diff --git a/lib/rbs/test/type_check.rb b/lib/rbs/test/type_check.rb
index 3e8f9d3ba..243e5b4ba 100644
--- a/lib/rbs/test/type_check.rb
+++ b/lib/rbs/test/type_check.rb
@@ -364,6 +364,7 @@ def value(val, type)
           value(val, builder.expand_alias2(type.name.absolute!, type.args))
         when Types::Tuple
           Test.call(val, IS_AP, ::Array) &&
+            type.types.length == val.length &&
             type.types.map.with_index {|ty, index| value(val[index], ty) }.all?
         when Types::Record
           Test::call(val, IS_AP, ::Hash) &&
diff --git a/stdlib/objspace/0/objspace.rbs b/stdlib/objspace/0/objspace.rbs
index e51d42fd4..cdd89a3cb 100644
--- a/stdlib/objspace/0/objspace.rbs
+++ b/stdlib/objspace/0/objspace.rbs
@@ -411,7 +411,7 @@ module ObjectSpace
   #     ObjectSpace.reachable_objects_from(1)
   #     #=> nil # 1 is not markable (heap managed) object
   #
-  def self?.reachable_objects_from: (untyped) -> ([ untyped ] | nil)
+  def self?.reachable_objects_from: (untyped) -> (Array[untyped] | nil)
 
   # <!--
   #   rdoc-file=ext/objspace/objspace.c
diff --git a/test/rbs/test/type_check_test.rb b/test/rbs/test/type_check_test.rb
index 71fc93231..014dd39c0 100644
--- a/test/rbs/test/type_check_test.rb
+++ b/test/rbs/test/type_check_test.rb
@@ -67,6 +67,10 @@ def to_int: () -> Integer
         refute typecheck.value(nil, parse_type("bool"))
         refute typecheck.value("", parse_type("bool"))
         refute typecheck.value(BasicObject.new, parse_type("bool"))
+
+        assert typecheck.value([1], parse_type("[Integer]"))
+        refute typecheck.value([], parse_type("[Integer]"))
+        refute typecheck.value([1, 2], parse_type("[Integer]"))
       end
     end
   end
diff --git a/test/stdlib/ObjectSpace_test.rb b/test/stdlib/ObjectSpace_test.rb
index 092a94feb..bfbaab3e2 100644
--- a/test/stdlib/ObjectSpace_test.rb
+++ b/test/stdlib/ObjectSpace_test.rb
@@ -181,9 +181,9 @@ def test_memsize_of_all
   end
 
   def test_reachable_objects_from
-    assert_send_type "(untyped) -> [untyped]",
+    assert_send_type "(untyped) -> Array[untyped]",
       ObjectSpace, :reachable_objects_from, "dummy"
-    assert_send_type "(untyped) -> [untyped]",
+    assert_send_type "(untyped) -> Array[untyped]",
       ObjectSpace, :reachable_objects_from, ["dummy", "dummy2"]
     assert_send_type "(untyped) -> nil",
       ObjectSpace, :reachable_objects_from, nil