From 732c4874ee94ec65bd90b12d44f55d57585471bb Mon Sep 17 00:00:00 2001
From: Nathan Ridge <zeratul976@hotmail.com>
Date: Sat, 15 Sep 2018 23:33:08 -0400
Subject: [PATCH] Bug 539076 - Substitution of alias template for template
 template parameter

Change-Id: Ide5a6858560b0aae1efd391215bc229bef5421e7
---
 .../parser/tests/ast2/AST2TemplateTests.java  | 20 +++++++++++++++++++
 .../parser/cpp/semantics/CPPTemplates.java    | 12 ++++++++---
 2 files changed, 29 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 48a9cd6539a..96af705566e 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
@@ -10934,4 +10934,24 @@ public class AST2TemplateTests extends AST2CPPTestBase {
 	public void testMetaprogrammingWithAliasTemplates_534126() throws Exception {
 		parseAndCheckBindings();
 	}
+	
+	//	template <class>
+	//	struct hhh {
+	//	    using type = int;
+	//	};
+	//
+	//	template <template <class> class TT>
+	//	struct iii {
+	//	    using type = typename TT<int>::type;
+	//	};
+	//
+	//	template <class A>
+	//	using hhh_d = hhh<A>;
+	//
+	//	using waldo = typename iii<hhh_d>::type;
+	public void testAliasTemplateAsTemplateTemplateArg_539076() throws Exception {
+		BindingAssertionHelper helper = getAssertionHelper();
+		IType waldo = helper.assertNonProblem("waldo");
+		assertSameType(SemanticUtil.getSimplifiedType(waldo), CommonCPPTypes.int_);
+	}
 }
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 56f7c837cd7..89c30f2a77c 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
@@ -3113,9 +3113,15 @@ public class CPPTemplates {
 
 		boolean changed= arguments != newArgs;
 		IType classTemplateSpecialization= instantiateType(classTemplate, context);
-		if (classTemplateSpecialization != classTemplate && classTemplateSpecialization instanceof ICPPClassTemplate) {
-			classTemplate= (ICPPClassTemplate) classTemplateSpecialization;
-			changed= true;
+		if (classTemplateSpecialization != classTemplate) {
+			if (classTemplateSpecialization instanceof ICPPClassTemplate) {
+				classTemplate= (ICPPClassTemplate) classTemplateSpecialization;
+				changed= true;
+			} else if (classTemplateSpecialization instanceof ICPPAliasTemplate) {
+				IBinding inst = instantiateAliasTemplate((ICPPAliasTemplate) classTemplateSpecialization, newArgs);
+				if (inst != null)
+					return inst;
+			}
 		}
 
 		if (changed) {