From 0ad9f47fc64cc59790d33282109faae43d78555f Mon Sep 17 00:00:00 2001
From: Jacob Pratt <jacob@jhpratt.dev>
Date: Tue, 22 Mar 2022 02:53:20 -0400
Subject: [PATCH] Add tests for size, alignment, trait impls

This ensures that nothing will regress without knowing. As it turns out,
there was a missing implementation that was caught during this. As such,
`impl AddAssign<Duration> for `StdDuration` was added in this commit as
well.
---
 src/duration.rs               |  11 +-
 tests/integration/duration.rs |  11 +
 tests/integration/main.rs     |   8 +-
 tests/integration/meta.rs     | 931 ++++++++++++++++++++++++++++++++++
 4 files changed, 959 insertions(+), 2 deletions(-)
 create mode 100644 tests/integration/meta.rs

diff --git a/src/duration.rs b/src/duration.rs
index 7cb26d362d..ee7af639b6 100644
--- a/src/duration.rs
+++ b/src/duration.rs
@@ -4,7 +4,7 @@ use core::cmp::Ordering;
 use core::convert::{TryFrom, TryInto};
 use core::fmt;
 use core::iter::Sum;
-use core::ops::{Add, Div, Mul, Neg, Sub, SubAssign};
+use core::ops::{Add, AddAssign, Div, Mul, Neg, Sub, SubAssign};
 use core::time::Duration as StdDuration;
 
 use crate::error;
@@ -837,6 +837,15 @@ impl Add<Duration> for StdDuration {
 
 impl_add_assign!(Duration: Self, StdDuration);
 
+impl AddAssign<Duration> for StdDuration {
+    fn add_assign(&mut self, rhs: Duration) {
+        *self = (*self + rhs).try_into().expect(
+            "Cannot represent a resulting duration in std. Try `let x = x + rhs;`, which will \
+             change the type.",
+        );
+    }
+}
+
 impl Neg for Duration {
     type Output = Self;
 
diff --git a/tests/integration/duration.rs b/tests/integration/duration.rs
index 9fb4a2a4a9..d20eb9a7f0 100644
--- a/tests/integration/duration.rs
+++ b/tests/integration/duration.rs
@@ -471,6 +471,17 @@ fn add_assign_std() {
     assert_eq!(duration, 0.seconds());
 }
 
+#[test]
+fn std_add_assign() {
+    let mut duration = 1.std_seconds();
+    duration += 1.seconds();
+    assert_eq!(duration, 2.seconds());
+
+    let mut duration = 500.std_milliseconds();
+    duration += 500.milliseconds();
+    assert_eq!(duration, 1.seconds());
+}
+
 #[test]
 fn neg() {
     assert_eq!(-(1.seconds()), (-1).seconds());
diff --git a/tests/integration/main.rs b/tests/integration/main.rs
index 3fe04d90ce..ce4bd724b8 100644
--- a/tests/integration/main.rs
+++ b/tests/integration/main.rs
@@ -28,7 +28,12 @@
     unused_qualifications,
     variant_size_differences
 )]
-#![allow(clippy::cognitive_complexity, clippy::clone_on_copy, clippy::cmp_owned)]
+#![allow(
+    clippy::clone_on_copy,
+    clippy::cmp_owned,
+    clippy::cognitive_complexity,
+    clippy::missing_const_for_fn
+)]
 
 extern crate quickcheck_dep as quickcheck;
 
