Fix NullPointerException in VariableSymbolComputer.visitLValue by adding null check

Co-authored-by: nixel2007 <1132840+nixel2007@users.noreply.github.com>

Author: Copilot

src/main/java/com/github/_1c_syntax/bsl/languageserver/context/computer/VariableSymbolComputer.java

@@ -165,6 +165,7 @@ public ParseTree visitParam(BSLParser.ParamContext ctx) {
   public ParseTree visitLValue(BSLParser.LValueContext ctx) {
     if (
       ctx.getChildCount() > 1
+      || ctx.IDENTIFIER() == null
       || currentMethodVariables.containsKey(ctx.getText())
       || moduleVariables.containsKey(ctx.getText())
     ) {

src/test/java/com/github/_1c_syntax/bsl/languageserver/context/computer/VariableSymbolTest.java

@@ -148,4 +148,23 @@ void testVariableKind() {
 
   }
 
+  @Test
+  void testNoNPEOnMalformedLValue() {
+    // Test for issue BSL-LANGUAGE-SERVER-G5
+    // Malformed code with syntax errors should not cause NPE
+    String code = """
+      Процедура Тест()
+        Переменная = 
+        =
+        Док.Записать
+      КонецПроцедуры
+      """;
+    
+    var ctx = TestUtils.getDocumentContext(code);
+    var variables = ctx.getSymbolTree().getVariables();
+    
+    // Should not throw NullPointerException
+    assertThat(variables).isNotNull();
+  }
+
 }