2 files changed, 4 insertions, 33 deletions
diff --git a/ext/json/lib/json/common.rb b/ext/json/lib/json/common.rb
index b2f11afe55..c9f6d7505b 100644
--- a/ext/json/lib/json/common.rb
+++ b/ext/json/lib/json/common.rb
@@ -74,16 +74,6 @@ module JSON
       $VERBOSE = old
     end
 
-    def create_fast_state
-      State.new(
-        :indent         => '',
-        :space          => '',
-        :object_nl      => "",
-        :array_nl       => "",
-        :max_nesting    => false
-      )
-    end
-
     def create_pretty_state
       State.new(
         :indent         => '  ',
@@ -368,12 +358,12 @@ module JSON
   #   # Raises SystemStackError (stack level too deep):
   #   JSON.fast_generate(a)
   def fast_generate(obj, opts = nil)
-    if State === opts
-      state = opts
+    if RUBY_VERSION >= "3.0"
+      warn "JSON.fast_generate is deprecated and will be removed in json 3.0.0, just use JSON.generate", uplevel: 1, category: :deprecated
     else
-      state = JSON.create_fast_state.configure(opts)
+      warn "JSON.fast_generate is deprecated and will be removed in json 3.0.0, just use JSON.generate", uplevel: 1
     end
-    state.generate(obj)
+    generate(obj, opts)
   end
 
   # :call-seq:
diff --git a/test/json/json_generator_test.rb b/test/json/json_generator_test.rb
index f0dec452f3..64636c12c2 100755
--- a/test/json/json_generator_test.rb
+++ b/test/json/json_generator_test.rb
@@ -237,25 +237,6 @@ class JSONGeneratorTest < Test::Unit::TestCase
     }.sort_by { |n,| n.to_s }, state.to_h.sort_by { |n,| n.to_s })
   end
 
-  def test_fast_state
-    state = JSON.create_fast_state
-    assert_equal({
-      :allow_nan             => false,
-      :array_nl              => "",
-      :as_json               => false,
-      :ascii_only            => false,
-      :buffer_initial_length => 1024,
-      :depth                 => 0,
-      :script_safe           => false,
-      :strict                => false,
-      :indent                => "",
-      :max_nesting           => 0,
-      :object_nl             => "",
-      :space                 => "",
-      :space_before          => "",
-    }.sort_by { |n,| n.to_s }, state.to_h.sort_by { |n,| n.to_s })
-  end
-
   def test_allow_nan
     error = assert_raise(GeneratorError) { generate([JSON::NaN]) }
     assert_same JSON::NaN, error.invalid_object