diff --git a/src/wutil/wcstod.rs b/src/wutil/wcstod.rs
index 2ce71026f..b53134ae4 100644
--- a/src/wutil/wcstod.rs
+++ b/src/wutil/wcstod.rs
@@ -237,7 +237,7 @@ pub fn wcstod_underscores<Chars>(s: Chars, consumed: &mut usize) -> Result<f64,
         }
 
         // Look for characters leading "infinity" or "nan", case-insensitive.
-        if inf_nan_chars.next().map_or(false, |c| "iInN".contains(c)) {
+        if matches!(inf_nan_chars.next(), Some('i' | 'I' | 'n' | 'N')) {
             // We think it's inf or nan, so use the parser without underscores.
             // Note that leading underscores will now trigger an error.
             let f = wcstod_inner(chars, '.', consumed)?;