[flow] add more SingletonNumT special-casing

Summary: This diff extends the work of D68337708, by filling in more cases that rely on the unsound `SingletonNumT ~> NumT_UNSOUND` coercion. Effectively, in places where we match against `NumT_UNSOUND`, we almost certainly want to match against `SingletonNUmT` as well. Changelog: [internal] Reviewed By: SamChou19815 Differential Revision: D68425896 fbshipit-source-id: 8be830491b9b78b9c2055c769f1791c031212a7b
facebook · Jan 23, 2025 · 10559ca · 10559ca
1 parent 1e83204
commit 10559ca
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Showing 5 changed files with 54 additions and 24 deletions.
diff --git a/src/typing/flow_js.ml b/src/typing/flow_js.ml
@@ -3748,7 +3748,7 @@ struct
           rec_flow cx trace (key, ElemT (use_op, reason_lookup, l, action))
         (* If we are accessing `Iterable<T>` with a number, and have `access_iterables = true`,
            then output `T`. *)
-        | ( DefT (_, (NumGeneralT _ | NumT_UNSOUND _)),
+        | ( DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _)),
             ElemT
               ( use_op,
                 _,
@@ -3799,7 +3799,7 @@ struct
             | None -> value
           in
           perform_elem_action cx trace ~use_op ~restrict_deletes:false reason_op arr value action
-        | ( DefT (_, (NumGeneralT _ | NumT_UNSOUND _)),
+        | ( DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _)),
             ElemT (use_op, reason, (DefT (reason_tup, ArrT arrtype) as arr), action)
           ) ->
           let (write_action, read_action, never_union_void_on_computed_prop_access) =
@@ -5143,7 +5143,8 @@ struct
         (***********************)
         (* Number library call *)
         (***********************)
-        | (DefT (reason, (NumGeneralT _ | NumT_UNSOUND _)), u) when primitive_promoting_use_t u ->
+        | (DefT (reason, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _)), u)
+          when primitive_promoting_use_t u ->
           rec_flow cx trace (get_builtin_type cx ~trace reason "Number", u)
         (***********************)
         (* Boolean library call *)
@@ -5255,8 +5256,9 @@ struct
                  suggestion = None;
                }
             )
-        | (DefT (reason, NumT_UNSOUND (_, (value, _))), WriteComputedObjPropCheckT { reason_key; _ })
-          ->
+        | ( DefT (reason, (NumT_UNSOUND (_, (value, _)) | SingletonNumT (value, _))),
+            WriteComputedObjPropCheckT { reason_key; _ }
+          ) ->
           let kind = Flow_intermediate_error_types.InvalidObjKey.kind_of_num_value value in
           add_output cx (Error_message.EObjectComputedPropertyAssign (reason, reason_key, kind))
         | (_, WriteComputedObjPropCheckT { reason = _; reason_key; _ }) ->

