Fix sonarcloud issues

Author: C4tWithShell

community-rust-frontend/src/main/java/org/sonar/rust/RustGrammar.java

@@ -2056,12 +2056,15 @@ private static void identifiers(LexerlessGrammarBuilder b) {
   }
 
   private static String exceptKeywords() {
-    StringBuilder sb = new StringBuilder("(?<!(");
     String[] values = RustKeyword.keywordValues();
+    if (values.length == 0) {
+      return "";
+    }
+
+    StringBuilder sb = new StringBuilder("(?<!(");
     sb.append("^").append(values[0]).append("$");
-    for (String kw : values) {
-      sb.append("|^");
-      sb.append(kw).append("$");
+    for (int i = 1; i < values.length; i++) {
+      sb.append("|^").append(values[i]).append("$");
     }
     sb.append("))");
 

community-rust-frontend/src/test/java/org/sonar/rust/RustLexerTest.java

@@ -84,7 +84,7 @@ void testParsing() {
     assertThat(rootNode.getType()).isSameAs(RustGrammar.COMPILATION_UNIT);
     AstNode astNode = rootNode;
     // org.fest.assertions.Assertions.assertThat(astNode.getNumberOfChildren()).isEqualTo(4);
-    System.out.println(AstXmlPrinter.print(astNode));
+    // System.out.println(AstXmlPrinter.print(astNode));
 
   }
 
@@ -104,7 +104,8 @@ private void testImportParsing(String filename) {
     ParserAdapter<LexerlessGrammar> parser = new ParserAdapter<>(
         StandardCharsets.UTF_8, RustGrammar.create().build());
 
-    parser.parse(sexpr);
+    AstNode rootNode = parser.parse(sexpr);
+    assertThat(rootNode).isNotNull();
   }
 
   @Test
@@ -121,7 +122,8 @@ void testNumRange() {
     ParserAdapter<LexerlessGrammar> parser = new ParserAdapter<>(
         StandardCharsets.UTF_8, RustGrammar.create().build());
 
-    parser.parse(sexpr);
+    AstNode rootNode = parser.parse(sexpr);
+    assertThat(rootNode).isNotNull();
   }
 
   @Test
@@ -150,10 +152,6 @@ void testContinueProcessingCondition() {
 
     // Expect this to be parsed successfully or reproduce the issue
     AstNode rootNode = parser.parse(source);
-
-    // Debug output
-    System.out.println(AstXmlPrinter.print(rootNode));
-
     // Ensure parsing is successful
     assertThat(rootNode).isNotNull();
   }