code: /*
  IllegalIdentifierName
  format = (default)(?i)^(?!(record|yield|var|permits|sealed|_)$).+$
  tokens = (default)CLASS_DEF, INTERFACE_DEF, ENUM_DEF, ANNOTATION_DEF, ANNOTATION_FIELD_DEF, \
           PARAMETER_DEF, VARIABLE_DEF, METHOD_DEF, ENUM_CONSTANT_DEF, PATTERN_VARIABLE_DEF, \
           RECORD_DEF, RECORD_COMPONENT_DEF, LAMBDA
  
  
  */
  
  //non-compiled with javac: Compilable with Java14
  package com.puppycrawl.tools.checkstyle.checks.naming.illegalidentifiername;
  
  import java.util.function.Function;
  
  public class InputIllegalIdentifierNameLambda {
  
      public static void main(String... args) {
          Function<String, String> f1 = var -> var; // violation
          Function<String, String> f2 = (var) -> var; // violation
          Function<String, String> f3 = myLambdaParam -> myLambdaParam; // ok
      }
  
      enum Day {
          MON,
          TUE,
          WED,
          THU,
          FRI,
          SAT,
          SUN,
          var, // violation
      }
  
      int yield(Day day) { // violation
          return switch (day) {
              case MON, TUE -> Math.addExact(0, 1);
              case WED -> Math.addExact(1, 1);
              case THU, SAT, FRI, SUN -> 0;
              case var -> 23; // ok, caught above in initialization
              default -> {
                  Function<String, String> f4 = var -> var; // violation
                  yield Math.addExact(2, 1); // ok, yield statement
              }
          };
      }
  }
  