diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2CPPTests.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2CPPTests.java
index 150c0c949f3..f52ecf91b20 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2CPPTests.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2CPPTests.java
@@ -10154,6 +10154,16 @@ public class AST2CPPTests extends AST2TestBase {
 	public void testIsBaseOf_399353() throws Exception {
 		parseAndCheckBindings(getAboveComment(), CPP, true);
 	}
+	
+	//	struct base {};
+	//	struct derived : base {};
+	//	typedef derived derived2;
+	//	const bool value = __is_base_of(base, derived2);
+	public void testIsBaseOf_409100() throws Exception {
+		BindingAssertionHelper b = getAssertionHelper();
+		IVariable var = b.assertNonProblem("value");
+		assertEquals(1 /*true */, var.getInitialValue().numericalValue().longValue());
+	}
 
 	//	template <bool> struct B{};
 	//	template <>
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/Value.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/Value.java
index 700f42d10e1..914bbee1cdb 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/Value.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/Value.java
@@ -69,12 +69,15 @@ import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.CPPTemplates;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.EvalBinary;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.EvalBinding;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.EvalFixed;
+import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.SemanticUtil;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.TypeTraits;
 import org.eclipse.cdt.internal.core.parser.scanner.ExpressionEvaluator;
 import org.eclipse.cdt.internal.core.parser.scanner.ExpressionEvaluator.EvalException;
 import org.eclipse.cdt.internal.core.pdom.db.TypeMarshalBuffer;
 import org.eclipse.core.runtime.CoreException;
 
+import static org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.SemanticUtil.TDEF;
+
 /**
  * Represents values of variables, enumerators or expressions. The primary purpose of
  * the representation is to support instantiation of templates with non-type template parameters.
@@ -349,6 +352,8 @@ public class Value implements IValue {
 			IType type1, IType type2, IASTNode point) {
 		switch (operator) {
 		case __is_base_of:
+			type1 = SemanticUtil.getNestedType(type1, TDEF);
+			type2 = SemanticUtil.getNestedType(type2, TDEF);
 			if (type1 instanceof ICPPClassType && type2 instanceof ICPPClassType) {
 				return ClassTypeHelper.isSubclass((ICPPClassType) type2, (ICPPClassType) type1) ? 1 : 0;
 			} else {