diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexCPPTemplateResolutionTest.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexCPPTemplateResolutionTest.java
index 86b1aafa0a9..304299688ec 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexCPPTemplateResolutionTest.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexCPPTemplateResolutionTest.java
@@ -2383,4 +2383,24 @@ public class IndexCPPTemplateResolutionTest extends IndexBindingResolutionTestBa
 	public void testAmbiguousBaseClassLookup_413406() throws Exception {
 		getProblemFromASTName("eof();", 3);
 	}
+
+	//	template <typename = void>
+	//	struct S;
+
+	//	#include "header.h"
+	//	template <>
+	//	struct S<void> {
+	//		typedef int type;
+	//	};
+	//
+	//	template <typename>
+	//	struct S {
+	//		typedef char type;
+	//	};
+	//
+	//	typedef S<>::type T;
+	public void testExplicitSpecializationOfTemplateDeclaredInHeader_401820() throws Exception {
+		IType T = getBindingFromASTName("T", 1);
+		assertEquals("int", ASTTypeUtil.getType(T));
+	}
 }
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPTemplateDefinition.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPTemplateDefinition.java
index 79f92c900bf..9aea40da2e9 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPTemplateDefinition.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPTemplateDefinition.java
@@ -114,8 +114,11 @@ public abstract class CPPTemplateDefinition extends PlatformObject implements IC
 		final ICPPClassTemplate ib = getIndexBinding();
 		if (ib instanceof ICPPInstanceCache) {
 			ICPPTemplateInstance cand= ((ICPPInstanceCache) ib).getInstance(arguments);
-			if (cand instanceof IIndexBinding && 
-					getTemplateName().getTranslationUnit().getIndexFileSet().containsDeclaration((IIndexBinding) cand)) {
+			if (cand instanceof IIndexBinding) {
+				if (getTemplateName().getTranslationUnit().getIndexFileSet().containsDeclaration((IIndexBinding) cand)) {
+					return cand;
+				}
+			} else {
 				return cand;
 			}
 		}