[textual] Translate __Infer_Constant__ attribute as const qualifier

Summary:
This diff translates the `__Infer_Constant__` attribute of textual as
the const qualifier in SIL.

Reviewed By: jvillard

Differential Revision: D49874692

fbshipit-source-id: 417a0cbe4757d7b06a95602cb435d0e27c554627

infer/src/textual/Textual.ml

@@ -197,6 +197,8 @@ module Attr = struct
 
   let is_async {name; values} = String.equal name "async" && List.is_empty values
 
+  let is_const {name; values} = String.equal name "__Infer_Constant__" && List.is_empty values
+
   let is_curry {name; values} = String.equal name "curry" && List.is_empty values
 
   let is_final {name; values} = String.equal name "final" && List.is_empty values

infer/src/textual/Textual.mli

@@ -99,6 +99,8 @@ module Attr : sig
 
   val is_async : t -> bool
 
+  val is_const : t -> bool
+
   val mk_trait : t
 
   val pp : F.formatter -> t -> unit [@@warning "-unused-value-declaration"]

infer/src/textual/TextualSil.ml

@@ -199,8 +199,9 @@ let wildcard_sil_fieldname lang name =
 module TypBridge = struct
   open Typ
 
-  let rec to_sil lang (typ : t) : SilTyp.t =
-    let quals = SilTyp.mk_type_quals () in
+  let rec to_sil lang ?(attrs = []) (typ : t) : SilTyp.t =
+    let is_const = List.exists attrs ~f:Textual.Attr.is_const in
+    let quals = SilTyp.mk_type_quals ~is_const () in
     let desc : SilTyp.desc =
       match typ with
       | Int ->
@@ -477,7 +478,9 @@ module StructBridge = struct
     in
     let fields =
       List.map fields ~f:(fun (fdecl : FieldDecl.t) ->
-          (FieldDeclBridge.to_sil lang fdecl, TypBridge.to_sil lang fdecl.typ, Annot.Item.empty) )
+          ( FieldDeclBridge.to_sil lang fdecl
+          , TypBridge.to_sil lang ~attrs:fdecl.attributes fdecl.typ
+          , Annot.Item.empty ) )
     in
     let annots =
       List.filter_map attributes ~f:(fun attr ->
@@ -587,7 +590,10 @@ module ExpBridge = struct
             L.die InternalError "field %a.%a has not been declared" TypeName.pp
               field.enclosing_class FieldName.pp field.name
         | Some field ->
-            Lfield (aux exp, FieldDeclBridge.to_sil lang field, TypBridge.to_sil lang field.typ) )
+            Lfield
+              ( aux exp
+              , FieldDeclBridge.to_sil lang field
+              , TypBridge.to_sil lang ~attrs:field.attributes field.typ ) )
       | Index (exp1, exp2) ->
           Lindex (aux exp1, aux exp2)
       | Const const ->
@@ -779,7 +785,10 @@ module InstrBridge = struct
               raise (TextualTransformError [{loc; msg}])
         in
         let pname = ProcDeclBridge.call_to_sil lang procsig callee_procname in
-        let result_type = TypBridge.to_sil lang callee_procname.result_type.typ in
+        let result_type =
+          TypBridge.to_sil lang ~attrs:callee_procname.result_type.attributes
+            callee_procname.result_type.typ
+        in
         let args = List.map ~f:(ExpBridge.to_sil lang decls_env procname) args in
         let formals_types =
           match formals_types with
@@ -954,14 +963,16 @@ module ProcDescBridge = struct
     in
     List.map locals ~f:(fun (var, annotated_typ) ->
         let name = Mangled.from_string var.VarName.value in
-        let typ = TypBridge.to_sil lang annotated_typ.Typ.typ in
+        let typ = TypBridge.to_sil lang ~attrs:annotated_typ.Typ.attributes annotated_typ.Typ.typ in
         make_var_data name typ )
 
 
   let to_sil lang decls_env cfgs ({procdecl; nodes; start; exit_loc} as pdesc) =
     let sourcefile = TextualDecls.source_file decls_env in
     let sil_procname = ProcDeclBridge.to_sil lang procdecl in
-    let sil_ret_type = TypBridge.to_sil lang procdecl.result_type.typ in
+    let sil_ret_type =
+      TypBridge.to_sil lang ~attrs:procdecl.result_type.attributes procdecl.result_type.typ
+    in
     let definition_loc = LocationBridge.to_sil sourcefile procdecl.qualified_name.name.loc in
     let is_hack_async = List.exists procdecl.attributes ~f:Attr.is_async in
     let formals = build_formals lang pdesc in

infer/src/textual/unit/TextualSilTest.ml

@@ -372,3 +372,42 @@ let%expect_test "trait vs class kind" =
       annots: {<>}
       class_info: {HackClassInfo (Trait)}
       dummy: false |}]
+
+
+let%expect_test "const" =
+  let source =
+    {|
+     .source_language = "hack"
+
+     type Uninit::A$static = .kind="class" .static {
+       FIELD: .public .__Infer_Constant__ *HackMixed
+     }
+     |}
+  in
+  let m = parse_module source in
+  let _, tenv = TextualSil.module_to_sil m in
+  F.printf "%a@\n" Tenv.pp tenv ;
+  [%expect
+    {|
+    hack HackMixed
+    fields: {}
+    statics: {}
+    supers: {}
+    objc_protocols: {}
+    methods: {}
+    exported_obj_methods: {}
+    annots: {<>}
+    class_info: {NoInfo}
+    dummy: true
+    hack Uninit::A$static
+    fields: {
+               HackMixed* const  FIELD <>
+             }
+    statics: {}
+    supers: {}
+    objc_protocols: {}
+    methods: {}
+    exported_obj_methods: {}
+    annots: {<>}
+    class_info: {HackClassInfo (Class)}
+    dummy: false |}]