@@ -55,6 +60,7 @@ mod format_description;
 mod formatting;
 mod instant;
 mod macros;
+mod meta;
 mod month;
 mod offset_date_time;
 mod parse_format_description;
diff --git a/tests/integration/meta.rs b/tests/integration/meta.rs
new file mode 100644
index 0000000000..515de7805d
--- /dev/null
+++ b/tests/integration/meta.rs
@@ -0,0 +1,931 @@
+use std::borrow::Borrow;
+use std::convert::TryFrom;
+use std::error::Error as StdError;
+use std::fmt::{Debug, Display};
+use std::hash::Hash;
+use std::iter::Sum;
+use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Neg, Sub, SubAssign};
+use std::panic::{RefUnwindSafe, UnwindSafe};
+use std::time::{Duration as StdDuration, Instant as StdInstant, SystemTime};
+
+use quickcheck_dep::Arbitrary;
+use rand::distributions::{Distribution, Standard};
+use serde::{Deserialize, Serialize};
+use time::format_description::{modifier, well_known, Component, FormatItem};
+use time::formatting::Formattable;
+use time::parsing::{Parsable, Parsed};
+use time::{
+    error, ext, Date, Duration, Error, Instant, Month, OffsetDateTime, PrimitiveDateTime, Time,
+    UtcOffset, Weekday,
+};
+
+#[test]
+fn alignment() {
+    macro_rules! assert_alignment {
+        ($t:ty, $alignment:literal) => {
+            assert_eq!(
+                ::core::mem::align_of::<$t>(),
+                $alignment,
+                concat!("alignment of `", stringify!($t), "` was ", $alignment)
+            );
+        };
+    }
+
+    assert_alignment!(Date, 4);
+    assert_alignment!(Duration, 8);
+    assert_alignment!(Error, 8);
+    assert_alignment!(Month, 1);
+    assert_alignment!(OffsetDateTime, 4);
+    assert_alignment!(PrimitiveDateTime, 4);
+    assert_alignment!(Time, 4);
+    assert_alignment!(UtcOffset, 1);
+    assert_alignment!(Weekday, 1);
+
+    assert_alignment!(Option<Date>, 4);
+    assert_alignment!(Option<Duration>, 8);
+    assert_alignment!(Option<Error>, 8);
+    assert_alignment!(Option<Month>, 1);
+    assert_alignment!(Option<OffsetDateTime>, 4);
+    assert_alignment!(Option<PrimitiveDateTime>, 4);
+    assert_alignment!(Option<Time>, 4);
+    assert_alignment!(Option<UtcOffset>, 1);
+    assert_alignment!(Option<Weekday>, 1);
+}
+
+#[test]
+fn size() {
+    macro_rules! assert_size {
+        ($t:ty, $size:literal) => {
+            assert_eq!(
+                ::core::mem::size_of::<$t>(),
+                $size,
+                concat!("size of `", stringify!($t), "` was ", $size)
+            );
+        };
+    }
+
+    assert_size!(Date, 4);
+    assert_size!(Duration, 16);
+    assert_size!(Error, 56);
+    assert_size!(Month, 1);
+    assert_size!(OffsetDateTime, 16);
+    assert_size!(PrimitiveDateTime, 12);
+    assert_size!(Time, 8);
+    assert_size!(UtcOffset, 3);
+    assert_size!(Weekday, 1);
+
+    assert_size!(Option<Date>, 8);
+    assert_size!(Option<Duration>, 16);
+    assert_size!(Option<Error>, 56);
+    assert_size!(Option<Month>, 1);
+    assert_size!(Option<OffsetDateTime>, 16);
+    assert_size!(Option<PrimitiveDateTime>, 12);
+    assert_size!(Option<Time>, 8);
+    assert_size!(Option<UtcOffset>, 4);
+    assert_size!(Option<Weekday>, 1);
+}
+
+macro_rules! assert_obj_safe {
+    ($($xs:path),+ $(,)?) => {
+        $(const _: Option<&dyn $xs> = None;)+
+    };
+}
+
+assert_obj_safe!(ext::NumericalDuration);
+assert_obj_safe!(ext::NumericalStdDuration);
+assert_obj_safe!(Parsable);
+// `Formattable` is not object safe.
+
+macro_rules! assert_impl {
+    ($($(@$lifetimes:lifetime),+ ;)? $type:ty: $($trait:path),+ $(,)?) => {
+        const _: fn() = || {
+            fn assert_impl_all<$($($lifetimes,)+)? T: ?Sized $(+ $trait)+>() {}
+            assert_impl_all::<$type>();
+        };
+    };
+}
+
+assert_impl! { @'a; Date:
+    Add<Duration, Output = Date>,
+    Add<StdDuration, Output = Date>,
+    AddAssign<Duration>,
+    AddAssign<StdDuration>,
+    Arbitrary,
+    Clone,
+    Debug,
+    Deserialize<'a>,
+    Display,
+    Hash,
+    Ord,
+    PartialEq<Date>,
+    PartialOrd<Date>,
+    Serialize,
+    Sub<Date, Output = Duration>,
+    Sub<Duration, Output = Date>,
+    Sub<StdDuration, Output = Date>,
+    SubAssign<Duration>,
+    SubAssign<StdDuration>,
+    TryFrom<Parsed, Error = error::TryFromParsed>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { @'a; Duration:
+    Add<Duration, Output = Duration>,
+    Add<StdDuration, Output = Duration>,
+    AddAssign<Duration>,
+    AddAssign<StdDuration>,
