binary operator overrides

Summary:
this diff updates some of the logic from previous diffs to account for operator overrides like we do for comparison operators

there is a unit test for comparison op overrides here:
https://www.internalfb.com/code/fbsource/[4898bc565af6456c52fb093d68004b70c3b1d49d]/fbcode/tools/pyre/source/ast/test/expressionTest.ml?lines=391

which I'll probably add for the binops in a later diff but it won't work now because we don't generate this AST node during parsing.

Reviewed By: arthaud

Differential Revision: D57627670

fbshipit-source-id: 804d3135e336f6a2a55ed337921609fbe0c9eb4d

source/analysis/typeCheck.ml

@@ -1896,9 +1896,11 @@ module State (Context : Context) = struct
                 in
                 { resolution; resolved = Type.Any; errors; resolved_annotation = None; base = None }
             ))
-    (* TODO: T101299882 *)
-    | BinaryOperator _ ->
-        { resolution; resolved = Type.Any; errors = []; resolved_annotation = None; base = None }
+    | BinaryOperator operator ->
+        let resolved =
+          forward_expression ~resolution (BinaryOperator.override ~location operator)
+        in
+        { resolved with errors = resolved.errors }
     | BooleanOperator { BooleanOperator.left; operator; right } -> (
         let {
           Resolved.resolution = resolution_left;

source/ast/expression.ml

@@ -397,6 +397,8 @@ and BinaryOperator : sig
   val pp_binary_operator : Format.formatter -> operator -> unit
 
   val location_insensitive_compare : t -> t -> int
+
+  val override : location:Location.t -> t -> Expression.t
 end = struct
   type operator =
     | Add
@@ -448,6 +450,38 @@ end = struct
         match [%compare: operator] left.operator right.operator with
         | x when not (Int.equal x 0) -> x
         | _ -> Expression.location_insensitive_compare left.right right.right)
+
+
+  let override ~location { left; operator; right } =
+    let operator =
+      match operator with
+      | Add -> "__add__"
+      | Sub -> "__sub__"
+      | Mult -> "__mul__"
+      | MatMult -> "__matmul__"
+      | Div -> "__truediv__"
+      | Mod -> "__mod__"
+      | Pow -> "__pow__"
+      | LShift -> "__lshift__"
+      | RShift -> "__rshift__"
+      | BitOr -> "__or__"
+      | BitXor -> "__xor__"
+      | BitAnd -> "__and__"
+      | FloorDiv -> "__floordiv__"
+    in
+    let arguments = [{ Call.Argument.name = None; value = right }] in
+    Expression.Call
+      {
+        Call.callee =
+          {
+            Node.location;
+            value =
+              Expression.Name
+                (Name.Attribute { Name.Attribute.base = left; attribute = operator; special = true });
+          };
+        arguments;
+      }
+    |> Node.create ~location
 end
 
 and Comprehension : sig

source/ast/expression.mli

@@ -146,6 +146,8 @@ and BinaryOperator : sig
   val pp_binary_operator : Format.formatter -> operator -> unit
 
   val location_insensitive_compare : t -> t -> int
+
+  val override : location:Location.t -> t -> Expression.t
 end
 
 and Comprehension : sig

source/interprocedural/callGraph.ml

@@ -2570,6 +2570,7 @@ struct
             >>| ExpressionCallees.from_identifier
             >>| register_targets ~expression_identifier:identifier
             |> ignore
+        | Expression.BinaryOperator _ -> failwith "T101299882"
         | Expression.ComparisonOperator comparison -> (
             match ComparisonOperator.override ~location comparison with
             | Some { Node.value = Expression.Call call; _ } ->