1 files changed, 26 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/bytecount.rs b/src/tools/clippy/tests/ui/bytecount.rs
new file mode 100644
index 000000000..d3ad26921
--- /dev/null
+++ b/src/tools/clippy/tests/ui/bytecount.rs
@@ -0,0 +1,26 @@
+#![allow(clippy::needless_borrow)]
+
+#[deny(clippy::naive_bytecount)]
+fn main() {
+    let x = vec![0_u8; 16];
+
+    let _ = x.iter().filter(|&&a| a == 0).count(); // naive byte count
+
+    let _ = (&x[..]).iter().filter(|&a| *a == 0).count(); // naive byte count
+
+    let _ = x.iter().filter(|a| **a > 0).count(); // not an equality count, OK.
+
+    let _ = x.iter().map(|a| a + 1).filter(|&a| a < 15).count(); // not a slice
+
+    let b = 0;
+
+    let _ = x.iter().filter(|_| b > 0).count(); // woah there
+
+    let _ = x.iter().filter(|_a| b == b + 1).count(); // nothing to see here, move along
+
+    let _ = x.iter().filter(|a| b + 1 == **a).count(); // naive byte count
+
+    let y = vec![0_u16; 3];
+
+    let _ = y.iter().filter(|&&a| a == 0).count(); // naive count, but not bytes
+}