diff --git a/src/typing/flow_js_utils.ml b/src/typing/flow_js_utils.ml
@@ -285,7 +285,7 @@ let ground_subtype = function
   | (_, UseT (_, OpenT _)) ->
     false
   | (UnionT _, _) -> false
-  | ( DefT (_, (NumGeneralT _ | NumT_UNSOUND _)),
+  | ( DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _)),
       UseT (_, DefT (_, (NumGeneralT _ | NumT_UNSOUND _)))
     )
   | ( DefT (_, (StrGeneralT _ | StrT_UNSOUND _ | SingletonStrT _)),
@@ -2410,8 +2410,9 @@ module GetPropT_kit (F : Get_prop_helper_sig) = struct
           let loc = loc_of_t elem_t in
           add_output cx Error_message.(EInternal (loc, PropRefComputedLiteral));
           F.error_type cx trace reason_op
-        | GenericT { bound = DefT (_, NumT_UNSOUND (_, (value, _))); _ }
-        | DefT (_, NumT_UNSOUND (_, (value, _))) ->
+        | GenericT
+            { bound = DefT (_, (NumT_UNSOUND (_, (value, _)) | SingletonNumT (value, _))); _ }
+        | DefT (_, (NumT_UNSOUND (_, (value, _)) | SingletonNumT (value, _))) ->
           let reason_prop = reason_of_t elem_t in
           let kind = Flow_intermediate_error_types.InvalidObjKey.kind_of_num_value value in
           add_output cx (Error_message.EObjectComputedPropertyAccess (reason_op, reason_prop, kind));
@@ -2460,7 +2461,8 @@ let array_elem_check
   in
   let (can_write_tuple, value, use_op) =
     match l with
-    | DefT (index_reason, NumT_UNSOUND (_, (float_value, _))) -> begin
+    | DefT (index_reason, (NumT_UNSOUND (_, (float_value, _)) | SingletonNumT (float_value, _))) ->
+    begin
       match elements with
       | None -> (false, elem_t, use_op)
       | Some elements ->
@@ -2559,8 +2561,13 @@ let propref_for_elem_t = function
     let reason = replace_desc_reason (RProperty (Some name)) reason in
     mk_named_prop ~reason ~from_indexed_access:true name
   | OpaqueT (reason_num, { super_t = Some (DefT (_, SingletonNumT (value, raw))); _ })
-  | GenericT { bound = DefT (_, NumT_UNSOUND (_, (value, raw))); reason = reason_num; _ }
-  | DefT (reason_num, NumT_UNSOUND (_, (value, raw)))
+  | GenericT
+      {
+        bound = DefT (_, (NumT_UNSOUND (_, (value, raw)) | SingletonNumT (value, raw)));
+        reason = reason_num;
+        _;
+      }
+  | DefT (reason_num, (NumT_UNSOUND (_, (value, raw)) | SingletonNumT (value, raw)))
     when Js_number.is_float_safe_integer value ->
     let reason = replace_desc_reason (RProperty (Some (OrdinaryName raw))) reason_num in
     let name = OrdinaryName (Dtoa.ecma_string_of_float value) in
@@ -2701,9 +2708,9 @@ let flow_unary_arith cx l reason kind =
     add_output cx (Error_message.EBigIntNumCoerce reason_bigint);
     AnyT.error reason
   | (Plus, _) -> NumModuleT.why reason
-  | (BitNot, DefT (_, (NumGeneralT _ | NumT_UNSOUND _))) -> NumModuleT.why reason
+  | (BitNot, DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _))) -> NumModuleT.why reason
   | (BitNot, DefT (_, (BigIntGeneralT _ | BigIntT_UNSOUND _))) -> BigIntModuleT.why reason
-  | (Update, DefT (_, (NumGeneralT _ | NumT_UNSOUND _))) -> NumModuleT.why reason
+  | (Update, DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _))) -> NumModuleT.why reason
   | (Update, DefT (_, (BigIntGeneralT _ | BigIntT_UNSOUND _))) -> BigIntModuleT.why reason
   | (_, AnyT (_, src)) ->
     let src = any_mod_src_keep_placeholder Untyped src in
@@ -2727,7 +2734,10 @@ let flow_arith cx reason l r kind =
   | (_, _, DefT (_, EmptyT)) ->
     EmptyT.why reason
   (* num <> num *)
-  | (_, DefT (_, (NumGeneralT _ | NumT_UNSOUND _)), DefT (_, (NumGeneralT _ | NumT_UNSOUND _))) ->
+  | ( _,
+      DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _)),
+      DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _))
+    ) ->
     NumModuleT.why reason
   | (RShift3, DefT (reason, (BigIntGeneralT _ | BigIntT_UNSOUND _)), _) ->
     add_output cx (Error_message.EBigIntRShift3 reason);
@@ -2742,9 +2752,14 @@ let flow_arith cx reason l r kind =
   (* str + num *)
   (* num + str *)
   | (Plus, DefT (_, (StrGeneralT _ | StrT_UNSOUND _)), DefT (_, (StrGeneralT _ | StrT_UNSOUND _)))
-  | (Plus, DefT (_, (StrGeneralT _ | StrT_UNSOUND _)), DefT (_, (NumGeneralT _ | NumT_UNSOUND _)))
-  | (Plus, DefT (_, (NumGeneralT _ | NumT_UNSOUND _)), DefT (_, (StrGeneralT _ | StrT_UNSOUND _)))
-    ->
+  | ( Plus,
+      DefT (_, (StrGeneralT _ | StrT_UNSOUND _)),
+      DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _))
+    )
+  | ( Plus,
+      DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _)),
+      DefT (_, (StrGeneralT _ | StrT_UNSOUND _))
+    ) ->
     StrModuleT.why reason
   | _ ->
     add_output

