[nullsafe][refactor] Use ThirdPartyNonnull instead of heuristic in error rendering

Summary:
Since artempyanykh introduced proper type for third party methods, we don't need
to write a sketchy heuristic in this place.

This will simplify shipping a feature in the follow up diff (otherwise
it would break here).

Reviewed By: artempyanykh

Differential Revision: D20139460

fbshipit-source-id: 00144dc48

infer/src/nullsafe/ErrorRenderingUtils.ml

@@ -101,7 +101,6 @@ let mk_coming_from nullsafe_mode nullability =
 
 let mk_recommendation nullsafe_mode nullability what =
   match (nullsafe_mode, nullability) with
-  | NullsafeMode.Strict, Nullability.ThirdPartyNonnull
   | NullsafeMode.Strict, Nullability.UncheckedNonnull
   | NullsafeMode.Strict, Nullability.LocallyCheckedNonnull ->
       Some (F.sprintf "make %s nullsafe strict" what)
@@ -130,29 +129,34 @@ let get_info object_origin nullsafe_mode bad_nullability =
           (Procname.to_simplified_string ~withclass:true pname)
       in
       let object_loc = call_loc in
+      let what_is_used = "Result of this call" in
+      let+ coming_from_explanation, recommendation, issue_type =
+        match bad_nullability with
+        | Nullability.Null | Nullability.Nullable ->
+            (* This method makes sense only for non-nullable violations *)
+            None
+        | Nullability.StrictNonnull ->
+            (* This method makes sense only for non-nullable violations *)
+            Logging.die InternalError "There should not be type violations involving StrictNonnull"
+        | Nullability.ThirdPartyNonnull ->
             let suggested_third_party_sig_file =
               ThirdPartyAnnotationInfo.lookup_related_sig_file_for_proc
                 (ThirdPartyAnnotationGlobalRepo.get_repo ())
                 pname
             in
-      let what_is_used = "Result of this call" in
-      (* Two main cases: it is either FB owned code or third party.
-         We determine the difference based on presense of suggested_third_party_sig_file.
-      *)
-      let+ coming_from_explanation, recommendation, issue_type =
-        match suggested_third_party_sig_file with
-        | Some sig_file_name ->
-            (* Dereferences or assignment violations with regular Nullables
-               should not be special cased *)
-            if Nullability.equal Nullable bad_nullability then None
-            else
+            let where_to_add_signature =
+              Option.value_map suggested_third_party_sig_file
+                ~f:(fun sig_file_name ->
+                  ThirdPartyAnnotationGlobalRepo.get_user_friendly_third_party_sig_file_name
+                    ~filename:sig_file_name )
+                  (* this can happen when third party is registered in a deprecated way (not in third party repository) *)
+                ~default:"the third party signature storage"
+            in
             return
               ( "not vetted third party methods"
-                , F.sprintf "add the correct signature to %s"
-                    (ThirdPartyAnnotationGlobalRepo.get_user_friendly_third_party_sig_file_name
-                       ~filename:sig_file_name)
+              , F.sprintf "add the correct signature to %s" where_to_add_signature
               , IssueType.eradicate_unvetted_third_party_in_nullsafe )
-        | None ->
+        | Nullability.UncheckedNonnull | Nullability.LocallyCheckedNonnull ->
             let* from = mk_coming_from nullsafe_mode bad_nullability in
             let+ recommendation =
               let what_to_strictify =

infer/src/nullsafe/ErrorRenderingUtils.mli

@@ -19,9 +19,11 @@ val mk_special_nullsafe_issue :
   -> bad_usage_location:Location.t
   -> TypeOrigin.t
   -> (string * IssueType.t * Location.t) option
-(** Situation when we tried to use nonnull values of incompatible modes. This is disallowed in
-    strict and local mode. Returns a tuple (error message, issue type, error location). NOTE:
-    Location of the error will be NOT in the place when the value is used (that is
+(** Situation when we tried to use nonnull values in a nullsafe mode that does not trust them to be
+    non-nullable. From the user perspective, this case is different from normal nullable assignment
+    or dereference violation: what needs to be described is why does not this mode trust this value
+    (and what are possible actions). Returns a tuple (error message, issue type, error location).
+    NOTE: Location of the error will be NOT in the place when the value is used (that is
     [bad_usage_location]), but where the value is first obtained from. *)
 
 val find_alternative_nonnull_method_description : TypeOrigin.t -> string option