Expand valid range

Author: Manishearth

components/calendar/src/calendar_arithmetic.rs

@@ -7,12 +7,16 @@ use crate::options::{DateFromFieldsOptions, MissingFieldsStrategy, Overflow};
 use crate::types::{DateFields, DayOfYear, MonthCode};
 use crate::{types, Calendar, DateDuration, DateDurationUnit, DateError, RangeError};
 use core::cmp::Ordering;
+use core::ops::RangeInclusive;
 use core::convert::TryInto;
 use core::fmt::Debug;
 use core::hash::{Hash, Hasher};
 use core::marker::PhantomData;
 use tinystr::tinystr;
 
+/// The range ±2²⁷. We use i32::MIN since it is -2³¹
+const VALID_YEAR_RANGE: RangeInclusive<i32> = (i32::MIN / 16)..=-(i32::MIN / 16);
+
 #[derive(Debug)]
 #[allow(clippy::exhaustive_structs)] // this type is stable
 pub(crate) struct ArithmeticDate<C: CalendarArithmetic> {
@@ -492,7 +496,7 @@ where
                     },
                 },
                 (Some(era), Some(era_year)) => {
-                    range_check(era_year, "year", -1_000_000..=1_000_000)?;
+                    range_check(era_year, "year", VALID_YEAR_RANGE)?;
                     let era_year_as_year_info = cal.year_info_from_era(era, era_year)?;
                     if let Some(extended_year) = fields.extended_year {
                         if era_year_as_year_info != extended_year_as_year_info(extended_year, cal)?

components/calendar/src/date.rs

@@ -125,7 +125,7 @@ impl<A: AsCalendar> Date<A> {
     ///
     /// The year is `extended_year` if no era is provided.
     ///
-    /// This function will not accept year/extended_year values that are outside of the range `[-1_000_000, 1_000_000]`,
+    /// This function will not accept year/extended_year values that are outside of the range `[-2²⁷, 2²⁷]`,
     /// regardless of the calendar, instead returning a [`DateError::Range`]. See [`Date::try_from_fields()`] for more
     /// information.
     #[inline]
@@ -148,7 +148,7 @@ impl<A: AsCalendar> Date<A> {
     /// and the month as either ordinal or month code. It can constrain out-of-bounds values
     /// and fill in missing fields. See [`DateFromFieldsOptions`] for more information.
     ///
-    /// This function will not accept year/extended_year values that are outside of the range `[-1_000_000, 1_000_000]`,
+    /// This function will not accept year/extended_year values that are outside of the range `[-2²⁷, 2²⁷]`,
     /// regardless of the calendar, instead returning a [`DateError::Range`]. This is to protect clients
     /// from bugs due to arithmetic overflow. Currently, calendar-specific `Date::try_new_calendarname()` constructors
     /// do not do this, though we may change that behavior in the future.