Fixed Unused... checks don't work together (bug 805954)

docs/releasenotes.html

@@ -251,6 +251,8 @@
         <li class="body">Unused local variables are not always detected (bug 798111)</li>
 
 	<li class="body">Fixed allowThrowsTagsForSubclasses/allowMissingThrowsTag interfere (bug 803577) </li>
+	
+	    <li class="body">Unused... checks don't work together (bug 805954)</li>
 
       </ul>
 

src/checkstyle/com/puppycrawl/tools/checkstyle/checks/usage/AbstractUsageCheck.java

@@ -117,7 +117,7 @@ public abstract class AbstractUsageCheck
         catch (SymbolTableException ste) {
             logError(ste);
         }
-        ASTManager.getInstance().clear();
+        ASTManager.getInstance().removeCheck(this);
     }
 
     /**

src/checkstyle/com/puppycrawl/tools/checkstyle/checks/usage/transmogrify/ASTManager.java

@@ -197,13 +197,18 @@ public final class ASTManager
     }
 
     /**
-     * Clears all managed elements.
+     * Removes a check and its check nodes. Clears all managed elements if
+     * last check removed.
+     * @param check
      */
-    public void clear()
+    public void removeCheck(AbstractUsageCheck aCheck)
     {
-        mCheckNodes.clear();
-        mCompleteTree = null;
-        mMap.clear();
-        mTrees.clear();
+        mCheckNodes.remove(aCheck);
+        if (mCheckNodes.isEmpty()) {
+            mCompleteTree = null;
+            mMap.clear();
+            mTrees.clear();
+        }
+        
     }
 }