
 
+    case DiscardedStatement:
     case PotentiallyEvaluated:
     case PotentiallyEvaluatedIfUsed:
       break;
@@ -1697,7 +1713,7 @@ ExprResult Sema::BuildBlockForLambdaConversion(SourceLocation CurrentLocation,
   // Create the block literal expression.
   Expr *BuildBlock = new (Context) BlockExpr(Block, Conv->getConversionType());
   ExprCleanupObjects.push_back(Block);
-  ExprNeedsCleanups = true;
+  Cleanup.setExprNeedsCleanups(true);
 
   return BuildBlock;
 }