+    Arbitrary,
+    Clone,
+    Debug,
+    Default,
+    Deserialize<'a>,
+    Div<Duration, Output = f64>,
+    Div<StdDuration, Output = f64>,
+    Div<f32, Output = Duration>,
+    Div<f64, Output = Duration>,
+    Div<i16, Output = Duration>,
+    Div<i32, Output = Duration>,
+    Div<i8, Output = Duration>,
+    Div<u16, Output = Duration>,
+    Div<u32, Output = Duration>,
+    Div<u8, Output = Duration>,
+    DivAssign<f32>,
+    DivAssign<f64>,
+    DivAssign<i16>,
+    DivAssign<i32>,
+    DivAssign<i8>,
+    DivAssign<u16>,
+    DivAssign<u32>,
+    DivAssign<u8>,
+    Hash,
+    Mul<f32, Output = Duration>,
+    Mul<f64, Output = Duration>,
+    Mul<i16, Output = Duration>,
+    Mul<i32, Output = Duration>,
+    Mul<i8, Output = Duration>,
+    Mul<u16, Output = Duration>,
+    Mul<u32, Output = Duration>,
+    Mul<u8, Output = Duration>,
+    MulAssign<f32>,
+    MulAssign<f64>,
+    MulAssign<i16>,
+    MulAssign<i32>,
+    MulAssign<i8>,
+    MulAssign<u16>,
+    MulAssign<u32>,
+    MulAssign<u8>,
+    Neg<Output = Duration>,
+    Ord,
+    PartialEq<Duration>,
+    PartialEq<StdDuration>,
+    PartialOrd<Duration>,
+    PartialOrd<StdDuration>,
+    Serialize,
+    Sub<Duration, Output = Duration>,
+    Sub<StdDuration, Output = Duration>,
+    SubAssign<Duration>,
+    SubAssign<StdDuration>,
+    Sum<&'a Duration>,
+    Sum<Duration>,
+    TryFrom<StdDuration, Error = error::ConversionRange>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { Instant:
+    Add<Duration, Output = Instant>,
+    Add<StdDuration, Output = Instant>,
+    AddAssign<Duration>,
+    AddAssign<StdDuration>,
+    AsRef<StdInstant>,
+    Borrow<StdInstant>,
+    Clone,
+    Debug,
+    From<StdInstant>,
+    Hash,
+    Ord,
+    PartialEq<Instant>,
+    PartialEq<StdInstant>,
+    PartialOrd<Instant>,
+    PartialOrd<StdInstant>,
+    Sub<Duration, Output = Instant>,
+    Sub<StdDuration, Output = Instant>,
+    Sub<Instant, Output = Duration>,
+    Sub<StdInstant, Output = Duration>,
+    SubAssign<Duration>,
+    SubAssign<StdDuration>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { @'a; OffsetDateTime:
+    Add<Duration, Output = OffsetDateTime>,
+    Add<StdDuration, Output = OffsetDateTime>,
+    AddAssign<Duration>,
+    AddAssign<StdDuration>,
+    Arbitrary,
+    Clone,
+    Debug,
+    Deserialize<'a>,
+    Display,
+    From<SystemTime>,
+    Hash,
+    Ord,
+    PartialEq<OffsetDateTime>,
+    PartialEq<SystemTime>,
+    PartialOrd<OffsetDateTime>,
+    PartialOrd<SystemTime>,
+    Serialize,
+    Sub<OffsetDateTime, Output = Duration>,
+    Sub<SystemTime, Output = Duration>,
+    Sub<Duration, Output = OffsetDateTime>,
+    Sub<StdDuration, Output = OffsetDateTime>,
+    SubAssign<Duration>,
+    SubAssign<StdDuration>,
+    TryFrom<Parsed, Error = error::TryFromParsed>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { @'a; PrimitiveDateTime:
+    Add<Duration, Output = PrimitiveDateTime>,
+    Add<StdDuration, Output = PrimitiveDateTime>,
+    AddAssign<Duration>,
+    AddAssign<StdDuration>,
+    Arbitrary,
+    Clone,
+    Debug,
+    Deserialize<'a>,
+    Display,
+    Hash,
+    Ord,
+    PartialEq<PrimitiveDateTime>,
+    PartialOrd<PrimitiveDateTime>,
+    Serialize,
+    Sub<Duration, Output = PrimitiveDateTime>,
+    Sub<StdDuration, Output = PrimitiveDateTime>,
+    Sub<PrimitiveDateTime>,
+    SubAssign<Duration>,
+    SubAssign<StdDuration>,
+    TryFrom<Parsed, Error = error::TryFromParsed>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { @'a; Time:
+    Add<Duration, Output = Time>,
+    Add<StdDuration, Output = Time>,
+    AddAssign<Duration>,
+    AddAssign<StdDuration>,
+    Arbitrary,
+    Clone,
+    Debug,
+    Deserialize<'a>,
+    Display,
+    Hash,
+    Ord,
+    PartialEq<Time>,
+    PartialOrd<Time>,
+    Serialize,
+    Sub<Duration, Output = Time>,
+    Sub<StdDuration, Output = Time>,
+    Sub<Time, Output = Duration>,
+    SubAssign<Duration>,
+    SubAssign<StdDuration>,
+    TryFrom<Parsed, Error = error::TryFromParsed>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { @'a; UtcOffset:
+    Arbitrary,
+    Clone,
+    Debug,
+    Deserialize<'a>,
+    Display,
+    Hash,
+    Neg,
+    Ord,
+    PartialEq<UtcOffset>,
+    PartialOrd<UtcOffset>,
+    Serialize,
+    TryFrom<Parsed, Error = error::TryFromParsed>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { error::ComponentRange:
+    Clone,
