From 00980eb82ffc9799f5c5cbf5f41f27c270e3c259 Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Wed, 23 Mar 2016 20:07:07 +0000
Subject: [PATCH] Make sure to perform dependent access checks when
 instantiating a lambda-expression. We don't actually instantiate the closure
 type / operator() in the template in order to produce the closure type /
 operator() in the instantiation, so this isn't caught by the normal path.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@264184 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaLambda.cpp              | 19 +++++++------------
 lib/Sema/SemaTemplateInstantiate.cpp |  5 +++++
 test/SemaCXX/access.cpp              | 11 +++++++++++
 3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/lib/Sema/SemaLambda.cpp b/lib/Sema/SemaLambda.cpp
index 0f5eb41352..1dd37bd2d2 100644
--- a/lib/Sema/SemaLambda.cpp
+++ b/lib/Sema/SemaLambda.cpp
@@ -809,19 +809,14 @@ 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())
+
+  // 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 (Scope *TmplScope = CurScope->getTemplateParamParent())
+    if (!TmplScope->decl_empty())
       KnownDependent = true;
-  }
+
   // Determine the signature of the call operator.
   TypeSourceInfo *MethodTyInfo;
   bool ExplicitParams = true;
diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index 610817fcaf..42344e487c 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -729,6 +729,11 @@ namespace {
       }
       
       SemaRef.CurrentInstantiationScope->InstantiatedLocal(Old, New);
+
+      // We recreated a local declaration, but not by instantiating it. There
+      // may be pending dependent diagnostics to produce.
+      if (auto *DC = dyn_cast<DeclContext>(Old))
+        SemaRef.PerformDependentDiagnostics(DC, TemplateArgs);
     }
     
     /// \brief Transform the definition of the given declaration by
diff --git a/test/SemaCXX/access.cpp b/test/SemaCXX/access.cpp
index 5fa1509c53..cd65f907b8 100644
--- a/test/SemaCXX/access.cpp
+++ b/test/SemaCXX/access.cpp
@@ -158,3 +158,14 @@ namespace LocalExternVar {
 
   int array[sizeof(test::private_struct)]; // expected-error {{private}}
 }
+
+namespace ThisLambdaIsNotMyFriend {
+  class A {
+    friend class D;
+    static void foo(); // expected-note {{here}}
+  };
+  template <class T> void foo() {
+    []() { A::foo(); }(); // expected-error {{private}}
+  }
+  void bar() { foo<void>(); } // expected-note {{instantiation}}
+}
-- 
2.40.0