我有以下功能:
-spec check_connection_header(list()) -> atom().
check_connection_header([{<<"Connection">>, <<"close">>}|_]) ->
close;
check_connection_header([{<<"Connection">>, <<"Close">>}|_]) ->
close;
check_connection_header([{<<"connection">>, <<"close">>}|_]) ->
close;
check_connection_header([{<<"connection">>, <<"Close">>}|_]) ->
close;
check_connection_header([_|Rest]) ->
check_connection_header(Rest);
check_connection_header([])->
keep_alive.
当我运行透析器时,我得到以下输出:
131: The pattern [{<<67:8/integer-unit:1,111:8/integer-unit:1,110:8/integer-unit:1,110:8/integer-unit:1,101:8/integer-unit:1,99:8/integer-unit:1,116:8/integer-unit:1,105:8/integer-unit:1,111:8/integer-unit:1,110:8/integer-unit:1>>, <<99:8/integer-unit:1,108:8/integer-unit:1,111:8/integer-unit:1,115:8/integer-unit:1,101:8/integer-unit:1>>} | _] can never match the type []
134: The pattern [{<<67:8/integer-unit:1,111:8/integer-unit:1,110:8/integer-unit:1,110:8/integer-unit:1,101:8/integer-unit:1,99:8/integer-unit:1,116:8/integer-unit:1,105:8/integer-unit:1,111:8/integer-unit:1,110:8/integer-unit:1>>, <<67:8/integer-unit:1,108:8/integer-unit:1,111:8/integer-unit:1,115:8/integer-unit:1,101:8/integer-unit:1>>} | _] can never match the type []
137: The pattern [{<<99:8/integer-unit:1,111:8/integer-unit:1,110:8/integer-unit:1,110:8/integer-unit:1,101:8/integer-unit:1,99:8/integer-unit:1,116:8/integer-unit:1,105:8/integer-unit:1,111:8/integer-unit:1,110:8/integer-unit:1>>, <<99:8/integer-unit:1,108:8/integer-unit:1,111:8/integer-unit:1,115:8/integer-unit:1,101:8/integer-unit:1>>} | _] can never match the type []
140: The pattern [{<<99:8/integer-unit:1,111:8/integer-unit:1,110:8/integer-unit:1,110:8/integer-unit:1,101:8/integer-unit:1,99:8/integer-unit:1,116:8/integer-unit:1,105:8/integer-unit:1,111:8/integer-unit:1,110:8/integer-unit:1>>, <<67:8/integer-unit:1,108:8/integer-unit:1,111:8/integer-unit:1,115:8/integer-unit:1,101:8/integer-unit:1>>} | _] can never match the type []
143: The pattern [_ | Rest] can never match the type []
我对透析器很陌生,无法解释透析器的输出。我明白这是说函数的前 5 个子句不能匹配 [],但这是我故意的,因为我匹配的是第六个子句中的空列表。
我的 erlang 版本是 Erlang/OTP 19.0,我的透析器版本是 v3.0。
一个有趣的发现是,当我在另一台机器上运行 dilyzer v2.8 和 Erlang/OTP 18 时,dialyzer 不会抱怨上述代码。
到目前为止我尝试过的事情:
我对 erlang 中的二进制文件不是很有经验,所以我最初的想法是我误解了二进制模式匹配,但事实似乎并非如此。该函数通过了我的测试用例(使用 [] 作为参数调用该函数没有问题),而且如果我在函数头中用普通字符串替换二进制文件,我也会得到透析器的相同投诉。
重建plt并清理项目
提前致谢