The generated page HTML contains a <div> tag in the header, which is not valid as per the HTML spec (which only allows "Metadata content"). This has been the case since #106915, which moved this div from the body to the header.
I believe browsers will open the body if an invalid tag is encountered in the header (which you can see in inspect elements, where every item in between </div> </head> are inside of <body>), or something like that.
This causes at least one bug: the #![doc(html_favicon_url = "...")] attribute, which expands into a <link rel="icon" href="...">, is not displayed on Chrome and Chromium-based browsers.
You can see this in the time crate on docs.rs:
- Chrome
- Firefox
Generated HTML:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<!-- ... -->
<div id="rustdoc-vars"
<!-- ... -->
<link rel="icon" href="https://avatars0.githubusercontent.com/u/55999857">
<!-- ... -->
</head>vs inspect element:
<html lang="en" data-theme="light">
<head>
<meta charset="utf-8">
<!-- ... -->
</head>
<div style="display: none; position: fixed; width: 100%; height: 100%; z-index: 1;"></div>
<body class="rustdoc-page">
<div id="rustdoc-vars"
<!-- ... -->
<link rel="icon" href="https://avatars0.githubusercontent.com/u/55999857">
<!-- ... -->
</body>Manually moving the link tag to the header correctly displays the favicon:
2. 
The generated page HTML contains a
<div>tag in the header, which is not valid as per the HTML spec (which only allows "Metadata content"). This has been the case since #106915, which moved this div from the body to the header.I believe browsers will open the body if an invalid tag is encountered in the header (which you can see in inspect elements, where every item in between
</div></head>are inside of<body>), or something like that.This causes at least one bug: the
#![doc(html_favicon_url = "...")]attribute, which expands into a<link rel="icon" href="...">, is not displayed on Chrome and Chromium-based browsers.You can see this in the
timecrate on docs.rs:Generated HTML:
vs inspect element:
Manually moving the
linktag to the header correctly displays the favicon:2.