FIX: invalid output when converting date to integer without a time value

resolves: Oldes/Rebol-issues#2550

Author: Oldes

src/core/t-date.c

@@ -321,7 +321,9 @@ static const REBI64 DAYS_OF_JAN_1ST_1970 = 719468; // number of days for 1st Jan
 {
 	REBDAT d = VAL_DATE(date);
 	REBI64 epoch = (Days_Of_Date(d.date.day, d.date.month, d.date.year) - DAYS_OF_JAN_1ST_1970) * SECS_IN_DAY;
-	return epoch + ((VAL_TIME(date) + 500000000) / SEC_SEC);
+	REBI64 time = VAL_TIME(date);
+	if (time == NO_TIME) time = 0;
+	return epoch + ((time + 500000000) / SEC_SEC);
 }
 
 /***********************************************************************

src/tests/units/make-test.r3

@@ -92,6 +92,12 @@ Rebol [
 		--assert 1632142002 =   to integer! 20-Sep-2021/12:46:41.7
 		--assert 1632135512 = make integer! 20-Sep-2021/12:58:32+2:00
 		--assert 1632135512 =   to integer! 20-Sep-2021/12:58:32+2:00
+		;@@ https://github.com/Oldes/Rebol-issues/issues/2550
+		--assert 1685750400 == to integer! 3-Jun-2023
+		--assert 1685750400 == to integer! 3-Jun-2023/0:00
+		--assert 1685750400 == make integer! 3-Jun-2023
+		--assert 1685750400 == make integer! 3-Jun-2023/0:00
+
 	--test-- "make/to integer! string!"
 		;@@ https://github.com/Oldes/Rebol-issues/issues/2164
 		--assert 9223372036854775807 = to integer! "9223372036854775807"