diff --git a/src/typing/merge_js.ml b/src/typing/merge_js.ml
@@ -114,7 +114,8 @@ let detect_sketchy_null_checks cx tast =
             | DefT (_, StrT_UNSOUND _) ->
               { exists_check with string_loc = t_loc }
             | DefT (_, NumGeneralT _)
-            | DefT (_, NumT_UNSOUND _) ->
+            | DefT (_, NumT_UNSOUND _)
+            | DefT (_, SingletonNumT _) ->
               { exists_check with number_loc = t_loc }
             | DefT (_, (BigIntGeneralT _ | BigIntT_UNSOUND _)) ->
               { exists_check with bigint_loc = t_loc }
@@ -161,14 +162,22 @@ let detect_sketchy_null_checks cx tast =
                 ( _,
                   EnumValueT
                     (ConcreteEnum
-                      { representation_t = DefT (_, (NumGeneralT _ | NumT_UNSOUND _)); _ }
+                      {
+                        representation_t =
+                          DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _));
+                        _;
+                      }
                       )
                 )
             | DefT
                 ( _,
                   EnumValueT
                     (AbstractEnum
-                      { representation_t = DefT (_, (NumGeneralT _ | NumT_UNSOUND _)); _ }
+                      {
+                        representation_t =
+                          DefT (_, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _));
+                        _;
+                      }
                       )
                 ) ->
               { exists_check with enum_number_loc = t_loc }

diff --git a/src/typing/subtyping_kit.ml b/src/typing/subtyping_kit.ml
@@ -993,7 +993,9 @@ module Make (Flow : INPUT) : OUTPUT = struct
       add_output
         cx
         (Error_message.EExpectedStringLit { reason_lower = rl; reason_upper = ru; use_op })
-    | (DefT (rl, NumT_UNSOUND (_, (actual, _))), DefT (ru, SingletonNumT (expected, _))) ->
+    | ( DefT (rl, (NumT_UNSOUND (_, (actual, _)) | SingletonNumT (actual, _))),
+        DefT (ru, SingletonNumT (expected, _))
+      ) ->
       if expected = actual then
         ()
       else
@@ -2265,7 +2267,7 @@ module Make (Flow : INPUT) : OUTPUT = struct
       add_output
         cx
         (Error_message.EPrimitiveAsInterface { use_op; reason; interface_reason; kind = `Boolean })
-    | ( DefT (reason, (NumGeneralT _ | NumT_UNSOUND _)),
+    | ( DefT (reason, (NumGeneralT _ | NumT_UNSOUND _ | SingletonNumT _)),
         DefT (interface_reason, InstanceT { inst = { inst_kind = InterfaceKind _; _ }; _ })
       ) ->
       add_output
@@ -2446,7 +2448,8 @@ module Make (Flow : INPUT) : OUTPUT = struct
         | DefT (_, BoolT_UNSOUND _) ->
           Some "boolean"
         | DefT (_, NumGeneralT _)
-        | DefT (_, NumT_UNSOUND _) ->
+        | DefT (_, NumT_UNSOUND _)
+        | DefT (_, SingletonNumT _) ->
           Some "number"
         | DefT (_, StrGeneralT _)
         | DefT (_, SingletonStrT _)

diff --git a/src/typing/type_operation_utils.ml b/src/typing/type_operation_utils.ml
@@ -711,7 +711,8 @@ module TypeAssertions = struct
       | DefT (_, SingletonStrT _) ->
         ()
       | DefT (_, NumGeneralT _)
-      | DefT (_, NumT_UNSOUND _) ->
+      | DefT (_, NumT_UNSOUND _)
+      | DefT (_, SingletonNumT _) ->
         ()
       | l -> add_output cx (Error_message.EBinaryInLHS (reason_of_t l))
     )