Replace the broken LambdaCapture::isInitCapture API.

A LambdaCapture does not have sufficient information
to correctly determine whether it is an init-capture or not.
Doing so requires knowledge held in the LambdaExpr itself.

It the case of a nested capture of an init-capture it is not
sufficient to check (as LambdaCapture::isInitCapture did)
whether the associated VarDecl was from an init-capture.

This patch moves isInitCapture to LambdaExpr and updates
Capture->isInitCapture() to Lambda->isInitCapture(Capture).

llvm-svn: 236760

clang/include/clang/AST/DataRecursiveASTVisitor.h

@@ -791,7 +791,7 @@ template <typename Derived>
 bool
 RecursiveASTVisitor<Derived>::TraverseLambdaCapture(LambdaExpr *LE,
                                                     const LambdaCapture *C) {
-  if (C->isInitCapture())
+  if (LE->isInitCapture(C))
     TRY_TO(TraverseDecl(C->getCapturedVar()));
   return true;
 }

clang/include/clang/AST/ExprCXX.h

@@ -1452,6 +1452,9 @@ public:
     return CaptureDefaultLoc;
   }
 
+  /// \brief Determine whether one of this lambda's captures is an init-capture.
+  bool isInitCapture(const LambdaCapture *Capture) const;
+
   /// \brief An iterator that walks over the captures of the lambda,
   /// both implicit and explicit.
   typedef const Capture *capture_iterator;

clang/include/clang/AST/LambdaCapture.h

@@ -85,11 +85,6 @@ public:
            (DeclAndBits.getInt() & Capture_ByCopy);
   }
 
-  /// \brief Determine whether this is an init-capture.
-  bool isInitCapture() const {
-    return capturesVariable() && getCapturedVar()->isInitCapture();
-  }
-
   /// \brief Retrieve the declaration of the local variable being
   /// captured.
   ///

clang/include/clang/AST/RecursiveASTVisitor.h

@@ -857,7 +857,7 @@ template <typename Derived>
 bool
 RecursiveASTVisitor<Derived>::TraverseLambdaCapture(LambdaExpr *LE,
                                                     const LambdaCapture *C) {
-  if (C->isInitCapture())
+  if (LE->isInitCapture(C))
     TRY_TO(TraverseDecl(C->getCapturedVar()));
   return true;
 }

clang/lib/AST/ExprCXX.cpp

@@ -1027,6 +1027,11 @@ LambdaExpr *LambdaExpr::CreateDeserialized(const ASTContext &C,
   return new (Mem) LambdaExpr(EmptyShell(), NumCaptures, NumArrayIndexVars > 0);
 }
 
+bool LambdaExpr::isInitCapture(const LambdaCapture *C) const {
+  return (C->capturesVariable() && C->getCapturedVar()->isInitCapture() &&
+          (getCallOperator() == C->getCapturedVar()->getDeclContext()));
+}
+
 LambdaExpr::capture_iterator LambdaExpr::capture_begin() const {
   return getLambdaClass()->getLambdaData().Captures;
 }

clang/lib/AST/StmtPrinter.cpp

@@ -1758,7 +1758,7 @@ void StmtPrinter::VisitLambdaExpr(LambdaExpr *Node) {
       break;
 
     case LCK_ByRef:
-      if (Node->getCaptureDefault() != LCD_ByRef || C->isInitCapture())
+      if (Node->getCaptureDefault() != LCD_ByRef || Node->isInitCapture(C))
         OS << '&';
       OS << C->getCapturedVar()->getName();
       break;
@@ -1770,7 +1770,7 @@ void StmtPrinter::VisitLambdaExpr(LambdaExpr *Node) {
       llvm_unreachable("VLA type in explicit captures.");
     }
 
-    if (C->isInitCapture())
+    if (Node->isInitCapture(C))
       PrintExpr(C->getCapturedVar()->getInit());
   }
   OS << ']';

clang/lib/Sema/TreeTransform.h

@@ -9133,7 +9133,7 @@ TreeTransform<Derived>::TransformLambdaExpr(LambdaExpr *E) {
   for (LambdaExpr::capture_iterator C = E->capture_begin(),
                                     CEnd = E->capture_end();
        C != CEnd; ++C) {
-    if (!C->isInitCapture())
+    if (!E->isInitCapture(C))
       continue;
     EnterExpressionEvaluationContext EEEC(getSema(),
                                           Sema::PotentiallyEvaluated);
@@ -9245,7 +9245,7 @@ TreeTransform<Derived>::TransformLambdaExpr(LambdaExpr *E) {
       continue;
 
     // Rebuild init-captures, including the implied field declaration.
-    if (C->isInitCapture()) {
+    if (E->isInitCapture(C)) {
       InitCaptureInfoTy InitExprTypePair = 
           InitCaptureExprsAndTypes[C - E->capture_begin()];
       ExprResult Init = InitExprTypePair.first;

clang/test/SemaCXX/cxx1y-init-captures.cpp

@@ -166,4 +166,27 @@ int test(T t = T{}) {
 
 int run = test(); //expected-note {{instantiation}}
 
-}
+}
+
+namespace classification_of_captures_of_init_captures {
+
+template <typename T>
+void f() {
+  [a = 24] () mutable {
+    [&a] { a = 3; }();
+  }();
+}
+
+template <typename T>
+void h() {
+  [a = 24] (auto param) mutable {
+    [&a] { a = 3; }();
+  }(42);
+}
+
+int run() {
+  f<int>();
+  h<int>();
+}
+
+}