[cs] CPD: fix issue where semicolons following using directives were not filtered

pmd-cs/src/main/java/net/sourceforge/pmd/cpd/CsTokenizer.java

@@ -58,6 +58,7 @@ public class CsTokenizer extends AntlrTokenizer {
         private final boolean ignoreUsings;
         private boolean discardingUsings = false;
         private boolean discardingNL = false;
+        private boolean discardCurrent = false;
 
         CsTokenFilter(final AntlrTokenManager tokenManager, boolean ignoreUsings) {
             super(tokenManager);
@@ -71,6 +72,7 @@ public class CsTokenizer extends AntlrTokenizer {
 
         @Override
         protected void analyzeTokens(final AntlrToken currentToken, final Iterable<AntlrToken> remainingTokens) {
+            discardCurrent = false;
             skipUsingDirectives(currentToken, remainingTokens);
         }
 
@@ -78,8 +80,9 @@ public class CsTokenizer extends AntlrTokenizer {
             final int type = currentToken.getType();
             if (type == CSharpLexer.USING && isUsingDirective(remainingTokens)) {
                 discardingUsings = true;
-            } else if (type == CSharpLexer.SEMICOLON) {
+            } else if (type == CSharpLexer.SEMICOLON && discardingUsings) {
                 discardingUsings = false;
+                discardCurrent = true;
             }
         }
 
@@ -147,7 +150,7 @@ public class CsTokenizer extends AntlrTokenizer {
 
         @Override
         protected boolean isLanguageSpecificDiscarding() {
-            return discardingUsings || discardingNL;
+            return discardingUsings || discardingNL || discardCurrent;
         }
     }
 }