SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "foo"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        WHITESPACE "\n    "
        COMMENT "// reference operator"
        WHITESPACE "\n    "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          WILDCARD_PAT
            UNDERSCORE "_"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          REF_EXPR
            AMP "&"
            LITERAL
              INT_NUMBER "1"
          SEMICOLON ";"
        WHITESPACE "\n    "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          WILDCARD_PAT
            UNDERSCORE "_"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          REF_EXPR
            AMP "&"
            MUT_KW "mut"
            WHITESPACE " "
            REF_EXPR
              AMP "&"
              CALL_EXPR
                PATH_EXPR
                  PATH
                    PATH_SEGMENT
                      NAME_REF
                        IDENT "f"
                ARG_LIST
                  L_PAREN "("
                  R_PAREN ")"
          SEMICOLON ";"
        WHITESPACE "\n    "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          WILDCARD_PAT
            UNDERSCORE "_"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          REF_EXPR
            AMP "&"
            PATH_EXPR
              PATH
                PATH_SEGMENT
                  NAME_REF
                    IDENT "raw"
          SEMICOLON ";"
        WHITESPACE "\n    "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          WILDCARD_PAT
            UNDERSCORE "_"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          REF_EXPR
            AMP "&"
            FIELD_EXPR
              PATH_EXPR
                PATH
                  PATH_SEGMENT
                    NAME_REF
                      IDENT "raw"
              DOT "."
              NAME_REF
                INT_NUMBER "0"
          SEMICOLON ";"
        WHITESPACE "\n    "
        COMMENT "// raw reference operator"
        WHITESPACE "\n    "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          WILDCARD_PAT
            UNDERSCORE "_"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          REF_EXPR
            AMP "&"
            RAW_KW "raw"
            WHITESPACE " "
            MUT_KW "mut"
            WHITESPACE " "
            PATH_EXPR
              PATH
                PATH_SEGMENT
                  NAME_REF
                    IDENT "foo"
          SEMICOLON ";"
        WHITESPACE "\n    "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          WILDCARD_PAT
            UNDERSCORE "_"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          REF_EXPR
            AMP "&"
            RAW_KW "raw"
            WHITESPACE " "
            CONST_KW "const"
            WHITESPACE " "
            PATH_EXPR
              PATH
                PATH_SEGMENT
                  NAME_REF
                    IDENT "foo"
          SEMICOLON ";"
        WHITESPACE "\n"
        R_CURLY "}"
  WHITESPACE "\n"
