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 eae38c57ac0..f38ec70b8ba 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
@@ -11348,6 +11348,17 @@ public class AST2CPPTests extends AST2CPPTestBase {
 		assertSameType((ITypedef) helper.assertNonProblem("loong_type"), CPPBasicType.LONG);
 	}
 
+	//	template <typename T>
+	//	struct underlying_type {
+	//		using type = __underlying_type(T);
+	//	};
+	//	enum class E : short {};
+	//	using target = underlying_type<E>::type;
+	public void testUnderlyingType_548954() throws Exception {
+		BindingAssertionHelper helper = getAssertionHelper();
+		assertSameType((ITypedef) helper.assertNonProblem("target"), CPPBasicType.SHORT);
+	}
+
 	//	template <typename T>
 	//	struct underlying_type {
 	//	    typedef __underlying_type(T) type;
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/AbstractGNUSourceCodeParser.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/AbstractGNUSourceCodeParser.java
index 7b9d8ba7562..f5aaab64105 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/AbstractGNUSourceCodeParser.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/AbstractGNUSourceCodeParser.java
@@ -2780,6 +2780,7 @@ public abstract class AbstractGNUSourceCodeParser implements ISourceCodeParser {
 			// gcc-special
 		case IGCCToken.t_typeof:
 		case IGCCToken.t__attribute__:
+		case IGCCToken.tTT_underlying_type:
 
 			// content assist
 		case IToken.tCOMPLETION: