remove some redundant clones

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -1204,7 +1204,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 };
                                 err.multipart_suggestion_verbose(
                                     msg,
-                                    sugg.clone(),
+                                    sugg,
                                     Applicability::MaybeIncorrect,
                                 );
                                 for error in errors {

compiler/rustc_middle/src/ty/consts.rs

@@ -30,7 +30,7 @@ impl<'tcx> IntoKind for Const<'tcx> {
     type Kind = ConstKind<'tcx>;
 
     fn kind(self) -> ConstKind<'tcx> {
-        self.kind().clone()
+        self.kind()
     }
 }
 

compiler/rustc_resolve/src/imports.rs

@@ -1002,7 +1002,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                             UNUSED_IMPORTS,
                             id,
                             import.span,
-                            msg.to_string(),
+                            msg,
                             BuiltinLintDiagnostics::RedundantImportVisibility {
                                 max_vis: max_vis.to_string(def_id, self.tcx),
                                 span: import.span,

compiler/stable_mir/src/target.rs

@@ -11,7 +11,7 @@ pub struct MachineInfo {
 
 impl MachineInfo {
     pub fn target() -> MachineInfo {
-        with(|cx| cx.target_info().clone())
+        with(|cx| cx.target_info())
     }
 
     pub fn target_endianess() -> Endian {