{"id":4281,"date":"2026-06-17T07:00:00","date_gmt":"2026-06-16T22:00:00","guid":{"rendered":"https:\/\/litcoder.com\/?p=4281"},"modified":"2026-05-24T12:48:17","modified_gmt":"2026-05-24T03:48:17","slug":"rust-comparison-is-useless-due-to-type-limits","status":"publish","type":"post","link":"https:\/\/litcoder.com\/?p=4281","title":{"rendered":"Rust: comparison is useless due to type limits"},"content":{"rendered":"\n<p class=\"has-text-align-center wp-block-paragraph\">&#8220;<em>\ud0c0\uc785 \uc81c\ud55c \ub54c\ubb38\uc5d0 \uc774 \ube44\uad50\uc5f0\uc0b0\uc740 \uc4f8.\ubaa8.\uc5c6.\ub2e4.<\/em>&#8220;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">IndexSet\uc774 \ud558\ub098 \uc788\ub2e4\uace0 \ud560 \ub54c, \uadf8 \uc548\uc5d0 \ud558\ub098\ub77c\ub3c4 \uc544\uc774\ud15c\uc774 \uc788\uc73c\uba74 true\ub97c \ubc18\ud658\ud558\uace0 \uc544\ub2c8\uba74 false\ub97c \ubc18\ud658\ud558\ub294 \ub2e4\uc74c\uacfc \uac19\uc740 Rust code\ub97c \uc0dd\uac01\ud574 \ubcf4\uc790.<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"rust\" data-enlighter-theme=\"enlighter\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"true\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">use indexmap::IndexSet;\n\nfn has_item(item_set: &amp;IndexSet&lt;String>) -> bool {\n    item_set.iter().count() >= 0\n}<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\uac04\ub2e8\ud558\uac8c unittest\uc5d0 \ub123\uc5b4\uc11c \uc0c8\ub85c \uc0dd\uc131\ud574\uc11c \uc544\ubb34 \uc6d0\uc18c\ub3c4 \uc5c6\ub294 IndexSet\uc744 \ud558\ub098 \ub9cc\ub4e4\uc5b4\uc11c \ud655\uc778\ud558\ub294 test\ub97c \ub3cc\ub824\ubcf4\uba74<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"rust\" data-enlighter-theme=\"enlighter\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"true\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">#[cfg(test)]\nmod iset_test {\n    use super::*;\n\n    #[test]\n    fn test_item_exist() {\n        let idxset = IndexSet::&lt;String>::new();\n\n        \/\/ IndexSet \uc0dd\uc131\uc9c1\ud6c4\uc5d0\ub294 \uc544\uc774\ud15c\uc774 \uc5c6\uc5b4\uc57c \ud568.\n        assert_eq!(false, has_item(&amp;idxset));\n    }\n}\n<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\ud14c\uc2a4\ud2b8\uc5d0 \uc2e4\ud328 \ud558\ub294\ub370 \uc774\uc640 \ud568\uaed8 <strong>&#8220;comparison is useless due to type limits&#8221;<\/strong>\uc774\ub77c\ub294 \uacbd\uace0\uac00 \ucd9c\ub825\ub41c\ub2e4.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"494\" height=\"245\" src=\"https:\/\/litcoder.com\/wp-content\/uploads\/2026\/05\/rust_unused_comparisons.png\" alt=\"\" class=\"wp-image-4390\" style=\"width:500px\" srcset=\"https:\/\/litcoder.com\/wp-content\/uploads\/2026\/05\/rust_unused_comparisons.png 494w, https:\/\/litcoder.com\/wp-content\/uploads\/2026\/05\/rust_unused_comparisons-300x149.png 300w\" sizes=\"auto, (max-width: 494px) 100vw, 494px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">\uc774\uac83\uc740 <code>count()<\/code>\uac00 <code>usize<\/code> type\uc744 \ubc18\ud658\ud558\ub294\ub370 \ubd80\ud638 \uc5c6\ub294 \ud06c\uae30\ub97c \ub098\ud0c0\ub0b4\ub294 \uc774 \uac12\uc774 \uc74c\uc218 \uc77c \uc218\ub294 \uc5c6\uace0 \ud45c\ud604\ud560 \uc218 \uc788\ub294 \uac00\uc7a5 \uc791\uc740 \uc218\uac00 0\uc774\uae30 \ub54c\ubb38\uc5d0, 0\ubcf4\ub2e4 \uac19\uac70\ub098 \ud070\uc9c0 \ube44\uad50\ud558\ub294 \uad6c\ubb38\uc740 \ubb54\uac00 \uc798\ubabb\ub41c\uac8c \uc544\ub2c8\ub0d0\ub294 \uacbd\uace0\uc774\ub2e4.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\ud574\uacb0(?)