[nullsafe][logs] More logs

Summary:
1. Log cases when we fall back to default while typechecking (we aim to
gradually reduce their usage)
2. Log high level operations when checking field assignment

Reviewed By: ngorogiannis

Differential Revision: D20334923

fbshipit-source-id: 80c45b29e

infer/src/nullsafe/eradicateChecks.ml

@@ -9,6 +9,8 @@ open! IStd
 
 (** Module for the checks called by Eradicate. *)
 
+module L = Logging
+
 let report_error tenv = TypeErr.report_error (EradicateCheckers.report_error tenv)
 
 let explain_expr tenv node e =
@@ -117,15 +119,18 @@ let check_condition_for_redundancy tenv ~is_always_true find_canonical_duplicate
 (** Check an assignment to a field. *)
 let check_field_assignment ~nullsafe_mode tenv find_canonical_duplicate curr_pdesc node instr_ref
     typestate exp_lhs exp_rhs typ loc fname annotated_field_opt typecheck_expr : unit =
+  L.d_with_indent ~name:"check_field_assignment" (fun () ->
       let curr_pname = Procdesc.get_proc_name curr_pdesc in
       let curr_pattrs = Procdesc.get_attributes curr_pdesc in
       let t_lhs, inferred_nullability_lhs =
+        L.d_strln "Typechecking lhs" ;
         typecheck_expr node instr_ref curr_pdesc typestate exp_lhs
           (* TODO(T54687014) optimistic default might be an unsoundness issue - investigate *)
           (typ, InferredNullability.create TypeOrigin.OptimisticFallback)
           loc
       in
       let _, inferred_nullability_rhs =
+        L.d_strln "Typechecking rhs" ;
         typecheck_expr node instr_ref curr_pdesc typestate exp_rhs
           (* TODO(T54687014) optimistic default might be an unsoundness issue - investigate *)
           (typ, InferredNullability.create TypeOrigin.OptimisticFallback)
@@ -166,7 +171,7 @@ let check_field_assignment ~nullsafe_mode tenv find_canonical_duplicate curr_pde
                  ; assignment_location= loc
                  ; rhs_origin
                  ; assignment_type= AssignmentRule.AssigningToField fname })
-          (Some instr_ref) loc curr_pdesc )
+              (Some instr_ref) loc curr_pdesc ) )
 
 
 (* Check if the field declared as not nullable (implicitly or explicitly). If the field is

infer/src/nullsafe/typeCheck.ml

@@ -131,9 +131,15 @@ let rec typecheck_expr ~nullsafe_mode find_canonical_duplicate visited checks te
           (* We already considered case of null literal above, so this is a non-null const. *)
           (typ, InferredNullability.create (TypeOrigin.NonnullConst loc))
       | Exp.Lvar pvar ->
-          Option.value (TypeState.lookup_pvar pvar typestate) ~default:tr_default
+          TypeState.lookup_pvar pvar typestate
+          |> IOption.if_none_eval ~f:(fun () ->
+                 L.d_strln "WARNING: could not lookup Pvar in typestate: fallback to default" ;
+                 tr_default )
       | Exp.Var id ->
-          Option.value (TypeState.lookup_id id typestate) ~default:tr_default
+          TypeState.lookup_id id typestate
+          |> IOption.if_none_eval ~f:(fun () ->
+                 L.d_strln "WARNING: could not lookup Id in typestate: fallback to default" ;
+                 tr_default )
       | Exp.Exn e1 ->
           typecheck_expr ~nullsafe_mode find_canonical_duplicate visited checks tenv node instr_ref
             curr_pdesc typestate e1 tr_default loc
@@ -154,6 +160,7 @@ let rec typecheck_expr ~nullsafe_mode find_canonical_duplicate visited checks te
                 , InferredNullability.create
                     (TypeOrigin.Field {object_origin; field_name; field_type; access_loc= loc}) )
             | None ->
+                L.d_strln "WARNING: could not lookup field annotation: fallback to default" ;
                 tr_default
           in
           if checks.eradicate then
@@ -177,6 +184,7 @@ let rec typecheck_expr ~nullsafe_mode find_canonical_duplicate visited checks te
           let typ, _ = tr_default in
           (typ, InferredNullability.create TypeOrigin.ArrayAccess)
       | _ ->
+          L.d_strln "WARNING: unknown expression: fallback to default" ;
           tr_default )