[hack] fix capture error on splated arguments

Summary:
We already support splated args, but only when they are given to a variadic function. Now they can also be given to a non-variadic function, without capture failure.

The precise static analysis of such situation is left for further work.

Reviewed By: ngorogiannis

Differential Revision:
D55359346

Privacy Context Container: L1208441

fbshipit-source-id: 3d7bd1fca86935d926cc0fa39048747bd725c559

infer/src/textual/TextualDecls.ml

@@ -18,6 +18,13 @@ module ProcEntry = struct
   let desc = function Decl _ -> None | Desc p -> Some p
 
   let signature t lang = ProcDecl.to_sig (decl t) lang
+
+  let remove_formals_types = function
+    | Decl pdecl ->
+        Decl {pdecl with formals_types= None}
+    | Desc pdesc ->
+        let procdecl = {pdesc.procdecl with formals_types= None} in
+        Desc {pdesc with procdecl}
 end
 
 type t =
@@ -107,10 +114,25 @@ let declare_variadic_proc_if_necessary decls = function
       ()
 
 
+(* every declared/implemented function is also given a default proc entry without
+   formals types. This is useful to avoid capture errors with variadic function and/or
+   splated arguments. *)
+let declare_default_if_necessary decls proc =
+  let procsig = ProcEntry.signature proc decls.lang in
+  match procsig with
+  | ProcSig.Hack {qualified_name; arity= Some _} ->
+      let procsig_default = ProcSig.Hack {qualified_name; arity= None} in
+      if not (ProcSig.Hashtbl.mem decls.procs procsig_default) then
+        ProcSig.Hashtbl.add decls.procs procsig_default (ProcEntry.remove_formals_types proc)
+  | _ ->
+      ()
+
+
 let declare_proc decls (proc : ProcEntry.t) =
   let procsig = ProcEntry.signature proc decls.lang in
   let existing_proc = ProcSig.Hashtbl.find_opt decls.procs procsig in
   declare_variadic_proc_if_necessary decls proc ;
+  declare_default_if_necessary decls proc ;
   match (existing_proc, proc) with
   | Some (Desc _), Decl _ ->
       ()

infer/src/textual/unit/TextualSilTest.ml

@@ -50,6 +50,7 @@ let%expect_test "undefined types are included in tenv" =
          supers: {}
          objc_protocols: {}
          methods: {
+                     Foo.f
                      Foo.f#2
                    }
          exported_obj_methods: {}
@@ -83,6 +84,7 @@ let%expect_test "undefined types are included in tenv" =
          supers: {}
          objc_protocols: {}
          methods: {
+                     Bar.f
                      Bar.f#0
                    }
          exported_obj_methods: {}
@@ -217,6 +219,7 @@ let%expect_test "overloads in tenv" =
     supers: {}
     objc_protocols: {}
     methods: {
+                C.f
                 C.f#1
                 C.f#2
               }
@@ -284,6 +287,7 @@ let%expect_test "undefined + overloads in merged tenv" =
     supers: {}
     objc_protocols: {}
     methods: {
+                Dep.f
                 Dep.f#1
                 Dep.f#2
               }

infer/tests/codetoanalyze/hack/capture/snippets/variadic.hack

@@ -82,3 +82,10 @@ trait T {
   public function foo2<reify T>(int $x = 0, int ...$rest): void {}
   public static function static_foo2<reify T>(int $x, int ...$rest): void {}
 }
+
+function arity3(int $arg1, int $arg2, int $arg3): void {}
+
+function call_not_really_variadic_with_splat(): void {
+  $args = tuple(1, 2, 3);
+  arity3(...$args);
+}

infer/tests/codetoanalyze/sil/verif/issues.exp

@@ -20,7 +20,6 @@ basic.sil, line 88, column 4: textual type error: expression 0 has type int, whi
 basic.sil, line 106, column 4: textual type error: expression n1 has type float, while a subtype of int was expected
 basic.sil, line 108, column 4: textual type error: expression n1 has type float, while a subtype of int was expected
 basic.sil, line 110, column 9: textual type error: expression [&y:float] has type float, while a subtype of int was expected
-basic_error_argnum.sil, line 12, column 7: SIL consistency error: function $builtins.bar which can be called with 0 arguments is not declared
 error1.sil, line 12, column 4: SIL syntax error: unexpected token x
 error2.sil, line 19, column 9: SIL consistency error: function g which can be called with 0 arguments is not declared
 error2.sil, line 18, column 13: SIL consistency error: field cell.n is not declared
@@ -49,4 +48,3 @@ variadic.sil, line 50, column 7: SIL consistency error: variadic parameter is no
 variadic.sil, line 40, column 7: SIL consistency error: variadic parameter is not in penultimate position in trait function T.bad
 variadic.sil, line 28, column 7: SIL consistency error: variadic parameter is not in penultimate position in function with_generics_bad which has a reified generics parameter
 variadic.sil, line 18, column 7: SIL consistency error: variadic parameter is not in last position in function f3
-variadic.sil, line 10, column 8: SIL consistency error: function f2 which can be called with 1 arguments is not declared