diff --git a/infer/src/nullsafe/InferredNullability.ml b/infer/src/nullsafe/InferredNullability.ml
index 81920cae0..a14724206 100644
--- a/infer/src/nullsafe/InferredNullability.ml
+++ b/infer/src/nullsafe/InferredNullability.ml
@@ -21,10 +21,6 @@ let is_nonnull {nullability} =
   match nullability with Nullable -> false | DeclaredNonnull -> false | Nonnull -> true
 
 
-let set_nullability nullability t = {t with nullability}
-
-let set_nonnull = set_nullability Nullability.Nonnull
-
 let descr_origin t =
   let descr_opt = TypeOrigin.get_description t.origin in
   match descr_opt with
diff --git a/infer/src/nullsafe/InferredNullability.mli b/infer/src/nullsafe/InferredNullability.mli
index d38d04b0a..08ba64ef5 100644
--- a/infer/src/nullsafe/InferredNullability.mli
+++ b/infer/src/nullsafe/InferredNullability.mli
@@ -27,8 +27,6 @@ val is_nonnull_or_declared_nonnull : t -> bool
 
 val is_nonnull : t -> bool
 
-val set_nonnull : t -> t
-
 val descr_origin : t -> TypeErr.origin_descr
 (** Human-readable description of the origin of a value.
   (How did nullsafe infer the nullability )
diff --git a/infer/src/nullsafe/typeCheck.ml b/infer/src/nullsafe/typeCheck.ml
index a820cbe6b..49c5a9908 100644
--- a/infer/src/nullsafe/typeCheck.ml
+++ b/infer/src/nullsafe/typeCheck.ml
@@ -456,10 +456,9 @@ let do_preconditions_check_not_null instr_ref tenv find_canonical_duplicate node
           EradicateChecks.report_error tenv find_canonical_duplicate
             (TypeErr.Condition_redundant (true, EradicateChecks.explain_expr tenv node cond))
             (Some instr_ref) loc curr_pdesc ) ;
-        TypeState.add pvar
-          (* TODO(T54687014) optimistic default might be an unsoundness issue - investigate *)
-          (t, InferredNullability.create TypeOrigin.OptimisticFallback)
-          typestate''
+        let previous_origin = InferredNullability.get_origin nullability in
+        let new_origin = TypeOrigin.InferredNonnull {previous_origin} in
+        TypeState.add pvar (t, InferredNullability.create new_origin) typestate''
     | None ->
         typestate'
   in
@@ -498,11 +497,10 @@ let do_preconditions_check_state instr_ref idenv tenv curr_pname curr_annotated_
   let set_nonnull_to_pvar typestate1 pvar =
     (* handle the annotation flag for pvar *)
     match TypeState.lookup_pvar pvar typestate1 with
-    | Some (t, _) ->
-        TypeState.add pvar
-          (* TODO(T54687014) optimistic default might be an unsoundness issue - investigate *)
-          (t, InferredNullability.create TypeOrigin.OptimisticFallback)
-          typestate1
+    | Some (t, nullability) ->
+        let previous_origin = InferredNullability.get_origin nullability in
+        let new_origin = TypeOrigin.InferredNonnull {previous_origin} in
+        TypeState.add pvar (t, InferredNullability.create new_origin) typestate1
     | None ->
         typestate1
   in
@@ -713,7 +711,11 @@ let rec check_condition_for_sil_prune tenv idenv calls_this find_canonical_dupli
       match TypeState.lookup_pvar pvar typestate' with
       | Some (t, current_nullability) ->
           if not (InferredNullability.is_nonnull current_nullability) then
-            let new_nullability = InferredNullability.set_nonnull current_nullability in
+            let new_origin =
+              TypeOrigin.InferredNonnull
+                {previous_origin= InferredNullability.get_origin current_nullability}
+            in
+            let new_nullability = InferredNullability.create new_origin in
             TypeState.add pvar (t, new_nullability) typestate'
           else typestate'
       | None ->
diff --git a/infer/src/nullsafe/typeOrigin.ml b/infer/src/nullsafe/typeOrigin.ml
index b4f6abfe3..5b38d15f7 100644
--- a/infer/src/nullsafe/typeOrigin.ml
+++ b/infer/src/nullsafe/typeOrigin.ml
@@ -18,6 +18,9 @@ type t =
   | MethodCall of method_call_origin  (** A result of a method call *)
   | New  (** A new object creation *)
   | ArrayLengthResult  (** integer value - result of accessing array.length *)
+  | InferredNonnull of {previous_origin: t}
+      (** The value is inferred as non-null during flow-sensitive type inference
+          (most commonly from relevant condition branch or assertion explicitly comparing the value with `null`) *)
   (* Below are two special values. *)
   | OptimisticFallback
       (** Something went wrong during typechecking.
@@ -50,6 +53,7 @@ let get_nullability = function
   | This (* `this` can not be null according to Java rules *)
   | New (* In Java `new` always create a non-null object  *)
   | ArrayLengthResult (* integer hence non-nullable *)
+  | InferredNonnull _
   | OptimisticFallback (* non-null is the most optimistic type *)
   | Undef (* This is a very special case, assigning non-null is a technical trick *) ->
       Nullability.Nonnull
@@ -81,6 +85,8 @@ let rec to_string = function
       "New"
   | ArrayLengthResult ->
       "ArrayLength"
+  | InferredNonnull _ ->
+      "InferredNonnull"
   | OptimisticFallback ->
       "OptimisticFallback"
   | Undef ->
@@ -118,7 +124,7 @@ let get_description origin =
      But for these issues we currently don't print origins in the error string.
      It is a good idea to change this and start printing origins for these origins as well.
   *)
-  | This | New | NonnullConst _ | ArrayLengthResult ->
+  | This | New | NonnullConst _ | ArrayLengthResult | InferredNonnull _ ->
       None
   (* Two special cases - should not really occur in normal code *)
   | OptimisticFallback | Undef ->
diff --git a/infer/src/nullsafe/typeOrigin.mli b/infer/src/nullsafe/typeOrigin.mli
index 99fc3fe6d..fa890076c 100644
--- a/infer/src/nullsafe/typeOrigin.mli
+++ b/infer/src/nullsafe/typeOrigin.mli
@@ -16,6 +16,9 @@ type t =
   | MethodCall of method_call_origin  (** A result of a method call *)
   | New  (** A new object creation *)
   | ArrayLengthResult  (** integer value - result of accessing array.length *)
+  | InferredNonnull of {previous_origin: t}
+      (** The value is inferred as non-null during flow-sensitive type inference
+          (most commonly from relevant condition branch or assertion explicitly comparing the value with `null`) *)
   (* Below are two special values. *)
   | OptimisticFallback
       (** Something went wrong during typechecking.