diff --git a/tests/ui/single_char_pattern.fixed b/tests/ui/single_char_pattern.fixed
index 220b855ead5..2dd21790389 100644
--- a/tests/ui/single_char_pattern.fixed
+++ b/tests/ui/single_char_pattern.fixed
@@ -1,5 +1,7 @@
 // run-rustfix
 
+#![allow(unused_must_use)]
+
 use std::collections::HashSet;
 
 fn main() {
diff --git a/tests/ui/single_char_pattern.rs b/tests/ui/single_char_pattern.rs
index 9650eb2af32..dc2f9fe4959 100644
--- a/tests/ui/single_char_pattern.rs
+++ b/tests/ui/single_char_pattern.rs
@@ -1,5 +1,7 @@
 // run-rustfix
 
+#![allow(unused_must_use)]
+
 use std::collections::HashSet;
 
 fn main() {
diff --git a/tests/ui/single_char_pattern.stderr b/tests/ui/single_char_pattern.stderr
index 82ef00bfee8..0fcb203dbc1 100644
--- a/tests/ui/single_char_pattern.stderr
+++ b/tests/ui/single_char_pattern.stderr
@@ -1,5 +1,5 @@
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:7:13
+  --> $DIR/single_char_pattern.rs:9:13
    |
 LL |     x.split("x");
    |             ^^^ help: try using a char instead: `'x'`
@@ -7,115 +7,115 @@ LL |     x.split("x");
    = note: `-D clippy::single-char-pattern` implied by `-D warnings`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:24:16
+  --> $DIR/single_char_pattern.rs:26:16
    |
 LL |     x.contains("x");
    |                ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:25:19
+  --> $DIR/single_char_pattern.rs:27:19
    |
 LL |     x.starts_with("x");
    |                   ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:26:17
+  --> $DIR/single_char_pattern.rs:28:17
    |
 LL |     x.ends_with("x");
    |                 ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:27:12
+  --> $DIR/single_char_pattern.rs:29:12
    |
 LL |     x.find("x");
    |            ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:28:13
+  --> $DIR/single_char_pattern.rs:30:13
    |
 LL |     x.rfind("x");
    |             ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:29:14
+  --> $DIR/single_char_pattern.rs:31:14
    |
 LL |     x.rsplit("x");
    |              ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:30:24
+  --> $DIR/single_char_pattern.rs:32:24
    |
 LL |     x.split_terminator("x");
    |                        ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:31:25
+  --> $DIR/single_char_pattern.rs:33:25
    |
 LL |     x.rsplit_terminator("x");
    |                         ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:32:17
+  --> $DIR/single_char_pattern.rs:34:17
    |
 LL |     x.splitn(0, "x");
    |                 ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:33:18
+  --> $DIR/single_char_pattern.rs:35:18
    |
 LL |     x.rsplitn(0, "x");
    |                  ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:34:15
+  --> $DIR/single_char_pattern.rs:36:15
    |
 LL |     x.matches("x");
    |               ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:35:16
+  --> $DIR/single_char_pattern.rs:37:16
    |
 LL |     x.rmatches("x");
    |                ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:36:21
+  --> $DIR/single_char_pattern.rs:38:21
    |
 LL |     x.match_indices("x");
    |                     ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:37:22
+  --> $DIR/single_char_pattern.rs:39:22
    |
 LL |     x.rmatch_indices("x");
    |                      ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:38:26
+  --> $DIR/single_char_pattern.rs:40:26
    |
 LL |     x.trim_start_matches("x");
    |                          ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:39:24
+  --> $DIR/single_char_pattern.rs:41:24
    |
 LL |     x.trim_end_matches("x");
    |                        ^^^ help: try using a char instead: `'x'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:41:13
+  --> $DIR/single_char_pattern.rs:43:13
    |
 LL |     x.split("/n");
    |             ^^^^ help: try using a char instead: `'/n'`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:46:31
+  --> $DIR/single_char_pattern.rs:48:31
    |
 LL |     x.replace(";", ",").split(","); // issue #2978
    |                               ^^^ help: try using a char instead: `','`
 
 error: single-character string constant used as pattern
-  --> $DIR/single_char_pattern.rs:47:19
+  --> $DIR/single_char_pattern.rs:49:19
    |
 LL |     x.starts_with("/x03"); // issue #2996
    |                   ^^^^^^ help: try using a char instead: `'/x03'`