diff --git a/complex.c b/complex.c
index c4d4f80848..de06151683 100644
--- a/complex.c
+++ b/complex.c
@@ -72,21 +72,21 @@ inline static VALUE
 f_add(VALUE x, VALUE y)
 {
     if (FIXNUM_ZERO_P(y))
-	return x;
+        return x;
     if (FIXNUM_ZERO_P(x))
-	return y;
+        return y;
 
     if (RB_INTEGER_TYPE_P(x) &&
         UNLIKELY(rb_method_basic_definition_p(rb_cInteger, idPLUS))) {
-      return rb_int_plus(x, y);
+        return rb_int_plus(x, y);
     }
     else if (RB_FLOAT_TYPE_P(x) &&
              UNLIKELY(rb_method_basic_definition_p(rb_cFloat, idPLUS))) {
-      return rb_float_plus(x, y);
+        return rb_float_plus(x, y);
     }
     else if (RB_TYPE_P(x, T_RATIONAL) &&
              UNLIKELY(rb_method_basic_definition_p(rb_cRational, idPLUS))) {
-      return rb_rational_plus(x, y);
+        return rb_rational_plus(x, y);
     }
 
     return rb_funcall(x, '+', 1, y);