From 38c07c7ca5f5a1bc65767b7dd8091b9992fc72a1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Mi=C4=85sko?= <tomasz.miasko@gmail.com>
Date: Thu, 29 Jul 2021 00:00:00 +0000
Subject: [PATCH] Implement `Printer` for `&mut SymbolPrinter`

to avoid passing `SymbolPrinter` by value.
---
 compiler/rustc_symbol_mangling/src/legacy.rs | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/compiler/rustc_symbol_mangling/src/legacy.rs b/compiler/rustc_symbol_mangling/src/legacy.rs
index 0c64fe6ea60..1b4e6b4e381 100644
--- a/compiler/rustc_symbol_mangling/src/legacy.rs
+++ b/compiler/rustc_symbol_mangling/src/legacy.rs
@@ -55,7 +55,8 @@ pub(super) fn mangle(
 
     let hash = get_symbol_hash(tcx, instance, instance_ty, instantiating_crate);
 
-    let mut printer = SymbolPrinter { tcx, path: SymbolPath::new(), keep_within_component: false }
+    let mut printer = SymbolPrinter { tcx, path: SymbolPath::new(), keep_within_component: false };
+    printer
         .print_def_path(
             def_id,
             if let ty::InstanceDef::DropGlue(_, _) = instance.def {
@@ -198,7 +199,7 @@ struct SymbolPrinter<'tcx> {
 // `PrettyPrinter` aka pretty printing of e.g. types in paths,
 // symbol names should have their own printing machinery.
 
-impl Printer<'tcx> for SymbolPrinter<'tcx> {
+impl Printer<'tcx> for &mut SymbolPrinter<'tcx> {
     type Error = fmt::Error;
 
     type Path = Self;
@@ -242,7 +243,7 @@ impl Printer<'tcx> for SymbolPrinter<'tcx> {
         Ok(self)
     }
 
-    fn print_const(mut self, ct: &'tcx ty::Const<'tcx>) -> Result<Self::Const, Self::Error> {
+    fn print_const(self, ct: &'tcx ty::Const<'tcx>) -> Result<Self::Const, Self::Error> {
         // only print integers
         if let ty::ConstKind::Value(ConstValue::Scalar(Scalar::Int { .. })) = ct.val {
             if ct.ty.is_integral() {
@@ -253,7 +254,7 @@ impl Printer<'tcx> for SymbolPrinter<'tcx> {
         Ok(self)
     }
 
-    fn path_crate(mut self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
+    fn path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
         self.write_str(&self.tcx.crate_name(cnum).as_str())?;
         Ok(self)
     }
@@ -344,7 +345,7 @@ impl Printer<'tcx> for SymbolPrinter<'tcx> {
     }
 }
 
-impl PrettyPrinter<'tcx> for SymbolPrinter<'tcx> {
+impl PrettyPrinter<'tcx> for &mut SymbolPrinter<'tcx> {
     fn region_should_not_be_omitted(&self, _region: ty::Region<'_>) -> bool {
         false
     }