diff --git a/src/arr/compiler/type-check.arr b/src/arr/compiler/type-check.arr
index 5e57549f7e..67cf8ec430 100644
--- a/src/arr/compiler/type-check.arr
+++ b/src/arr/compiler/type-check.arr
@@ -1858,8 +1858,8 @@ end
 
 fun synthesis-extend(update-loc :: Loc, obj :: Expr, obj-type :: Type, fields :: List<A.Member>, context :: Context) -> TypingResult:
   collect-members(fields, false, context).typing-bind(lam(new-members, shadow context):
-    instantiate-object-type(obj-type, context).typing-bind(lam(shadow obj-type, shadow context):
-      cases(Type) obj-type:
+    instantiate-object-type(obj-type, context).typing-bind(lam(instantiated-obj-type, shadow context):
+      cases(Type) instantiated-obj-type:
         | t-record(t-fields, _, inferred) =>
           final-fields = new-members.fold-keys(lam(key, final-fields):
             final-fields.set(key, new-members.get-value(key))
@@ -1868,7 +1868,10 @@ fun synthesis-extend(update-loc :: Loc, obj :: Expr, obj-type :: Type, fields ::
         | t-existential(_, l, _) =>
           typing-error([list: C.unable-to-infer(l)])
         | else =>
-          typing-error([list: C.incorrect-type-expression(tostring(obj-type), obj-type.l, "an object type", update-loc, obj)])
+          shadow context = new-members.fold-keys(lam(key, shadow context):
+            context.add-field-constraint(instantiated-obj-type, key, new-members.get-value(key))
+          end, context)
+          typing-result(A.s-extend(update-loc, obj, fields), obj-type, context)
       end
     end)
   end)
@@ -1876,13 +1879,13 @@ end
 
 fun synthesis-update(update-loc :: Loc, obj :: Expr, obj-type :: Type, fields :: List<A.Member>, context :: Context) -> TypingResult:
   collect-members(fields, false, context).typing-bind(lam(new-members, shadow context):
-    instantiate-object-type(obj-type, context).typing-bind(lam(shadow obj-type, shadow context):
+    instantiate-object-type(obj-type, context).typing-bind(lam(instantiated-obj-type, shadow context):
       cases(Type) obj-type:
         | t-record(t-fields, _, inferred) =>
           foldr-fold-result(lam(key, shadow context, final-fields):
             cases(Option<Type>) t-fields.get(key):
               | none =>
-                fold-errors([list: C.object-missing-field(key, tostring(obj-type), obj-type.l, update-loc)])
+                fold-errors([list: C.object-missing-field(key, tostring(instantiated-obj-type), instantiated-obj-type.l, update-loc)])
               | some(old-type) =>
                 cases(Type) old-type:
                   | t-ref(onto, l, ref-inferred) =>
@@ -1898,7 +1901,11 @@ fun synthesis-update(update-loc :: Loc, obj :: Expr, obj-type :: Type, fields ::
         | t-existential(_, l, _) =>
           typing-error([list: C.unable-to-infer(l)])
         | else =>
-          typing-error([list: C.incorrect-type-expression(tostring(obj-type), obj-type.l, "an object type", update-loc, obj)])
+          shadow context = new-members.fold-keys(lam(key, shadow context):
+            member-type = new-members.get-value(key)
+            context.add-field-constraint(instantiated-obj-type, key, t-ref(member-type, member-type.l, false))
+          end, context)
+          typing-result(A.s-update(update-loc, obj, fields), obj-type, context)
       end
     end)
   end)
diff --git a/tests/type-check/bad/data-as-object-extend-missing.arr b/tests/type-check/bad/data-as-object-extend-missing.arr
new file mode 100644
index 0000000000..bcfcbd4b69
--- /dev/null
+++ b/tests/type-check/bad/data-as-object-extend-missing.arr
@@ -0,0 +1,6 @@
+data Foo:
+  | bar(a :: Number, ref b :: String)
+end
+
+# bar(1, "a") does not have a field c
+bar(1, "a").{c: "a"}
\ No newline at end of file
diff --git a/tests/type-check/bad/data-as-object-extend-ref.arr b/tests/type-check/bad/data-as-object-extend-ref.arr
new file mode 100644
index 0000000000..d8ac0068ce
--- /dev/null
+++ b/tests/type-check/bad/data-as-object-extend-ref.arr
@@ -0,0 +1,6 @@
+data Foo:
+  | bar(a :: Number, ref b :: String)
+end
+
+# bar(1, "a").b is a ref String while "a" is a String
+bar(1, "a").{b: "a"}
\ No newline at end of file
diff --git a/tests/type-check/bad/data-as-object-extend-wrong-type.arr b/tests/type-check/bad/data-as-object-extend-wrong-type.arr
new file mode 100644
index 0000000000..f7e2610c87
--- /dev/null
+++ b/tests/type-check/bad/data-as-object-extend-wrong-type.arr
@@ -0,0 +1,6 @@
+data Foo:
+  | bar(a :: Number, ref b :: String)
+end
+
+# bar(1, "a").a has type Number not String
+bar(1, "a").{a: "b"}
\ No newline at end of file
diff --git a/tests/type-check/bad/data-as-object-update-missing.arr b/tests/type-check/bad/data-as-object-update-missing.arr
new file mode 100644
index 0000000000..60e96538b5
--- /dev/null
+++ b/tests/type-check/bad/data-as-object-update-missing.arr
@@ -0,0 +1,6 @@
+data Foo:
+  | bar(a :: Number, ref b :: String)
+end
+
+# bar(1, "a") does not have a field c
+bar(1, "a")!{c: 3}
\ No newline at end of file
diff --git a/tests/type-check/bad/data-as-object-update-non-ref.arr b/tests/type-check/bad/data-as-object-update-non-ref.arr
new file mode 100644
index 0000000000..d21993beca
--- /dev/null
+++ b/tests/type-check/bad/data-as-object-update-non-ref.arr
@@ -0,0 +1,6 @@
+data Foo:
+  | bar(a :: Number, ref b :: String)
+end
+
+# bar(1, "a").a is a String but update is for refs 
+bar(1, "a")!{a: 3}
\ No newline at end of file
diff --git a/tests/type-check/bad/data-as-object-update-wrong.arr b/tests/type-check/bad/data-as-object-update-wrong.arr
new file mode 100644
index 0000000000..d8c6f9eb89
--- /dev/null
+++ b/tests/type-check/bad/data-as-object-update-wrong.arr
@@ -0,0 +1,6 @@
+data Foo:
+  | bar(a :: Number, ref b :: String)
+end
+
+# bar(1, "a").b has type String not Number
+bar(1, "a")!{b: 3}
\ No newline at end of file
diff --git a/tests/type-check/good/data-as-object.arr b/tests/type-check/good/data-as-object.arr
new file mode 100644
index 0000000000..59c86c67c9
--- /dev/null
+++ b/tests/type-check/good/data-as-object.arr
@@ -0,0 +1,6 @@
+data Foo:
+  | bar(a :: Number, ref b :: String)
+end
+
+bar(1, "a").{a: 3}
+bar(1, "b")!{b: "a"}
\ No newline at end of file