diff --git a/src/Compiler/Input/Filter/ExcludeFileFilter.cs b/src/Compiler/Input/Filter/ExcludeFileFilter.cs
index d6742d38..442429ae 100644
--- a/src/Compiler/Input/Filter/ExcludeFileFilter.cs
+++ b/src/Compiler/Input/Filter/ExcludeFileFilter.cs
@@ -8,7 +8,7 @@ public ExcludeFileFilter(IEnumerable<string> fileNames) : base(fileNames)
         {
         }
         
-        public new bool Filter(string path)
+        public override bool Filter(string path)
         {
             return !base.Filter(path);
         }
diff --git a/src/Compiler/Input/Filter/IncludeFileFilter.cs b/src/Compiler/Input/Filter/IncludeFileFilter.cs
index 7121bf1f..6c1d4f2d 100644
--- a/src/Compiler/Input/Filter/IncludeFileFilter.cs
+++ b/src/Compiler/Input/Filter/IncludeFileFilter.cs
@@ -13,7 +13,7 @@ public IncludeFileFilter(IEnumerable<string> fileNames)
             FileNames = fileNames;
         }
 
-        public bool Filter(string path)
+        public virtual bool Filter(string path)
         {
             return FileNames.Contains(Path.GetFileName(path));
         }
diff --git a/tests/CompilerTest/Input/Filter/ExcludeFileFilterTest.cs b/tests/CompilerTest/Input/Filter/ExcludeFileFilterTest.cs
index 3766af01..342b80f5 100644
--- a/tests/CompilerTest/Input/Filter/ExcludeFileFilterTest.cs
+++ b/tests/CompilerTest/Input/Filter/ExcludeFileFilterTest.cs
@@ -28,5 +28,13 @@ public void ItDoesntFilterIfNotMatch()
                 filter.Filter("_TestData/abc/NotFoo.txt")
             );
         }
+        
+        [Fact]
+        public void ItOverridesBaseFilter()
+        {
+            Assert.False(
+                ((IFileFilter) filter).Filter("_TestData/abc/Foo.txt")
+            );
+        }
     }
 }