diff --git a/test/ruby/test_keyword.rb b/test/ruby/test_keyword.rb
index 576f219dac295d..cfc3dc11da511f 100644
--- a/test/ruby/test_keyword.rb
+++ b/test/ruby/test_keyword.rb
@@ -4273,6 +4273,31 @@ def test_many_kwargs
     assert_equal(:ok, many_kwargs(e0: :ok)[i], "#{i}: e0"); i+=1
   end
 
+  def test_many_kwargs_with_integer_refinement
+    assert_separately([], <<~'RUBY')
+      module Ref
+        refine Integer do
+          def ==(other) super; end
+        end
+      end
+
+      # 257 indices guarantee a collision in the 8-bit hint of a small Hash.
+      # Keep both indices above the keyword bitmask limit.
+      indices = (32...289).to_a
+      a, b = indices.combination(2).find { |x, y| (x.hash & 0xff) == (y.hash & 0xff) }
+      expected = (0...289).to_a
+      expected[a] = {}
+      expected[b] = {}
+      params = expected.each_with_index.map { |value, i| "k#{i}: #{value.inspect}" }
+      eval "def victim(#{params.join(', ')}) [#{expected.each_index.map { |i| "k#{i}" }.join(', ')}]; end"
+
+      assert_equal(expected, victim, '[Bug #22335]')
+      assert_equal(expected, victim(k0: 0), '[Bug #22335]')
+      kwargs = {k0: 0}
+      assert_equal(expected, victim(**kwargs), '[Bug #22335]')
+    RUBY
+  end
+
   def test_splat_empty_hash_with_block_passing
     assert_valid_syntax("bug15087(**{}, &nil)")
   end
diff --git a/vm_args.c b/vm_args.c
index 2610d99c229b5e..33a41c6445737c 100644
--- a/vm_args.c
+++ b/vm_args.c
@@ -320,6 +320,37 @@ args_setup_kw_parameters_lookup(const ID key, VALUE *ptr, const VALUE *const pas
     return FALSE;
 }
 
+static inline void
+args_setup_kw_parameters_not_found(const VALUE *default_values, VALUE *locals, int i, int di,
+                                   int *unspecified_bits, VALUE *unspecified_bits_value)
+{
+    if (UNDEF_P(default_values[di])) {
+        locals[i] = Qnil;
+
+        if (LIKELY(i < VM_KW_SPECIFIED_BITS_MAX)) {
+            *unspecified_bits |= 0x01 << di;
+        }
+        else {
+            VALUE bits_value = *unspecified_bits_value;
+            if (NIL_P(bits_value)) {
+                /* fixnum -> hash */
+                int bits = *unspecified_bits;
+                *unspecified_bits_value = bits_value = rb_ident_hash_new();
+
+                for (int j=0; j<VM_KW_SPECIFIED_BITS_MAX; j++) {
+                    if (bits & (0x01 << j)) {
+                        rb_hash_aset(bits_value, INT2FIX(j), Qtrue);
+                    }
+                }
+            }
+            rb_hash_aset(bits_value, INT2FIX(di), Qtrue);
+        }
+    }
+    else {
+        locals[i] = default_values[di];
+    }
+}
+
 static void
 args_setup_kw_parameters(rb_execution_context_t *const ec, const rb_iseq_t *const iseq, const rb_callable_method_entry_t *cme,
                          VALUE *const passed_values, const int passed_keyword_len, const VALUE *const passed_keywords,
@@ -352,30 +383,8 @@ args_setup_kw_parameters(rb_execution_context_t *const ec, const rb_iseq_t *cons
             found++;
         }
         else {
-            if (UNDEF_P(default_values[di])) {
-                locals[i] = Qnil;
-
-                if (LIKELY(i < VM_KW_SPECIFIED_BITS_MAX)) {
-                    unspecified_bits |= 0x01 << di;
-                }
-                else {
-                    if (NIL_P(unspecified_bits_value)) {
-                        /* fixnum -> hash */
-                        int j;
-                        unspecified_bits_value = rb_hash_new();
-
-                        for (j=0; j<VM_KW_SPECIFIED_BITS_MAX; j++) {
-                            if (unspecified_bits & (0x01 << j)) {
-                                rb_hash_aset(unspecified_bits_value, INT2FIX(j), Qtrue);
-                            }
-                        }
-                    }
-                    rb_hash_aset(unspecified_bits_value, INT2FIX(di), Qtrue);
-                }
-            }
-            else {
-                locals[i] = default_values[di];
-            }
+            args_setup_kw_parameters_not_found(default_values, locals, i, di,
+                                               &unspecified_bits, &unspecified_bits_value);
         }
     }
 
@@ -447,30 +456,8 @@ args_setup_kw_parameters_from_kwsplat(rb_execution_context_t *const ec, const rb
             locals[i] = value;
         }
         else {
-            if (UNDEF_P(default_values[di])) {
-                locals[i] = Qnil;
-
-                if (LIKELY(i < VM_KW_SPECIFIED_BITS_MAX)) {
-                    unspecified_bits |= 0x01 << di;
-                }
-                else {
-                    if (NIL_P(unspecified_bits_value)) {
-                        /* fixnum -> hash */
-                        int j;
-                        unspecified_bits_value = rb_hash_new();
-
-                        for (j=0; j<VM_KW_SPECIFIED_BITS_MAX; j++) {
-                            if (unspecified_bits & (0x01 << j)) {
-                                rb_hash_aset(unspecified_bits_value, INT2FIX(j), Qtrue);
-                            }
-                        }
-                    }
-                    rb_hash_aset(unspecified_bits_value, INT2FIX(di), Qtrue);
-                }
-            }
-            else {
-                locals[i] = default_values[di];
-            }
+            args_setup_kw_parameters_not_found(default_values, locals, i, di,
+                                               &unspecified_bits, &unspecified_bits_value);
         }
     }