[1]: https://www.thunderbird.net/en-US/thunderbird/60.8.0/releasenotes/

       Compiling style_traits v0.0.1 (/dev/shm/bee-root/thunderbird/thunderbird-60.8.0-0/source/servo/components/style_traits)
    warning: use of deprecated item 'std::ascii::AsciiExt': use inherent methods instead
      --> servo/components/style_traits/viewport.rs:10:30
       |
    10 | #[allow(unused_imports)] use std::ascii::AsciiExt;
       |                              ^^^^^^^^^^^^^^^^^^^^
       |
       = note: #[warn(deprecated)] on by default
    error: missing documentation for macro
       --> servo/components/style_traits/values.rs:139:1
        |
    139 | macro_rules! serialize_function {
        | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        |
    note: lint level defined here
       --> servo/components/style_traits/lib.rs:12:22
        |
    12  | #![deny(unsafe_code, missing_docs)]
        |                      ^^^^^^^^^^^^

    error: missing documentation for macro
       --> servo/components/style_traits/values.rs:408:1
        |
    408 | macro_rules! define_css_keyword_enum {
        | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    error: aborting due to 2 previous errors

    error: Could not compile `style_traits`.

[1]: https://bugzilla.mozilla.org/show_bug.cgi?id=1519629