SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "foo"
    PARAM_LIST
      L_PAREN "("
      PARAM
        IDENT_PAT
          NAME
            IDENT "x"
        COLON ":"
        WHITESPACE " "
        PATH_TYPE
          PATH
            PATH_SEGMENT
              NAME_REF
                IDENT "i32"
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        R_CURLY "}"
  WHITESPACE "\n\n"
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "main"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        WHITESPACE "\n    "
        EXPR_STMT
          CALL_EXPR
            PATH_EXPR
              PATH
                PATH_SEGMENT
                  NAME_REF
                    IDENT "foo"
            ARG_LIST
              L_PAREN "("
              LOOP_EXPR
                LOOP_KW "loop"
                WHITESPACE " "
                BLOCK_EXPR
                  STMT_LIST
                    L_CURLY "{"
                    R_CURLY "}"
              R_PAREN ")"
          SEMICOLON ";"
        WHITESPACE "\n"
        R_CURLY "}"