From de2abc29e9f890433bef39eac46a84bdb9eaecf7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Matthias=20Kr=C3=BCger?= <matthias.krueger@famsik.de>
Date: Thu, 3 Feb 2022 21:44:47 +0100
Subject: [PATCH] clippy::perf fixes

single_char_pattern and to_string_in_format_args
---
 compiler/rustc_codegen_llvm/src/back/archive.rs | 2 +-
 compiler/rustc_interface/src/interface.rs       | 2 +-
 compiler/rustc_parse/src/parser/expr.rs         | 6 +++---
 compiler/rustc_typeck/src/check/expr.rs         | 8 ++++----
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/compiler/rustc_codegen_llvm/src/back/archive.rs b/compiler/rustc_codegen_llvm/src/back/archive.rs
index 5703a72c686..8a1dea4d99b 100644
--- a/compiler/rustc_codegen_llvm/src/back/archive.rs
+++ b/compiler/rustc_codegen_llvm/src/back/archive.rs
@@ -219,7 +219,7 @@ impl<'a> ArchiveBuilder<'a> for LlvmArchiveBuilder<'a> {
 
             match result {
                 Err(e) => {
-                    self.config.sess.fatal(&format!("Error calling dlltool: {}", e.to_string()));
+                    self.config.sess.fatal(&format!("Error calling dlltool: {}", e));
                 }
                 Ok(output) if !output.status.success() => self.config.sess.fatal(&format!(
                     "Dlltool could not create import library: {}\n{}",
diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index 26343561959..237aef1cf23 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -126,7 +126,7 @@ pub fn parse_cfgspecs(cfgspecs: Vec<String>) -> FxHashSet<(String, Option<String
 
                 // If the user tried to use a key="value" flag, but is missing the quotes, provide
                 // a hint about how to resolve this.
-                if s.contains("=") && !s.contains("=\"") && !s.ends_with("\"") {
+                if s.contains('=') && !s.contains("=\"") && !s.ends_with('"') {
                     error!(concat!(
                         r#"expected `key` or `key="value"`, ensure escaping is appropriate"#,
                         r#" for your shell, try 'key="value"' or key=\"value\""#
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 0115d498a7f..4898a4844b9 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -1702,11 +1702,11 @@ impl<'a> Parser<'a> {
 
         // Try to lowercase the prefix if it's a valid base prefix.
         fn fix_base_capitalisation(s: &str) -> Option<String> {
-            if let Some(stripped) = s.strip_prefix("B") {
+            if let Some(stripped) = s.strip_prefix('B') {
                 Some(format!("0b{stripped}"))
-            } else if let Some(stripped) = s.strip_prefix("O") {
+            } else if let Some(stripped) = s.strip_prefix('O') {
                 Some(format!("0o{stripped}"))
-            } else if let Some(stripped) = s.strip_prefix("X") {
+            } else if let Some(stripped) = s.strip_prefix('X') {
                 Some(format!("0x{stripped}"))
             } else {
                 None
diff --git a/compiler/rustc_typeck/src/check/expr.rs b/compiler/rustc_typeck/src/check/expr.rs
index 82cda5a2f2e..0347b6a4ab8 100644
--- a/compiler/rustc_typeck/src/check/expr.rs
+++ b/compiler/rustc_typeck/src/check/expr.rs
@@ -1587,10 +1587,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     ) {
         let len = remaining_fields.len();
 
-        let mut displayable_field_names =
-            remaining_fields.keys().map(|ident| ident.as_str()).collect::<Vec<_>>();
-
-        displayable_field_names.sort();
+        let mut displayable_field_names: Vec<&str> =
+            remaining_fields.keys().map(|ident| ident.as_str()).collect();
+        // sorting &str primitives here, sort_unstable is ok
+        displayable_field_names.sort_unstable();
 
         let mut truncated_fields_error = String::new();
         let remaining_fields_names = match &displayable_field_names[..] {