Add tests for bitwise operations

Author: rail-rain

tests/ui/manual_memcpy.rs

@@ -167,6 +167,14 @@ pub fn manual_copy_with_counters(src: &[i32], dst: &mut [i32], dst2: &mut [i32])
         count += 1;
         count += 1;
     }
+
+    // make sure parentheses are added properly to bitwise operators, which have lower precedence than
+    // arithmetric ones
+    let mut count = 0 << 1;
+    for i in 0..1 << 1 {
+        dst[count] = src[i + 2];
+        count += 1;
+    }
 }
 
 #[warn(clippy::needless_range_loop, clippy::manual_memcpy)]

tests/ui/manual_memcpy.stderr

@@ -135,8 +135,14 @@ LL |     dst2[30..(src.len() + 30)].clone_from_slice(&src[..]) {
 error: it looks like you're manually copying between slices
   --> $DIR/manual_memcpy.rs:174:14
    |
+LL |     for i in 0..1 << 1 {
+   |              ^^^^^^^^^ help: try replacing the loop by: `dst[(0 << 1)..((1 << 1) + (0 << 1))].clone_from_slice(&src[2..((1 << 1) + 2)])`
+
+error: it looks like you're manually copying between slices
+  --> $DIR/manual_memcpy.rs:182:14
+   |
 LL |     for i in 0..src.len() {
    |              ^^^^^^^^^^^^ help: try replacing the loop by: `dst[..src.len()].clone_from_slice(&src[..])`
 
-error: aborting due to 21 previous errors
+error: aborting due to 22 previous errors