[infer] Distinguish dummy struct types from normal ones when merging tenv

Summary:
Some field types of structs are missing in Java. The reason is:

* When capture, empty struct types are added without their fields.
* The empty struct types are overwritten to the global tenv when merging all tenvs.

As a fix, this diff add a boolean field, `dummy`, in `Typ.Struct.t`, then avoids that non-dummy types are replaced by dummy types.

Reviewed By: ngorogiannis

Differential Revision: D18657323

fbshipit-source-id: 4a263f8e7

infer/src/IR/Tenv.ml

@@ -29,10 +29,11 @@ let pp fmt (tenv : t) =
 let create () = TypenameHash.create 1000
 
 (** Construct a struct type in a type environment *)
-let mk_struct tenv ?default ?fields ?statics ?methods ?exported_objc_methods ?supers ?annots name =
+let mk_struct tenv ?default ?fields ?statics ?methods ?exported_objc_methods ?supers ?annots ?dummy
+    name =
   let struct_typ =
     Typ.Struct.internal_mk_struct ?default ?fields ?statics ?methods ?exported_objc_methods ?supers
-      ?annots ()
+      ?annots ?dummy ()
   in
   TypenameHash.replace tenv name struct_typ ;
   struct_typ
@@ -99,7 +100,13 @@ module SQLite : SqliteUtils.Data with type t = per_file = struct
         FileLocal (Serializer.deserialize blob)
 end
 
-let merge ~src ~dst = TypenameHash.iter (fun pname cfg -> TypenameHash.replace dst pname cfg) src
+let merge ~src ~dst =
+  TypenameHash.iter
+    (fun pname cfg ->
+      if (not (Typ.Struct.is_dummy cfg)) || not (TypenameHash.mem dst pname) then
+        TypenameHash.replace dst pname cfg )
+    src
+
 
 let merge_per_file ~src ~dst =
   match (src, dst) with

infer/src/IR/Tenv.mli

@@ -41,6 +41,7 @@ val mk_struct :
   -> ?exported_objc_methods:Typ.Procname.t list
   -> ?supers:Typ.Name.t list
   -> ?annots:Annot.Item.t
+  -> ?dummy:bool
   -> Typ.Name.t
   -> Typ.Struct.t
 (** Construct a struct_typ, normalizing field types *)

infer/src/IR/Typ.ml

@@ -1518,7 +1518,8 @@ module Struct = struct
     ; supers: Name.t list  (** superclasses *)
     ; methods: Procname.t list  (** methods defined *)
     ; exported_objc_methods: Procname.t list  (** methods in ObjC interface, subset of [methods] *)
-    ; annots: Annot.Item.t  (** annotations *) }
+    ; annots: Annot.Item.t  (** annotations *)
+    ; dummy: bool  (** dummy struct for class including static method *) }
 
   type lookup = Name.t -> t option
 
@@ -1554,21 +1555,22 @@ module Struct = struct
 
 
   let internal_mk_struct ?default ?fields ?statics ?methods ?exported_objc_methods ?supers ?annots
-      () =
+      ?dummy () =
     let default_ =
       { fields= []
       ; statics= []
       ; methods= []
       ; exported_objc_methods= []
       ; supers= []
-      ; annots= Annot.Item.empty }
+      ; annots= Annot.Item.empty
+      ; dummy= false }
     in
     let mk_struct_ ?(default = default_) ?(fields = default.fields) ?(statics = default.statics)
         ?(methods = default.methods) ?(exported_objc_methods = default.exported_objc_methods)
-        ?(supers = default.supers) ?(annots = default.annots) () =
-      {fields; statics; methods; exported_objc_methods; supers; annots}
+        ?(supers = default.supers) ?(annots = default.annots) ?(dummy = default.dummy) () =
+      {fields; statics; methods; exported_objc_methods; supers; annots; dummy}
     in
-    mk_struct_ ?default ?fields ?statics ?methods ?exported_objc_methods ?supers ?annots ()
+    mk_struct_ ?default ?fields ?statics ?methods ?exported_objc_methods ?supers ?annots ?dummy ()
 
 
   (** the element typ of the final extensible array in the given typ, if any *)
@@ -1617,4 +1619,7 @@ module Struct = struct
           None )
     | _ ->
         None
+
+
+  let is_dummy {dummy} = dummy
 end

infer/src/IR/Typ.mli

@@ -697,7 +697,8 @@ module Struct : sig
     ; supers: Name.t list  (** supers *)
     ; methods: Procname.t list  (** methods defined *)
     ; exported_objc_methods: Procname.t list  (** methods in ObjC interface, subset of [methods] *)
-    ; annots: Annot.Item.t  (** annotations *) }
+    ; annots: Annot.Item.t  (** annotations *)
+    ; dummy: bool  (** dummy struct for class including static method *) }
 
   type lookup = Name.t -> t option
 
@@ -714,6 +715,7 @@ module Struct : sig
     -> ?exported_objc_methods:Procname.t list
     -> ?supers:Name.t list
     -> ?annots:Annot.Item.t
+    -> ?dummy:bool
     -> unit
     -> t
   (** Construct a struct_typ, normalizing field types *)
@@ -728,4 +730,6 @@ module Struct : sig
   val get_field_type_and_annotation :
     lookup:lookup -> Fieldname.t -> typ -> (typ * Annot.Item.t) option
   (** Return the type of the field [fn] and its annotation, None if [typ] has no field named [fn] *)
+
+  val is_dummy : t -> bool
 end

infer/src/java/jTransType.ml

@@ -339,12 +339,12 @@ and get_class_struct_typ =
     | Some struct_typ ->
         struct_typ
     | None when JBasics.ClassSet.mem cn !seen ->
-        Tenv.mk_struct tenv name
+        Tenv.mk_struct ~dummy:true tenv name
     | None -> (
         seen := JBasics.ClassSet.add cn !seen ;
         match JClasspath.lookup_node cn program with
         | None ->
-            Tenv.mk_struct tenv name
+            Tenv.mk_struct ~dummy:true tenv name
         | Some node ->
             let create_super_list interface_names =
               List.iter ~f:(fun cn -> ignore (get_class_struct_typ program tenv cn)) interface_names ;