Use specialized EnumSet for TypeMatcher instead of generic HashSet. (#207)

Author: blackwinter

metafix/src/main/java/org/metafacture/metafix/Value.java

@@ -22,6 +22,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.ConcurrentModificationException;
+import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
@@ -304,7 +305,7 @@ enum Type {
 
     public static class TypeMatcher {
 
-        private final Set<Type> expected = new HashSet<>();
+        private final Set<Type> expected = EnumSet.noneOf(Type.class);
         private final Value value;
 
         private TypeMatcher(final Value value) {