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\uc0ac\uc2e4 \uc774 \ucf54\ub4dc\ub294 \ucc98\uc74c\ubd80\ud130 \uc798\ubabb \ub418\uc5c8\ub2e4. \uc544\uc774\ud15c\uc758 \uac2f\uc218\uac00 0\uac1c\uc778 \uacbd\uc6b0\ub3c4 \uc544\uc774\ud15c\uc774 \uc788\ub2e4\uace0 \ud310\ub2e8\ud558\ub294 \uac83\uc774\ub2c8\uae4c \ub9d0\uc774\ub2e4. \uc774 \uacbd\uace0\ub294 <code>count() &gt; 0<\/code>\uc73c\ub85c \ucf54\ub4dc\ub97c \ubcc0\uacbd\ud558\uac70\ub098 <code>is_empty()<\/code>\ub97c \ud1b5\ud574\uc11c \ubcf4\ub2e4 \uba85\uc2dc\uc801\uc73c\ub85c \uad6c\ud604\ud574\uc57c \ud55c\ub2e4. <\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"rust\" data-enlighter-theme=\"enlighter\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"true\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">fn has_item(item_set: &amp;IndexSet&lt;String>) -> bool {\n    \/\/item_set.iter().count() > 0\n    !item_set.is_empty()\n}<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\ub2e4\ub978 \uc5b8\uc5b4\uc758 \ucef4\ud30c\uc77c\ub7ec\ub4e4 \ucc98\ub7fc \ud0c0\uc785\uc774 \ub2e4\ub974\ub2e4\ub294 \uacbd\uace0\uc600\ub2e4\uac70\ub098 \uc870\uc6a9\ud588\ub2e4\uba74 \uadf8\ub0e5 \ubb34\uc2dc\ud558\uace0 \ub7f0\ud0c0\uc784 \ubc84\uadf8\ub85c \ub0a8\uc744 \uc218\ub3c4 \uc788\uc5c8\ub294\ub370, \uacbd\uace0 \ubb38\uad6c\uac00 \uc6cc\ub099 \uac15\ub825\ud558\ub2e4 \ubcf4\ub2c8 \ub355\ubd84\uc5d0 \ubbf8\ub9ac \ub514\ubc84\uae45\uc744 \ud560 \uc218 \uc788\ub294 \ubd80\uc218\ud6a8\uacfc\uc600\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>&#8220;\ud0c0\uc785 \uc81c\ud55c \ub54c\ubb38\uc5d0 \uc774 \ube44\uad50\uc5f0\uc0b0\uc740 \uc4f8.\ubaa8.\uc5c6.\ub2e4.&#8220; IndexSet\uc774 \ud558\ub098 \uc788\ub2e4\uace0 \ud560 \ub54c, \uadf8 \uc548\uc5d0 \ud558\ub098\ub77c\ub3c4 \uc544\uc774\ud15c\uc774 \uc788\uc73c\uba74 true\ub97c \ubc18\ud658\ud558\uace0 \uc544\ub2c8\uba74 false\ub97c \ubc18\ud658\ud558\ub294 \ub2e4\uc74c\uacfc \uac19\uc740 Rust code\ub97c \uc0dd\uac01\ud574 \ubcf4\uc790. \uac04\ub2e8\ud558\uac8c unittest\uc5d0 \ub123\uc5b4\uc11c \uc0c8\ub85c \uc0dd\uc131\ud574\uc11c \uc544\ubb34 \uc6d0\uc18c\ub3c4 \uc5c6\ub294 IndexSet\uc744 \ud558\ub098 \ub9cc\ub4e4\uc5b4\uc11c \ud655\uc778\ud558\ub294 test\ub97c \ub3cc\ub824\ubcf4\uba74 \ud14c\uc2a4\ud2b8\uc5d0 \uc2e4\ud328 \ud558\ub294\ub370 \uc774\uc640 \ud568\uaed8 &#8220;comparison is useless due to type limits&#8221;\uc774\ub77c\ub294 \uacbd\uace0\uac00 \ucd9c\ub825\ub41c\ub2e4. [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[5],"tags":[444,423],"class_list":["post-4281","post","type-post","status-publish","format-standard","hentry","category-programming","tag-indexset","tag-rust"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/posts\/4281","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/litcoder.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4281"}],"version-history":[{"count":18,"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/posts\/4281\/revisions"}],"predecessor-version":[{"id":4546,"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/posts\/4281\/revisions\/4546"}],"wp:attachment":[{"href":"https:\/\/litcoder.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4281"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/litcoder.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4281"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/litcoder.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4281"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}