SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "main"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        WHITESPACE "\n   "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          IDENT_PAT
            NAME
              IDENT "foo"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          CLOSURE_EXPR
            PARAM_LIST
              PIPE "|"
              PARAM
                IDENT_PAT
                  NAME
                    IDENT "bar"
              COMMA ","
              WHITESPACE " "
              PARAM
                IDENT_PAT
                  NAME
                    IDENT "baz"
                COLON ":"
                WHITESPACE " "
                PATH_TYPE
                  PATH
                    PATH_SEGMENT
                      NAME_REF
                        IDENT "Baz"
              COMMA ","
              WHITESPACE " "
              PARAM
                IDENT_PAT
                  NAME
                    IDENT "qux"
                COLON ":"
                WHITESPACE " "
                PATH_TYPE
                  PATH
                    PATH
                      PATH_SEGMENT
                        NAME_REF
                          IDENT "Qux"
                    COLON2 "::"
                    PATH_SEGMENT
                      NAME_REF
                        IDENT "Quux"
              PIPE "|"
            WHITESPACE " "
            TUPLE_EXPR
              L_PAREN "("
              R_PAREN ")"
          SEMICOLON ";"
        WHITESPACE "\n"
        R_CURLY "}"
  WHITESPACE "\n"
