diff --git a/infer/src/nullsafe/AnnotatedSignature.ml b/infer/src/nullsafe/AnnotatedSignature.ml
index 34f07bad8..7485329eb 100644
--- a/infer/src/nullsafe/AnnotatedSignature.ml
+++ b/infer/src/nullsafe/AnnotatedSignature.ml
@@ -11,10 +11,6 @@ module L = Logging
 type t = {ret: Annot.Item.t * Typ.t; params: (Mangled.t * Annot.Item.t * Typ.t) list}
 [@@deriving compare]
 
-type annotation = Nullable [@@deriving compare]
-
-let ia_is ann ia = match ann with Nullable -> Annotations.ia_is_nullable ia
-
 let get proc_attributes : t =
   let method_annotation = proc_attributes.ProcAttributes.method_annotation in
   let formals = proc_attributes.ProcAttributes.formals in
@@ -58,17 +54,17 @@ let pp proc_name fmt annotated_signature =
 
 let mk_ann_str s = {Annot.class_name= s; parameters= []}
 
-let mk_ann = function Nullable -> mk_ann_str Annotations.nullable
+let mk_ia_nullable ia =
+  if Annotations.ia_is_nullable ia then ia else (mk_ann_str Annotations.nullable, true) :: ia
 
-let mk_ia ann ia = if ia_is ann ia then ia else (mk_ann ann, true) :: ia
 
-let mark_ia ann ia x = if x then mk_ia ann ia else ia
+let mark_ia_nullability ia x = if x then mk_ia_nullable ia else ia
 
-let mark proc_name ann asig (b, bs) =
+let mark_nullability proc_name asig (b, bs) =
   let ia, t = asig.ret in
-  let ret' = (mark_ia ann ia b, t) in
+  let ret' = (mark_ia_nullability ia b, t) in
   let mark_param (s, ia, t) x =
-    let ia' = if x then mk_ia ann ia else ia in
+    let ia' = if x then mk_ia_nullable ia else ia in
     (s, ia', t)
   in
   let params' =
diff --git a/infer/src/nullsafe/AnnotatedSignature.mli b/infer/src/nullsafe/AnnotatedSignature.mli
index 7c71aa6dc..62e87eb49 100644
--- a/infer/src/nullsafe/AnnotatedSignature.mli
+++ b/infer/src/nullsafe/AnnotatedSignature.mli
@@ -14,19 +14,17 @@ type t =
   ; params: (Mangled.t * Annot.Item.t * Typ.t) list  (** Annotated parameters. *) }
 [@@deriving compare]
 
-type annotation = Nullable [@@deriving compare]
-
 val param_has_annot : (Annot.Item.t -> bool) -> Pvar.t -> t -> bool
 (** Check if the given parameter has an annotation in the given signature *)
 
-val mark : Typ.Procname.t -> annotation -> t -> bool * bool list -> t
-(** Mark the annotated signature with the given annotation map. *)
+val mark_nullability : Typ.Procname.t -> t -> bool * bool list -> t
+(** Mark the annotated signature with the given nullability of the ret value and given nullability of the params ). *)
 
 val get : ProcAttributes.t -> t
 (** Get a method signature with annotations from a proc_attributes. *)
 
-val mk_ia : annotation -> Annot.Item.t -> Annot.Item.t
-(** Add the annotation to the item_annotation. *)
+val mk_ia_nullable : Annot.Item.t -> Annot.Item.t
+(** Add the nullable annotation to the item_annotation, if not already present. *)
 
 val pp : Typ.Procname.t -> Format.formatter -> t -> unit
 (** Pretty print a method signature with annotations. *)
diff --git a/infer/src/nullsafe/eradicateChecks.ml b/infer/src/nullsafe/eradicateChecks.ml
index 419757500..6eb83c03c 100644
--- a/infer/src/nullsafe/eradicateChecks.ml
+++ b/infer/src/nullsafe/eradicateChecks.ml
@@ -18,8 +18,7 @@ let get_field_annotation tenv fn typ =
       let ia' =
         (* TODO (t4968422) eliminate not !Config.eradicate check by marking fields as nullified *)
         (* outside of Eradicate in some other way *)
-        if not Config.eradicate then AnnotatedSignature.mk_ia AnnotatedSignature.Nullable ia
-        else ia
+        if not Config.eradicate then AnnotatedSignature.mk_ia_nullable ia else ia
       in
       Some (t, ia')
 
diff --git a/infer/src/nullsafe/models.ml b/infer/src/nullsafe/models.ml
index 13535fa87..b36ac93a6 100644
--- a/infer/src/nullsafe/models.ml
+++ b/infer/src/nullsafe/models.ml
@@ -35,7 +35,7 @@ let get_modelled_annotated_signature proc_attributes =
   let lookup_models_nullable ann_sig =
     try
       let mark = Hashtbl.find annotated_table_nullable proc_id in
-      AnnotatedSignature.mark proc_name AnnotatedSignature.Nullable ann_sig mark
+      AnnotatedSignature.mark_nullability proc_name ann_sig mark
     with Caml.Not_found -> ann_sig
   in
   annotated_signature |> lookup_models_nullable
diff --git a/infer/src/nullsafe/typeAnnotation.ml b/infer/src/nullsafe/typeAnnotation.ml
index d9c04e075..7e8ce98ed 100644
--- a/infer/src/nullsafe/typeAnnotation.ml
+++ b/infer/src/nullsafe/typeAnnotation.ml
@@ -9,19 +9,13 @@ open! IStd
 
 (** Module to represent annotations on types. *)
 
-module AnnotationsMap = Caml.Map.Make (struct
-  type t = AnnotatedSignature.annotation [@@deriving compare]
-end)
-
-type t = {map: bool AnnotationsMap.t; origin: TypeOrigin.t} [@@deriving compare]
+type t = {is_nullable: bool; origin: TypeOrigin.t} [@@deriving compare]
 
 let equal = [%compare.equal: t]
 
-let is_nullable ta = try AnnotationsMap.find Nullable ta.map with Caml.Not_found -> false
-
-let set_nullable b ta =
-  if Bool.equal (is_nullable ta) b then ta else {ta with map= AnnotationsMap.add Nullable b ta.map}
+let is_nullable ta = ta.is_nullable
 
+let set_nullable b ta = if Bool.equal (is_nullable ta) b then ta else {ta with is_nullable= b}
 
 let descr_origin ta =
   let descr_opt = TypeOrigin.get_description ta.origin in
@@ -56,10 +50,7 @@ let origin_is_fun_library ta =
       false
 
 
-let const_nullable b origin =
-  let ta = {origin; map= AnnotationsMap.empty} in
-  set_nullable b ta
-
+let const_nullable is_nullable origin = {origin; is_nullable}
 
 let with_origin ta o = {ta with origin= o}