introduce `Mutability::ptr_str`

compiler/rustc_ast_ir/src/lib.rs

@@ -51,6 +51,14 @@ impl Mutability {
         }
     }
 
+    /// Returns `"const"` or `"mut"` depending on the mutability.
+    pub fn ptr_str(self) -> &'static str {
+        match self {
+            Mutability::Not => "const",
+            Mutability::Mut => "mut",
+        }
+    }
+
     /// Returns `""` (empty string) or `"mutably "` depending on the mutability.
     pub fn mutably_str(self) -> &'static str {
         match self {

compiler/rustc_middle/src/mir/pretty.rs

@@ -978,12 +978,7 @@ impl<'tcx> Debug for Rvalue<'tcx> {
             CopyForDeref(ref place) => write!(fmt, "deref_copy {place:#?}"),
 
             AddressOf(mutability, ref place) => {
-                let kind_str = match mutability {
-                    Mutability::Mut => "mut",
-                    Mutability::Not => "const",
-                };
-
-                write!(fmt, "&raw {kind_str} {place:?}")
+                write!(fmt, "&raw {mut_str} {place:?}", mut_str = mutability.ptr_str())
             }
 
             Aggregate(ref kind, ref places) => {

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -671,13 +671,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
                 p!("(", print(ty), ") is ", write("{pat:?}"))
             }
             ty::RawPtr(ty, mutbl) => {
-                p!(write(
-                    "*{} ",
-                    match mutbl {
-                        hir::Mutability::Mut => "mut",
-                        hir::Mutability::Not => "const",
-                    }
-                ));
+                p!(write("*{} ", mutbl.ptr_str()));
                 p!(print(ty))
             }
             ty::Ref(r, ty, mutbl) => {

compiler/rustc_type_ir/src/ty_kind.rs

@@ -373,17 +373,8 @@ impl<I: Interner> DebugWithInfcx<I> for TyKind<I> {
             Array(t, c) => write!(f, "[{:?}; {:?}]", &this.wrap(t), &this.wrap(c)),
             Pat(t, p) => write!(f, "pattern_type!({:?} is {:?})", &this.wrap(t), &this.wrap(p)),
             Slice(t) => write!(f, "[{:?}]", &this.wrap(t)),
-            RawPtr(ty, mutbl) => {
-                match mutbl {
-                    Mutability::Mut => write!(f, "*mut "),
-                    Mutability::Not => write!(f, "*const "),
-                }?;
-                write!(f, "{:?}", &this.wrap(ty))
-            }
-            Ref(r, t, m) => match m {
-                Mutability::Mut => write!(f, "&{:?} mut {:?}", &this.wrap(r), &this.wrap(t)),
-                Mutability::Not => write!(f, "&{:?} {:?}", &this.wrap(r), &this.wrap(t)),
-            },
+            RawPtr(ty, mutbl) => write!(f, "*{} {:?}", mutbl.ptr_str(), this.wrap(ty)),
+            Ref(r, t, m) => write!(f, "&{:?} {}{:?}", this.wrap(r), m.prefix_str(), this.wrap(t)),
             FnDef(d, s) => f.debug_tuple("FnDef").field(d).field(&this.wrap(s)).finish(),
             FnPtr(s) => write!(f, "{:?}", &this.wrap(s)),
             Dynamic(p, r, repr) => match repr {