Taking a raw ref of a deref is always safe

Author: Veykril

src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/unsafe_check.rs

@@ -99,10 +99,17 @@ fn walk_unsafe(
         }
         Expr::Path(path) => mark_unsafe_path(path, current.into()),
         Expr::Ref { expr, rawness: Rawness::RawPtr, mutability: _ } => {
-            if let Expr::Path(_) = body.exprs[*expr] {
-                // Do not report unsafe for `addr_of[_mut]!(EXTERN_OR_MUT_STATIC)`,
-                // see https://github.com/rust-lang/rust/pull/125834.
-                return;
+            match self.body.exprs[*expr] {
+                Expr::Path(_) => return,
+                // https://github.com/rust-lang/rust/pull/129248
+                // Taking a raw ref to a deref place expr is always safe.
+                Expr::UnaryOp { expr, op: UnaryOp::Deref } => {
+                    self.body
+                        .walk_child_exprs_without_pats(expr, |child| self.walk_expr(child));
+
+                    return;
+                }
+                _ => (),
             }
         }
         Expr::MethodCall { .. } => {

src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/missing_unsafe.rs

@@ -631,4 +631,19 @@ fn main() {
 "#,
         );
     }
+
+    #[test]
+    fn raw_ref_reborrow_is_safe() {
+        check_diagnostics(
+            r#"
+fn main() {
+    let ptr: *mut i32;
+    let _addr = &raw const *ptr;
+    let local = 1;
+    let ptr = &local as *const i32;
+    let _addr = &raw const *ptr;
+}
+"#,
+        )
+    }
 }