Also traverse module type aliases

src/analysis/locate.ml

@@ -311,18 +311,27 @@ let load_cmt ~config comp_unit ml_or_mli =
   | None -> Error ()
 
 let scrape_alias ~env ~fallback_uid ~namespace path =
+  let find_type_and_uid ~env ~namespace path =
+    match namespace with
+    | Shape.Sig_component_kind.Module ->
+      let { Types.md_type; md_uid; _ } = Env.find_module path env in
+      md_type, md_uid
+    | Module_type ->
+      begin match Env.find_modtype path env with
+      | { Types.mtd_type = Some mtd_type; mtd_uid; _ } ->
+        mtd_type, mtd_uid
+      | _ -> raise Not_found
+    end
+    | _ -> raise Not_found
+  in
   let rec non_alias_declaration_uid ~fallback_uid path =
-    match Env.find_module path env with
-    | { md_type = Mty_alias path; md_uid = fallback_uid; _ } ->
+    match find_type_and_uid ~env ~namespace path with
+    | (Mty_alias path | Mty_ident path), fallback_uid ->
         non_alias_declaration_uid ~fallback_uid path
-    | { md_type = Mty_ident _ | Mty_signature _ | Mty_functor _ | Mty_for_hole;
-        md_uid; _ }-> md_uid
+    | _, md_uid -> md_uid
     | exception Not_found -> fallback_uid
   in
-  match namespace with
-  | Shape.Sig_component_kind.Module ->
-    non_alias_declaration_uid ~fallback_uid path
-  | _ -> fallback_uid
+  non_alias_declaration_uid ~fallback_uid path
 
 let uid_of_path ~config ~env ~ml_or_mli ~decl_uid path namespace =
   let module Shape_reduce =

tests/test-dirs/locate/issue1667.t

@@ -6,6 +6,8 @@
   > end
   > 
   > module M : B.T = struct end
+  > module type T2 = B.T
+  > module M2 : T2 = struct end
   > EOF
 
   $ $MERLIN single locate -look-for mli -position 7:13 \
@@ -27,3 +29,14 @@
       "col": 2
     }
   }
+
+
+  $ $MERLIN single locate -look-for mli -position 9:12 \
+  > -filename ./main.ml < ./main.ml | jq '.value'
+  {
+    "file": "$TESTCASE_ROOT/main.ml",
+    "pos": {
+      "line": 2,
+      "col": 2
+    }
+  }