1 files changed, 20 insertions, 0 deletions
diff --git a/src/tools/clippy/src/docs/is_digit_ascii_radix.txt b/src/tools/clippy/src/docs/is_digit_ascii_radix.txt
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index 000000000..9f11cf430
--- /dev/null
+++ b/src/tools/clippy/src/docs/is_digit_ascii_radix.txt
@@ -0,0 +1,20 @@
+### What it does
+Finds usages of [`char::is_digit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_digit) that
+can be replaced with [`is_ascii_digit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_ascii_digit) or
+[`is_ascii_hexdigit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_ascii_hexdigit).
+
+### Why is this bad?
+`is_digit(..)` is slower and requires specifying the radix.
+
+### Example
+```
+let c: char = '6';
+c.is_digit(10);
+c.is_digit(16);
+```
+Use instead:
+```
+let c: char = '6';
+c.is_ascii_digit();
+c.is_ascii_hexdigit();
+```
+\ No newline at end of file