Make eligible functions const.

src/format/mod.rs

@@ -350,7 +350,7 @@ pub struct ParseError(ParseErrorKind);
 
 impl ParseError {
     /// The category of parse error
-    pub fn kind(&self) -> ParseErrorKind {
+    pub const fn kind(&self) -> ParseErrorKind {
         self.0
     }
 }

src/month.rs

@@ -197,7 +197,7 @@ pub struct Months(pub(crate) u32);
 
 impl Months {
     /// Construct a new `Months` from a number of months
-    pub fn new(num: u32) -> Self {
+    pub const fn new(num: u32) -> Self {
         Self(num)
     }
 }

src/naive/date.rs

@@ -131,7 +131,7 @@ pub struct Days(pub(crate) u64);
 
 impl Days {
     /// Construct a new `Days` from a number of days
-    pub fn new(num: u64) -> Self {
+    pub const fn new(num: u64) -> Self {
         Self(num)
     }
 }
@@ -708,7 +708,7 @@ impl NaiveDate {
     /// assert_eq!(dt.time(), t);
     /// ```
     #[inline]
-    pub fn and_time(&self, time: NaiveTime) -> NaiveDateTime {
+    pub const fn and_time(&self, time: NaiveTime) -> NaiveDateTime {
         NaiveDateTime::new(*self, time)
     }
 
@@ -898,7 +898,7 @@ impl NaiveDate {
 
     /// Returns the packed ordinal-flags.
     #[inline]
-    fn of(&self) -> Of {
+    const fn of(&self) -> Of {
         Of((self.ymdf & 0b1_1111_1111_1111) as u32)
     }
 
@@ -1221,7 +1221,7 @@ impl NaiveDate {
     /// }
     /// ```
     #[inline]
-    pub fn iter_days(&self) -> NaiveDateDaysIterator {
+    pub const fn iter_days(&self) -> NaiveDateDaysIterator {
         NaiveDateDaysIterator { value: *self }
     }
 
@@ -1252,14 +1252,14 @@ impl NaiveDate {
     /// }
     /// ```
     #[inline]
-    pub fn iter_weeks(&self) -> NaiveDateWeeksIterator {
+    pub const fn iter_weeks(&self) -> NaiveDateWeeksIterator {
         NaiveDateWeeksIterator { value: *self }
     }
 
     /// Returns the [`NaiveWeek`] that the date belongs to, starting with the [`Weekday`]
     /// specified.
     #[inline]
-    pub fn week(&self, start: Weekday) -> NaiveWeek {
+    pub const fn week(&self, start: Weekday) -> NaiveWeek {
         NaiveWeek { date: *self, start }
     }
 

src/naive/datetime/mod.rs

@@ -131,7 +131,7 @@ impl NaiveDateTime {
     /// assert_eq!(dt.time(), t);
     /// ```
     #[inline]
-    pub fn new(date: NaiveDate, time: NaiveTime) -> NaiveDateTime {
+    pub const fn new(date: NaiveDate, time: NaiveTime) -> NaiveDateTime {
         NaiveDateTime { date, time }
     }
 
@@ -335,7 +335,7 @@ impl NaiveDateTime {
     /// assert_eq!(dt.date(), NaiveDate::from_ymd_opt(2016, 7, 8).unwrap());
     /// ```
     #[inline]
-    pub fn date(&self) -> NaiveDate {
+    pub const fn date(&self) -> NaiveDate {
         self.date
     }
 
@@ -350,7 +350,7 @@ impl NaiveDateTime {
     /// assert_eq!(dt.time(), NaiveTime::from_hms_opt(9, 10, 11).unwrap());
     /// ```
     #[inline]
-    pub fn time(&self) -> NaiveTime {
+    pub const fn time(&self) -> NaiveTime {
         self.time
     }
 

src/naive/internals.rs

@@ -141,7 +141,7 @@ impl YearFlags {
     }
 
     #[inline]
-    pub(super) fn nisoweeks(&self) -> u32 {
+    pub(super) const fn nisoweeks(&self) -> u32 {
         let YearFlags(flags) = *self;
         52 + ((0b0000_0100_0000_0110 >> flags as usize) & 1)
     }
@@ -294,7 +294,7 @@ impl Of {
     }
 
     #[inline]
-    pub(super) fn ordinal(&self) -> u32 {
+    pub(super) const fn ordinal(&self) -> u32 {
         let Of(of) = *self;
         of >> 4
     }
@@ -310,7 +310,7 @@ impl Of {
     }
 
     #[inline]
-    pub(super) fn flags(&self) -> YearFlags {
+    pub(super) const fn flags(&self) -> YearFlags {
         let Of(of) = *self;
         YearFlags((of & 0b1111) as u8)
     }
@@ -336,13 +336,13 @@ impl Of {
     }
 
