feat: support raw ref operator (#4046)

Author: calebcartwright

rustfmt-core/rustfmt-lib/src/expr.rs

@@ -2039,14 +2039,16 @@ pub(crate) fn prefer_next_line(
 
 fn rewrite_expr_addrof(
     context: &RewriteContext<'_>,
-    _borrow_kind: ast::BorrowKind,
+    borrow_kind: ast::BorrowKind,
     mutability: ast::Mutability,
     expr: &ast::Expr,
     shape: Shape,
 ) -> Option<String> {
-    let operator_str = match mutability {
-        ast::Mutability::Not => "&",
-        ast::Mutability::Mut => "&mut ",
+    let operator_str = match (mutability, borrow_kind) {
+        (ast::Mutability::Not, ast::BorrowKind::Ref) => "&",
+        (ast::Mutability::Not, ast::BorrowKind::Raw) => "&raw const ",
+        (ast::Mutability::Mut, ast::BorrowKind::Ref) => "&mut ",
+        (ast::Mutability::Mut, ast::BorrowKind::Raw) => "&raw mut ",
     };
     rewrite_unary_prefix(context, operator_str, expr, shape)
 }

rustfmt-core/rustfmt-lib/tests/source/expr.rs

@@ -218,6 +218,10 @@ fn returns() {
 fn addrof() {
     &    mut(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa+bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb);
     &    (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa+bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb);
+
+    // raw reference operator
+    & raw   const  a;
+    & raw   mut    b;   
 }
 
 fn casts() {

rustfmt-core/rustfmt-lib/tests/target/expr.rs

@@ -251,6 +251,10 @@ fn addrof() {
         + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb);
     &(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
         + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb);
+
+    // raw reference operator
+    &raw const a;
+    &raw mut b;
 }
 
 fn casts() {