diff --git a/ICSharpCode.Decompiler.Tests/TestCases/Pretty/DelegateConstruction.cs b/ICSharpCode.Decompiler.Tests/TestCases/Pretty/DelegateConstruction.cs
index 80998f6fa..86ec9d1cc 100644
--- a/ICSharpCode.Decompiler.Tests/TestCases/Pretty/DelegateConstruction.cs
+++ b/ICSharpCode.Decompiler.Tests/TestCases/Pretty/DelegateConstruction.cs
@@ -392,17 +392,31 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 			return () => integerData;
 		}
 
+#if !MCS
+		// does not compile with mcs...
 		public static Func<int> Issue1773b(object data)
 		{
+#if ROSLYN
 			dynamic dynamicData = data;
 			return () => dynamicData.DynamicCall();
+#else
+			// This is a bug in the old csc: captured dynamic local variables did not have the [DynamicAttribute]
+			// on the display-class field.
+			return () => ((dynamic)data).DynamicCall();
+#endif
 		}
 
 		public static Func<int> Issue1773c(object data)
 		{
+#if ROSLYN
 			dynamic dynamicData = data;
 			return () => dynamicData;
+#else
+			return () => (dynamic)data;
+#endif
 		}
+#endif
+
 #if ROSLYN
 		public static Func<string> Issue1773d((int Integer, string String) data)
 		{