diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/cxx17/TemplateAutoTests.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/cxx17/TemplateAutoTests.java
index 17d86ac772e..c44bce54333 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/cxx17/TemplateAutoTests.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/cxx17/TemplateAutoTests.java
@@ -75,4 +75,37 @@ public class TemplateAutoTests extends AST2CPPTestBase {
 	public void testTemplateNontypeParameterTypeDeductionParsing_519361_3() throws Exception {
 		parseAndCheckBindings();
 	}
+
+	//	template <typename T, T>
+	//	struct meta { using type = int; };
+	//
+	//	template <typename T>
+	//	struct remove_noexcept { using type = T; };
+	//
+	//	template <typename T>
+	//	using remove_noexcept_t = typename remove_noexcept<T>::type;
+	//
+	//	template <auto Key>
+	//	struct K : meta<remove_noexcept_t<decltype(Key)>,Key>{};
+	//
+	//	template <auto Key>
+	//	struct W {
+	//	  using type = typename K<Key>::type;
+	//	};
+	//
+	//	template <typename T>
+	//	struct M {};
+	//
+	//	struct A {
+	//	    int foo;
+	//	};
+	//	typedef M<W<&A::foo>::type> M1; // typedef #1
+	//
+	//	struct B {
+	//	    int foo;
+	//	};
+	//	typedef M<W<&B::foo>::type> M2; // typedef #2
+	public void testInstantiationCacheConflict_553141() throws Exception {
+		parseAndCheckBindings();
+	}
 }
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/TypeInstantiationRequest.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/TypeInstantiationRequest.java
index e667de7196d..96d652981f5 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/TypeInstantiationRequest.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/TypeInstantiationRequest.java
@@ -80,7 +80,7 @@ public class TypeInstantiationRequest {
 			return true;
 		if (type1 == null || type2 == null)
 			return false;
-		return type1.isSameType(type1);
+		return type1.isSameType(type2);
 	}
 
 	private boolean equals(ICPPTemplateParameterMap map1, ICPPTemplateParameterMap map2) {