diff --git a/clippy_dev/src/update_lints.rs b/clippy_dev/src/update_lints.rs
index 10d859988f6f..23f58bc4915f 100644
--- a/clippy_dev/src/update_lints.rs
+++ b/clippy_dev/src/update_lints.rs
@@ -619,8 +619,8 @@ mod tests {
             Lint::new("should_assert_eq2", "group2", "abc", None, "module_name"),
         ];
         let expected = vec![
-            format!("[`should_assert_eq`]: {}#should_assert_eq", DOCS_LINK.to_string()),
-            format!("[`should_assert_eq2`]: {}#should_assert_eq2", DOCS_LINK.to_string()),
+            format!("[`should_assert_eq`]: {}#should_assert_eq", DOCS_LINK),
+            format!("[`should_assert_eq2`]: {}#should_assert_eq2", DOCS_LINK),
         ];
         assert_eq!(expected, gen_changelog_lint_list(lints.iter()));
     }
diff --git a/clippy_lints/src/if_then_panic.rs b/clippy_lints/src/if_then_panic.rs
index 10bca59e6d06..e8cea5529e88 100644
--- a/clippy_lints/src/if_then_panic.rs
+++ b/clippy_lints/src/if_then_panic.rs
@@ -78,10 +78,10 @@ impl LateLintPass<'_> for IfThenPanic {
                     if let Expr{kind: ExprKind::Unary(UnOp::Not, not_expr), ..} = e {
                          sugg::Sugg::hir_with_applicability(cx, not_expr, "..", &mut applicability).maybe_par().to_string()
                     } else {
-                       format!("!{}", sugg::Sugg::hir_with_applicability(cx, e, "..", &mut applicability).maybe_par().to_string())
+                       format!("!{}", sugg::Sugg::hir_with_applicability(cx, e, "..", &mut applicability).maybe_par())
                     }
                 } else {
-                   format!("!{}", sugg::Sugg::hir_with_applicability(cx, cond, "..", &mut applicability).maybe_par().to_string())
+                   format!("!{}", sugg::Sugg::hir_with_applicability(cx, cond, "..", &mut applicability).maybe_par())
                 };
 
                 span_lint_and_sugg(
diff --git a/clippy_lints/src/inherent_to_string.rs b/clippy_lints/src/inherent_to_string.rs
index 3c40ca50a098..61dd0eb4af7e 100644
--- a/clippy_lints/src/inherent_to_string.rs
+++ b/clippy_lints/src/inherent_to_string.rs
@@ -138,10 +138,10 @@ fn show_lint(cx: &LateContext<'_>, item: &ImplItem<'_>) {
             item.span,
             &format!(
                 "type `{}` implements inherent method `to_string(&self) -> String` which shadows the implementation of `Display`",
-                self_type.to_string()
+                self_type
             ),
             None,
-            &format!("remove the inherent method from type `{}`", self_type.to_string()),
+            &format!("remove the inherent method from type `{}`", self_type),
         );
     } else {
         span_lint_and_help(
@@ -150,10 +150,10 @@ fn show_lint(cx: &LateContext<'_>, item: &ImplItem<'_>) {
             item.span,
             &format!(
                 "implementation of inherent method `to_string(&self) -> String` for type `{}`",
-                self_type.to_string()
+                self_type
             ),
             None,
-            &format!("implement trait `Display` for type `{}` instead", self_type.to_string()),
+            &format!("implement trait `Display` for type `{}` instead", self_type),
         );
     }
 }
diff --git a/clippy_lints/src/suspicious_operation_groupings.rs b/clippy_lints/src/suspicious_operation_groupings.rs
index 44d5ff0b63ad..201aa0678240 100644
--- a/clippy_lints/src/suspicious_operation_groupings.rs
+++ b/clippy_lints/src/suspicious_operation_groupings.rs
@@ -678,7 +678,7 @@ fn suggestion_with_swapped_ident(
         Some(format!(
             "{}{}{}",
             snippet_with_applicability(cx, expr.span.with_hi(current_ident.span.lo()), "..", applicability),
-            new_ident.to_string(),
+            new_ident,
             snippet_with_applicability(cx, expr.span.with_lo(current_ident.span.hi()), "..", applicability),
         ))
     })
diff --git a/clippy_lints/src/transmute/transmute_int_to_char.rs b/clippy_lints/src/transmute/transmute_int_to_char.rs
index 8f884e6a4a17..e83d2e06b9a8 100644
--- a/clippy_lints/src/transmute/transmute_int_to_char.rs
+++ b/clippy_lints/src/transmute/transmute_int_to_char.rs
@@ -33,7 +33,7 @@ pub(super) fn check<'tcx>(
                     diag.span_suggestion(
                         e.span,
                         "consider using",
-                        format!("std::char::from_u32({}).unwrap()", arg.to_string()),
+                        format!("std::char::from_u32({}).unwrap()", arg),
                         Applicability::Unspecified,
                     );
                 },
diff --git a/clippy_lints/src/transmute/transmute_int_to_float.rs b/clippy_lints/src/transmute/transmute_int_to_float.rs
index 2b6a4cff81eb..05eee380d6f4 100644
--- a/clippy_lints/src/transmute/transmute_int_to_float.rs
+++ b/clippy_lints/src/transmute/transmute_int_to_float.rs
@@ -36,7 +36,7 @@ pub(super) fn check<'tcx>(
                     diag.span_suggestion(
                         e.span,
                         "consider using",
-                        format!("{}::from_bits({})", to_ty, arg.to_string()),
+                        format!("{}::from_bits({})", to_ty, arg),
                         Applicability::Unspecified,
                     );
                 },
diff --git a/clippy_lints/src/transmute/transmute_num_to_bytes.rs b/clippy_lints/src/transmute/transmute_num_to_bytes.rs
index dd5ded1c91a1..5ba58a764940 100644
--- a/clippy_lints/src/transmute/transmute_num_to_bytes.rs
+++ b/clippy_lints/src/transmute/transmute_num_to_bytes.rs
@@ -37,7 +37,7 @@ pub(super) fn check<'tcx>(
                     diag.span_suggestion(
                         e.span,
                         "consider using `to_ne_bytes()`",
-                        format!("{}.to_ne_bytes()", arg.to_string()),
+                        format!("{}.to_ne_bytes()", arg),
                         Applicability::Unspecified,
                     );
                 },