docs: public static <T extends StatementTree> Matcher<T> previousStatement(
        Matcher<StatementTree> matcher) {
      return (T statement, VisitorState state) -> {
        BlockTree block = state.findEnclosing(BlockTree.class);
        if (block == null) {
          return false;
        }
        List<? extends StatementTree> statements = block.getStatements();
        int idx = statements.indexOf(statement);
        if (idx <= 0) {
          // The block wrapping us doesn't contain this statement, or doesn't contain a previous
          // statement.
          return false;
        }
        return matcher.matches(statements.get(idx - 1), state);
      };
    }