     #[inline]
-    pub(super) fn succ(&self) -> Of {
+    pub(super) const fn succ(&self) -> Of {
         let Of(of) = *self;
         Of(of + (1 << 4))
     }
 
     #[inline]
-    pub(super) fn pred(&self) -> Of {
+    pub(super) const fn pred(&self) -> Of {
         let Of(of) = *self;
         Of(of - (1 << 4))
     }
@@ -398,7 +398,7 @@ impl Mdf {
     }
 
     #[inline]
-    pub(super) fn month(&self) -> u32 {
+    pub(super) const fn month(&self) -> u32 {
         let Mdf(mdf) = *self;
         mdf >> 9
     }
@@ -414,7 +414,7 @@ impl Mdf {
     }
 
     #[inline]
-    pub(super) fn day(&self) -> u32 {
+    pub(super) const fn day(&self) -> u32 {
         let Mdf(mdf) = *self;
         (mdf >> 4) & 0b1_1111
     }

src/naive/isoweek.rs

@@ -71,7 +71,7 @@ impl IsoWeek {
     /// assert_eq!(d, NaiveDate::from_ymd_opt(2014, 12, 29).unwrap());
     /// ```
     #[inline]
-    pub fn year(&self) -> i32 {
+    pub const fn year(&self) -> i32 {
         self.ywf >> 10
     }
 
@@ -88,7 +88,7 @@ impl IsoWeek {
     /// assert_eq!(d.iso_week().week(), 15);
     /// ```
     #[inline]
-    pub fn week(&self) -> u32 {
+    pub const fn week(&self) -> u32 {
         ((self.ywf >> 4) & 0x3f) as u32
     }
 
@@ -105,7 +105,7 @@ impl IsoWeek {
     /// assert_eq!(d.iso_week().week0(), 14);
     /// ```
     #[inline]
-    pub fn week0(&self) -> u32 {
+    pub const fn week0(&self) -> u32 {
         ((self.ywf >> 4) & 0x3f) as u32 - 1
     }
 }

src/offset/fixed.rs

@@ -93,13 +93,13 @@ impl FixedOffset {
 
     /// Returns the number of seconds to add to convert from UTC to the local time.
     #[inline]
-    pub fn local_minus_utc(&self) -> i32 {
+    pub const fn local_minus_utc(&self) -> i32 {
         self.local_minus_utc
     }
 
     /// Returns the number of seconds to add to convert from the local time to UTC.
     #[inline]
-    pub fn utc_minus_local(&self) -> i32 {
+    pub const fn utc_minus_local(&self) -> i32 {
         -self.local_minus_utc
     }
 }

src/offset/local/tz_info/parser.rs

@@ -224,7 +224,7 @@ pub(crate) struct Cursor<'a> {
 
 impl<'a> Cursor<'a> {
     /// Construct a new `Cursor` from remaining data
-    pub(crate) fn new(remaining: &'a [u8]) -> Self {
+    pub(crate) const fn new(remaining: &'a [u8]) -> Self {
         Self { remaining, read_count: 0 }
     }
 
@@ -233,7 +233,7 @@ impl<'a> Cursor<'a> {
     }
 
     /// Returns remaining data
-    pub(crate) fn remaining(&self) -> &'a [u8] {
+    pub(crate) const fn remaining(&self) -> &'a [u8] {
         self.remaining
     }
 

src/offset/local/tz_info/timezone.rs

@@ -438,12 +438,12 @@ pub(super) struct Transition {
 
 impl Transition {
     /// Construct a TZif file transition
-    pub(super) fn new(unix_leap_time: i64, local_time_type_index: usize) -> Self {
+    pub(super) const fn new(unix_leap_time: i64, local_time_type_index: usize) -> Self {
         Self { unix_leap_time, local_time_type_index }
     }
 
     /// Returns Unix leap time
-    fn unix_leap_time(&self) -> i64 {
+    const fn unix_leap_time(&self) -> i64 {
         self.unix_leap_time
     }
 }
@@ -459,12 +459,12 @@ pub(super) struct LeapSecond {
 
 impl LeapSecond {
     /// Construct a TZif file leap second
-    pub(super) fn new(unix_leap_time: i64, correction: i32) -> Self {
+    pub(super) const fn new(unix_leap_time: i64, correction: i32) -> Self {
         Self { unix_leap_time, correction }
     }
 
     /// Returns Unix leap time
-    fn unix_leap_time(&self) -> i64 {
+    const fn unix_leap_time(&self) -> i64 {
         self.unix_leap_time
     }
 }
@@ -572,12 +572,12 @@ impl LocalTimeType {
     }
 
     /// Returns offset from UTC in seconds
-    pub(crate) fn offset(&self) -> i32 {
+    pub(crate) const fn offset(&self) -> i32 {
         self.ut_offset
     }
 
     /// Returns daylight saving time indicator
-    pub(super) fn is_dst(&self) -> bool {
+    pub(super) const fn is_dst(&self) -> bool {
         self.is_dst
     }