From b280dbe5f73286a3f2a02e93c6c3e42181ec8aca Mon Sep 17 00:00:00 2001
From: Nadir Fejzic <nadirfejzo@gmail.com>
Date: Sat, 1 Oct 2022 16:50:45 +0200
Subject: [PATCH] docs: add docs for `unchecked_duration_subtraction` lint

---
 src/docs/unchecked_duration_subtraction.txt | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 src/docs/unchecked_duration_subtraction.txt

diff --git a/src/docs/unchecked_duration_subtraction.txt b/src/docs/unchecked_duration_subtraction.txt
new file mode 100644
index 00000000000..6b9c9308c87
--- /dev/null
+++ b/src/docs/unchecked_duration_subtraction.txt
@@ -0,0 +1,19 @@
+### What it does
+Finds patterns of unchecked subtraction of [`Duration`] from [`Instant::now()`].
+
+### Why is this bad?
+Unchecked subtraction could cause underflow on certain platforms, leading to bugs and/or
+unintentional panics.
+
+### Example
+```
+let time_passed = Instant::now() - Duration::from_secs(5);
+```
+
+Use instead:
+```
+let time_passed = Instant::now().checked_sub(Duration::from_secs(5));
+```
+
+[`Duration`]: std::time::Duration
+[`Instant::now()`]: std::time::Instant::now;
\ No newline at end of file