[self-in-block] Do not report strongSelf Not Checked when passed to a…

… nullable position

Summary: Sometimes it's needed to do those calls even if `strongSelf` is nil.

Reviewed By: ngorogiannis

Differential Revision:
D66109087

Privacy Context Container: L1208441

fbshipit-source-id: 11129312a0a088c3874ac7d65287cacdda5501b4

infer/src/checkers/SelfInBlock.ml

@@ -372,6 +372,26 @@ module TransferFunctions = struct
         false
 
 
+  let clear_unchecked_use_args attributes args (astate : Domain.t) =
+    let clear_unchecked_use_non_nullable_arg astate (arg, _) annotation =
+      match arg with
+      | Exp.Var id when Annotations.ia_is_nullable annotation ->
+          Domain.clear_unchecked_use id astate
+      | _ ->
+          astate
+    in
+    let args =
+      if is_objc_instance (Some attributes) then match args with _ :: rest -> rest | [] -> []
+      else args
+    in
+    let annotations = List.map attributes.ProcAttributes.formals ~f:trd3 in
+    match List.fold2 ~f:clear_unchecked_use_non_nullable_arg ~init:astate args annotations with
+    | List.Or_unequal_lengths.Ok astate ->
+        astate
+    | List.Or_unequal_lengths.Unequal_lengths ->
+        astate
+
+
   let exec_instr (astate : Domain.t) {IntraproceduralAnalysis.proc_desc} _cfg_node _
       (instr : Sil.instr) =
     let attributes = Procdesc.get_attributes proc_desc in
@@ -400,18 +420,23 @@ module TransferFunctions = struct
       when Exp.is_null_literal e (* if !(strongSef != nil) *) ->
         Domain.clear_unchecked_use id astate
     | Call (_, Exp.Const (Const.Cfun callee_pn), args, _, cf) ->
+        let attributes_opt = Attributes.load callee_pn in
         let fst =
           if cf.CallFlags.cf_virtual then List.hd args
-          else
-            let attributes_opt = Attributes.load callee_pn in
-            if is_objc_instance attributes_opt then List.hd args else None
+          else if is_objc_instance attributes_opt then List.hd args
+          else None
         in
         let astate =
           Option.value_map
             ~f:(fun (arg, _) ->
               match arg with Exp.Var id -> Domain.clear_unchecked_use id astate | _ -> astate )
             ~default:astate fst
         in
+        let astate =
+          Option.value_map
+            ~f:(fun attributes -> clear_unchecked_use_args attributes args astate)
+            attributes_opt ~default:astate
+        in
         List.fold ~init:astate ~f:(fun astate (exp, _) -> Domain.process_exp exp astate) args
     | _ ->
         astate

infer/tests/codetoanalyze/objc/self-in-block/StrongSelf.m

@@ -131,7 +131,7 @@ - (void)strongSelfCheck2_bad {
   };
 }
 
-- (void)strongSelfCheck6_bad {
+- (void)strongSelfCheck6_good {
   __weak __typeof(self) weakSelf = self;
   int (^my_block)(BOOL) = ^(BOOL isTapped) {
     __strong __typeof(weakSelf) strongSelf = weakSelf;

infer/tests/codetoanalyze/objc/self-in-block/issues.exp

@@ -12,7 +12,6 @@ codetoanalyze/objc/self-in-block/StrongSelf.m, objc_block_StrongSelf.m:78, 1, CA
 codetoanalyze/objc/self-in-block/StrongSelf.m, objc_block_StrongSelf.m:97, 2, STRONG_SELF_NOT_CHECKED, no_bucket, ERROR, [Using &strongSelf]
 codetoanalyze/objc/self-in-block/StrongSelf.m, objc_block_StrongSelf.m:106, 6, STRONG_SELF_NOT_CHECKED, no_bucket, ERROR, [Using &strongSelf,Using &strongSelf,Using &strongSelf,Using &strongSelf], +""=>"\n if (!strongSelf) { return; }"@112:1
 codetoanalyze/objc/self-in-block/StrongSelf.m, objc_block_StrongSelf.m:121, 6, STRONG_SELF_NOT_CHECKED, no_bucket, ERROR, [Using &strongSelf,Using &strongSelf,Using &strongSelf]
-codetoanalyze/objc/self-in-block/StrongSelf.m, objc_block_StrongSelf.m:136, 2, STRONG_SELF_NOT_CHECKED, no_bucket, ERROR, [Using &strongSelf]
 codetoanalyze/objc/self-in-block/StrongSelf.m, objc_block_StrongSelf.m:158, 2, STRONG_SELF_NOT_CHECKED, no_bucket, ERROR, [Using &strongSelf,Using &strongSelf]
 codetoanalyze/objc/self-in-block/StrongSelf.m, objc_block_StrongSelf.m:170, 2, STRONG_SELF_NOT_CHECKED, no_bucket, ERROR, [Using &strongSelf,Using &strongSelf]
 codetoanalyze/objc/self-in-block/StrongSelf.m, objc_block_StrongSelf.m:179, 3, STRONG_SELF_NOT_CHECKED, no_bucket, ERROR, [Using &strongSelf,Using &strongSelf]