Fix exact object indexer issue

src/typing/flow_js.ml

@@ -6741,7 +6741,7 @@ and flow_obj_to_obj cx trace ~use_op (lreason, l_obj) (ureason, u_obj) =
         (Field (None, lv, lpolarity), Field (None, uv, upolarity))
     | _ -> ());
 
-  if rflags.exact && rflags.sealed = Sealed && not (is_literal_object_reason ureason)
+  if udict = None && rflags.exact && rflags.sealed = Sealed && not (is_literal_object_reason ureason)
   then (
     iter_real_props cx lflds (fun ~is_sentinel s _ ->
       if not (Context.has_prop cx uflds s)

tests/exact/exact.exp

@@ -164,6 +164,55 @@ References:
                                                            ^^^^^^^^^^ [1]
 
 
+Error --------------------------------------------------------------------------------------------- exact_indexer.js:4:2
+
+Cannot cast object literal to object type because number [1] is incompatible with string [2] in property `a`.
+
+   exact_indexer.js:4:2
+   4| ({ a: 123 }: {| ['a']: string |}); // error
+       ^^^^^^^^^^
+
+References:
+   exact_indexer.js:4:7
+   4| ({ a: 123 }: {| ['a']: string |}); // error
+            ^^^ [1]
+   exact_indexer.js:4:24
+   4| ({ a: 123 }: {| ['a']: string |}); // error
+                             ^^^^^^ [2]
+
+
+Error --------------------------------------------------------------------------------------------- exact_indexer.js:5:2
+
+Cannot cast object literal to object type because string `a` [1] is incompatible with string literal `b` [2] in the
+indexer property's key.
+
+   exact_indexer.js:5:2
+   5| ({ a: 123 }: {| ['b']: number |}); // error
+       ^^^^^^^^^^ [1]
+
+References:
+   exact_indexer.js:5:18
+   5| ({ a: 123 }: {| ['b']: number |}); // error
+                       ^^^ [2]
+
+
+Error --------------------------------------------------------------------------------------------- exact_indexer.js:7:2
+
+Cannot cast object literal to object type because number [1] is incompatible with string [2] in property `a`.
+
+   exact_indexer.js:7:2
+   7| ({ a: 123 }: {| [string]: string |}); // error
+       ^^^^^^^^^^
+
+References:
+   exact_indexer.js:7:7
+   7| ({ a: 123 }: {| [string]: string |}); // error
+            ^^^ [1]
+   exact_indexer.js:7:27
+   7| ({ a: 123 }: {| [string]: string |}); // error
+                                ^^^^^^ [2]
+
+
 Error -------------------------------------------------------------------------------------------------- objmap.js:11:32
 
 Cannot assign object literal to `doesError` because number [1] is incompatible with number literal `2` [2] in property
@@ -333,4 +382,4 @@ References:
 
 
 
-Found 20 errors
+Found 23 errors

tests/exact/exact_indexer.js

@@ -0,0 +1,7 @@
+// @flow
+
+({ a: 123 }: {| ['a']: number |}); // OK
+({ a: 123 }: {| ['a']: string |}); // error
+({ a: 123 }: {| ['b']: number |}); // error
+({ a: 123 }: {| [string]: number |}); // OK
+({ a: 123 }: {| [string]: string |}); // error