The following tests are added in DeduplicationTest demonstrate the problem:

        // generates typeSwitch
        group((Function<Object, Integer>) x -> switch (x) { case String s -> s.length(); default -> -1; },
              (Function<Object, Integer>) x -> switch (x) { case String s -> s.length(); default -> -1; });

        // local variable names are erroneously significant
        group((Function<Object, Integer>) x -> {
                    int y1 = -1;
                    return y1;
                },
              (Function<Object, Integer>) x -> {
                    int y2 = -1;
                    return y2;
               });

        // consequently, instanceof that generates names with "tmp" + variableIndex++ + "$" demonstrate the problem again
        group((Function<Object, Integer>) x -> x instanceof int i2 ? i2 : -1,
                  (Function<Object, Integer>) x -> x instanceof int i2 ? i2 : -1);