Fix parenthesing of let in class expressions

CHANGES.md

@@ -60,6 +60,7 @@ profile. This started with version 0.26.0.
 - Display `a##b` instead of `a ## b` and similarly for operators that start with # (#2580, @v-gb)
 - \* Fix arrow type indentation with `break-separators=before` (#2598, @Julow)
 - Fix formatting of short `fun` expressions with the janestreet profile (#2593, @Julow)
+- Fix missing parentheses around a let in class expressions (#2599, @Julow)
 
 ### Changes
 - The location of attributes for structure items is now tracked and preserved. (#2247, @EmileTrotignon)

lib/Ast.ml

@@ -1777,6 +1777,7 @@ end = struct
       match c.pcl_desc with
       | Pcl_apply _ -> Some Apply
       | Pcl_structure _ -> Some Apply
+      | Pcl_let _ -> Some Low
       | _ -> None )
     | Top | Pat _ | Mty _ | Mod _ | Sig _ | Str _ | Tli _ | Clf _ | Ctf _
      |Rep | Mb _ | Md _ | Cd _ | Ctd _ ->

test/passing/tests/class_expr.ml

@@ -15,3 +15,8 @@ class c =
         let pci_params = self#list in
         ()
   end
+
+class c =
+  (let () = print_endline "Class init" in
+   with_param )
+    ()