merge revision(s) 254bed302752a401b5fcc3b6c65a9c93711d91d6,fad3023e94c45e7f03478732f7641b6f39ba9d12,3156fb0f2c3ebf8229f392c8502c08fe165ab181: [Backport #17218]

	Renamed `nurat_sub` compliant with `rb_rational_plus`

	---
	 internal/rational.h | 1 +
	 rational.c          | 6 +++---
	 2 files changed, 4 insertions(+), 3 deletions(-)

	Fix ArithmeticSequence#last and ArithmeticSequence#each for
	 non-integer sequences (#3870)

	[Bug #17218]
	[ruby-core:100312]
	---
	 common.mk                             |  2 +
	 enumerator.c                          | 99 ++++++++++++++++++++++++++++++++---
	 internal/numeric.h                    |  2 +
	 internal/rational.h                   |  2 +
	 numeric.c                             | 53 ++++++++++---------
	 rational.c                            | 28 +++++++---
	 test/ruby/test_arithmetic_sequence.rb | 10 ++++
	 7 files changed, 156 insertions(+), 40 deletions(-)

	test/ruby/test_arithmetic_sequence.rb: remove a duplicated test

	There is another "test_last_bug17218"
	---
	 test/ruby/test_arithmetic_sequence.rb | 5 -----
	 1 file changed, 5 deletions(-)

1 files changed, 29 insertions, 24 deletions

diff --git a/numeric.c b/numeric.c
index fa8961652b..3da0f7f6b0 100644
--- a/numeric.c
+++ b/numeric.c
@@ -1044,8 +1044,8 @@ rb_float_plus(VALUE x, VALUE y)
  * Returns a new Float which is the difference of +float+ and +other+.
  */
 
-static VALUE
-flo_minus(VALUE x, VALUE y)
+VALUE
+rb_float_minus(VALUE x, VALUE y)
 {
     if (RB_TYPE_P(y, T_FIXNUM)) {
 	return DBL2NUM(RFLOAT_VALUE(x) - (double)FIX2LONG(y));
@@ -1894,6 +1894,31 @@ flo_prev_float(VALUE vx)
     return DBL2NUM(y);
 }
 
+VALUE
+rb_float_floor(VALUE num, int ndigits)
+{
+    double number, f;
+    number = RFLOAT_VALUE(num);
+    if (number == 0.0) {
+	return ndigits > 0 ? DBL2NUM(number) : INT2FIX(0);
+    }
+    if (ndigits > 0) {
+	int binexp;
+	frexp(number, &binexp);
+	if (float_round_overflow(ndigits, binexp)) return num;
+	if (number > 0.0 && float_round_underflow(ndigits, binexp))
+	    return DBL2NUM(0.0);
+	f = pow(10, ndigits);
+	f = floor(number * f) / f;
+	return DBL2NUM(f);
+    }
+    else {
+	num = dbl2ival(floor(number));
+	if (ndigits < 0) num = rb_int_floor(num, ndigits);
+	return num;
+    }
+}
+
 /*
  *  call-seq:
  *     float.floor([ndigits])  ->  integer or float
@@ -1936,31 +1961,11 @@ flo_prev_float(VALUE vx)
 static VALUE
 flo_floor(int argc, VALUE *argv, VALUE num)
 {
-    double number, f;
     int ndigits = 0;
-
     if (rb_check_arity(argc, 0, 1)) {
 	ndigits = NUM2INT(argv[0]);
     }
-    number = RFLOAT_VALUE(num);
-    if (number == 0.0) {
-	return ndigits > 0 ? DBL2NUM(number) : INT2FIX(0);
-    }
-    if (ndigits > 0) {
-	int binexp;
-	frexp(number, &binexp);
-	if (float_round_overflow(ndigits, binexp)) return num;
-	if (number > 0.0 && float_round_underflow(ndigits, binexp))
-	    return DBL2NUM(0.0);
-	f = pow(10, ndigits);
-	f = floor(number * f) / f;
-	return DBL2NUM(f);
-    }
-    else {
-	num = dbl2ival(floor(number));
-	if (ndigits < 0) num = rb_int_floor(num, ndigits);
-	return num;
-    }
+    return rb_float_floor(num, ndigits);
 }
 
 /*
@@ -5790,7 +5795,7 @@ Init_Numeric(void)
     rb_define_method(rb_cFloat, "coerce", flo_coerce, 1);
     rb_define_method(rb_cFloat, "-@", rb_float_uminus, 0);
     rb_define_method(rb_cFloat, "+", rb_float_plus, 1);
-    rb_define_method(rb_cFloat, "-", flo_minus, 1);
+    rb_define_method(rb_cFloat, "-", rb_float_minus, 1);
     rb_define_method(rb_cFloat, "*", rb_float_mul, 1);
     rb_define_method(rb_cFloat, "/", rb_float_div, 1);
     rb_define_method(rb_cFloat, "quo", flo_quo, 1);