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 485a45f6707..889c9101972 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
@@ -461,7 +461,7 @@ public class CPPTemplates {
 			ICPPTemplateInstance result = ((ICPPInstanceCache) template).getInstance(args);
 			if (forDefinition && result instanceof IIndexBinding)
 				return null;
-			if (result != null) {
+			if (result != null && !result.isExplicitSpecialization()) {
 				// Don't use the cached instance if its argument is an index type and the requested
 				// argument is an AST type. Despite identical signatures the types may be different.
 				ICPPTemplateArgument[] instanceArgs = result.getTemplateArguments();