SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "foo"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        WHITESPACE " "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          WILDCARD_PAT
            UNDERSCORE "_"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          BLOCK_EXPR
            ASYNC_KW "async"
            WHITESPACE " "
            STMT_LIST
              L_CURLY "{"
              R_CURLY "}"
        WHITESPACE " "
        R_CURLY "}"
  WHITESPACE "\n"
error 27: expected SEMICOLON
