From c5dc285ca547924f02910e4fee5290bffbed3a14 Mon Sep 17 00:00:00 2001
From: Sergey Prigogin <eclipse.sprigogin@gmail.com>
Date: Tue, 14 Mar 2017 20:25:23 -0700
Subject: [PATCH] Bug 513681 - Unresolved name with a friend declaration in a
 namespace

Change-Id: I778886f802576a9b8d7804eb32abfe091bf0568d
---
 .../parser/tests/ast2/AST2TemplateTests.java  | 20 +++++++++++
 .../index/tests/IndexMultiFileTest.java       | 33 +++++++++++++++++++
 .../parser/cpp/semantics/CPPTemplates.java    | 13 ++++++--
 3 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java
index 6e32e8aa394..4c4ac69fa2a 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java
@@ -10160,4 +10160,24 @@ public class AST2TemplateTests extends AST2TestBase {
 	public void testNoexceptSpecifierInTypeTemplateArgument_511186() throws Exception {
 		parseAndCheckBindings();
 	}
+
+	//	namespace ns {
+	//
+	//	template <typename T>
+	//	class A {
+	//	  friend void waldo(A<int> flag);
+	//	};
+	//
+	//	void waldo(A<int> flag);
+	//
+	//	}
+	//
+	//	ns::A<int> a;
+	//
+	//	void func() {
+	//	  waldo(a);
+	//	}
+	public void testFriendFunctionDeclarationInNamespace_513681() throws Exception {
+		parseAndCheckBindings();
+	}
 }
diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexMultiFileTest.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexMultiFileTest.java
index e05c33ed74e..0e9481bebb0 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexMultiFileTest.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexMultiFileTest.java
@@ -268,4 +268,37 @@ public class IndexMultiFileTest extends IndexBindingResolutionTestBase {
 		// This code is invalid, so we don't checkBindings().
 		// If the test gets this far (doesn't throw in setup() during indexing), it passes.
 	}
+
+	// test.h
+	//	namespace ns {
+	//
+	//	template <typename T>
+	//	class A {
+	//	  friend void waldo(A<int> p);
+	//	};
+	//
+	//	void waldo(A<int> p);
+	//
+	//	}
+
+	// test.cpp *
+	//	#include "test.h"
+	//
+	//	ns::A<int> b;
+	//
+	//	void test() {
+	//	  ns::waldo(b);
+	//	}
+
+	// z.cpp
+	//	#include "test.h"
+	//
+	//	ns::A<int> a;
+	//
+	//	void func() {
+	//	  waldo(a);
+	//	}
+	public void testFriendFunctionDeclarationInNamespace_513681() throws Exception {
+		checkBindings();
+	}
 }
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPTemplates.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPTemplates.java
index 7d35f33ce15..3bf437daac2 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPTemplates.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPTemplates.java
@@ -1105,14 +1105,21 @@ public class CPPTemplates {
 				} else if (decl instanceof ICPPMethod && classOwner != null) {
 					functionSpec = new CPPMethodSpecialization((ICPPMethod) decl, classOwner, tpMap, type, exceptionSpecs);
 				} else if (decl instanceof ICPPFunction) {
-					IBinding oldOwner = decl.getOwner();
-					functionSpec = new CPPFunctionSpecialization((ICPPFunction) decl, oldOwner, tpMap, type, exceptionSpecs);
+					if (type.isSameType(func.getType())) {
+						// There is no need to create a CPPFunctionSpecialization object since the function is
+						// a friend function with the type that is not affected by the specialization.
+						// See http://bugs.eclipse.org/513681
+						spec = func;
+					} else {
+						IBinding oldOwner = decl.getOwner();
+						functionSpec = new CPPFunctionSpecialization(func, oldOwner, tpMap, type, exceptionSpecs);
+					}
 				}
 				if (functionSpec != null) {
 					functionSpec.setParameters(specializeParameters(func.getParameters(), functionSpec, context,
 							IntegralValue.MAX_RECURSION_DEPTH));
+					spec = functionSpec;
 				}
-				spec = functionSpec;
 			} else if (decl instanceof ITypedef) {
 				InstantiationContext context = createInstantiationContext(tpMap, owner, point);
 				IType type= instantiateType(((ITypedef) decl).getType(), context);