Interesting: Security advisory for rustc (CVE-2021-42574).

As an example, the following snippet (with {U+NNNN} replaced with the Unicode codepoint NNNN):

if access_level != "user{U+202E} {U+2066}// Check if admin{U+2069} {U+2066}" {

...would be rendered by bidirectional-aware tools as:

if access_level != "user" { // Check if admin