fix clippy::single_char_pattern perf findings

3 files changed, 3 insertions, 3 deletions

diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 5df8a4103b7..50a8f033672 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -1213,7 +1213,7 @@ pub fn get_cmd_lint_options(
             if lint_name == "help" {
                 describe_lints = true;
             } else {
-                lint_opts_with_position.push((arg_pos, lint_name.replace("-", "_"), level));
+                lint_opts_with_position.push((arg_pos, lint_name.replace('-', "_"), level));
             }
         }
     }
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index bd7b1639613..dc5f4ee0ece 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -335,7 +335,7 @@ fn build_options<O: Default>(
             Some((k, v)) => (k.to_string(), Some(v)),
         };
 
-        let option_to_lookup = key.replace("-", "_");
+        let option_to_lookup = key.replace('-', "_");
         match descrs.iter().find(|(name, ..)| *name == option_to_lookup) {
             Some((_, setter, type_desc, _)) => {
                 if !setter(&mut op, value) {
diff --git a/compiler/rustc_session/src/output.rs b/compiler/rustc_session/src/output.rs
index cc1e4bb198a..5689b723ad6 100644
--- a/compiler/rustc_session/src/output.rs
+++ b/compiler/rustc_session/src/output.rs
@@ -85,7 +85,7 @@ pub fn find_crate_name(sess: &Session, attrs: &[ast::Attribute], input: &Input)
                 );
                 sess.err(&msg);
             } else {
-                return validate(s.replace("-", "_"), None);
+                return validate(s.replace('-', "_"), None);
             }
         }
     }