diff --git a/clippy_lints/src/ptr.rs b/clippy_lints/src/ptr.rs
index 7b6bd69ffca..460d631fab0 100644
--- a/clippy_lints/src/ptr.rs
+++ b/clippy_lints/src/ptr.rs
@@ -145,7 +145,7 @@ impl<'tcx> LateLintPass<'tcx> for Ptr {
                     cx,
                     CMP_NULL,
                     expr.span,
-                    "Comparing with null is better expressed by the `.is_null()` method",
+                    "comparing with null is better expressed by the `.is_null()` method",
                 );
             }
         }
diff --git a/tests/ui/cmp_null.stderr b/tests/ui/cmp_null.stderr
index b563a2ebec2..a1f4c70fb27 100644
--- a/tests/ui/cmp_null.stderr
+++ b/tests/ui/cmp_null.stderr
@@ -1,4 +1,4 @@
-error: Comparing with null is better expressed by the `.is_null()` method
+error: comparing with null is better expressed by the `.is_null()` method
   --> $DIR/cmp_null.rs:9:8
    |
 LL |     if p == ptr::null() {
@@ -6,7 +6,7 @@ LL |     if p == ptr::null() {
    |
    = note: `-D clippy::cmp-null` implied by `-D warnings`
 
-error: Comparing with null is better expressed by the `.is_null()` method
+error: comparing with null is better expressed by the `.is_null()` method
   --> $DIR/cmp_null.rs:14:8
    |
 LL |     if m == ptr::null_mut() {