Some style tweaks to our equality boilerplate code in pkg_rules (#12759)

Signed-off-by: Rudi Grinberg <[email protected]>

Author: rgrinberg

src/dune_rules/pkg_rules.ml

@@ -1198,12 +1198,24 @@ module DB = struct
       ; dep_pkg_digest : Pkg_digest.t
       }
 
+    let dep_equal (dep : dep) { dep_pkg; dep_loc; dep_pkg_digest } =
+      Pkg.equal dep.dep_pkg dep_pkg
+      && Loc.equal dep.dep_loc dep_loc
+      && Pkg_digest.equal dep.dep_pkg_digest dep_pkg_digest
+    ;;
+
     type entry =
       { pkg : Pkg.t
       ; deps : dep list
       ; pkg_digest : Pkg_digest.t
       }
 
+    let entry_equal (entry : entry) { pkg; deps; pkg_digest } =
+      Pkg.equal entry.pkg pkg
+      && List.equal dep_equal entry.deps deps
+      && Pkg_digest.equal entry.pkg_digest pkg_digest
+    ;;
+
     let entries_by_name_of_lock_dir
           (lock_dir : Dune_pkg.Lock_dir.t)
           ~platform
@@ -1257,18 +1269,7 @@ module DB = struct
     (* Associate each package's digest with the package and its dependencies. *)
     type t = entry Pkg_digest.Map.t
 
-    let equal a b =
-      Pkg_digest.Map.equal a b ~equal:(fun (entry : entry) { pkg; deps; pkg_digest } ->
-        Pkg.equal entry.pkg pkg
-        && List.equal
-             (fun (dep : dep) { dep_pkg; dep_loc; dep_pkg_digest } ->
-                Pkg.equal dep.dep_pkg dep_pkg
-                && Loc.equal dep.dep_loc dep_loc
-                && Pkg_digest.equal dep.dep_pkg_digest dep_pkg_digest)
-             entry.deps
-             deps
-        && Pkg_digest.equal entry.pkg_digest pkg_digest)
-    ;;
+    let equal = Pkg_digest.Map.equal ~equal:entry_equal
 
     let of_lock_dir lock_dir ~platform ~system_provided =
       entries_by_name_of_lock_dir lock_dir ~platform ~system_provided
@@ -1337,12 +1338,10 @@ module DB = struct
     ; system_provided : Package.Name.Set.t
     }
 
-  let equal t t2 =
-    phys_equal t t2
-    ||
-    let { pkg_digest_table; system_provided } = t2 in
-    Pkg_table.equal t.pkg_digest_table pkg_digest_table
-    && Package.Name.Set.equal t.system_provided system_provided
+  let equal t ({ pkg_digest_table; system_provided } as t') =
+    phys_equal t t'
+    || (Pkg_table.equal t.pkg_digest_table pkg_digest_table
+        && Package.Name.Set.equal t.system_provided system_provided)
   ;;
 
   let hash = `Do_not_hash
@@ -1435,8 +1434,7 @@ end = struct
       && DB.equal db t.db
     ;;
 
-    let hash { db; pkg_digest; universe } =
-      let _ = db in
+    let hash { db = _; pkg_digest; universe } =
       Tuple.T2.hash Pkg_digest.hash Package_universe.hash (pkg_digest, universe)
     ;;