## Special Unicode Productions
The following productions in the Rust grammar are defined in terms of Unicode
-properties: `ident`, `non_null`, `non_star`, `non_eol`, `non_slash_or_star`,
-`non_single_quote` and `non_double_quote`.
+properties: `ident`, `non_null`, `non_eol`, `non_single_quote` and `non_double_quote`.
### Identifiers
-The `ident` production is any nonempty Unicode string of the following form:
+The `ident` production is any nonempty Unicode[^non_ascii_idents] string of the following form:
+
+[^non_ascii_idents]: Non-ASCII characters in identifiers are currently feature
+ gated. This is expected to improve soon.
- The first character has property `XID_start`
- The remaining characters have property `XID_continue`
- `non_null` is any single Unicode character aside from `U+0000` (null)
- `non_eol` is `non_null` restricted to exclude `U+000A` (`'\n'`)
-- `non_star` is `non_null` restricted to exclude `U+002A` (`*`)
-- `non_slash_or_star` is `non_null` restricted to exclude `U+002F` (`/`) and `U+002A` (`*`)
- `non_single_quote` is `non_null` restricted to exclude `U+0027` (`'`)
- `non_double_quote` is `non_null` restricted to exclude `U+0022` (`"`)