+    Debug,
+    Display,
+    StdError,
+    serde::de::Expected,
+    Hash,
+    PartialEq<error::ComponentRange>,
+    TryFrom<Error, Error = error::DifferentVariant>,
+    TryFrom<error::TryFromParsed, Error = error::DifferentVariant>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { error::ConversionRange:
+    Clone,
+    Debug,
+    Display,
+    StdError,
+    PartialEq<error::ConversionRange>,
+    TryFrom<Error, Error = error::DifferentVariant>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { error::DifferentVariant:
+    Clone,
+    Debug,
+    Display,
+    StdError,
+    PartialEq<error::DifferentVariant>,
+    TryFrom<Error, Error = error::DifferentVariant>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { error::IndeterminateOffset:
+    Clone,
+    Debug,
+    Display,
+    StdError,
+    PartialEq<error::IndeterminateOffset>,
+    TryFrom<Error, Error = error::DifferentVariant>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Day:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Day>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Hour:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Hour>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Minute:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Minute>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Month:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Month>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::OffsetHour:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::OffsetHour>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::OffsetMinute:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::OffsetMinute>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::OffsetSecond:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::OffsetSecond>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Ordinal:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Ordinal>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Period:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Period>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Second:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Second>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Subsecond:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Subsecond>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::WeekNumber:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::WeekNumber>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Weekday:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Weekday>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Year:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Year>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { well_known::Rfc2822:
+    Clone,
+    Debug,
+    PartialEq<well_known::Rfc2822>,
+    Copy,
+    Eq,
+    Formattable,
+    Parsable,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { well_known::Rfc3339:
+    Clone,
+    Debug,
+    PartialEq<well_known::Rfc3339>,
+    Copy,
+    Eq,
+    Formattable,
+    Parsable,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { Parsed:
+    Clone,
+    Debug,
+    Copy,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { @'a; Month:
+    Arbitrary,
+    Clone,
+    Debug,
+    Deserialize<'a>,
+    Display,
+    Hash,
+    PartialEq<Month>,
+    TryFrom<u8, Error = error::ComponentRange>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { @'a; Weekday:
+    Arbitrary,
+    Clone,
+    Debug,
+    Deserialize<'a>,
+    Display,
+    Hash,
+    PartialEq<Weekday>,
+    Serialize,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { Error:
+    Debug,
+    Display,
+    StdError,
+    From<error::ComponentRange>,
+    From<error::ConversionRange>,
+    From<error::DifferentVariant>,
+    From<error::Format>,
+    From<error::IndeterminateOffset>,
+    From<error::InvalidFormatDescription>,
+    From<error::Parse>,
+    From<error::ParseFromDescription>,
+    From<error::TryFromParsed>,
+    Send,
+    Sync,
+    Unpin,
+}
+assert_impl! { error::Format:
+    Debug,
+    Display,
+    StdError,
+    From<std::io::Error>,
+    TryFrom<Error, Error = error::DifferentVariant>,
+    Send,
+    Sync,
+    Unpin,
+}
+assert_impl! { error::InvalidFormatDescription:
+    Clone,
+    Debug,
+    Display,
+    StdError,
+    PartialEq<error::InvalidFormatDescription>,
+    TryFrom<Error, Error = error::DifferentVariant>,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { error::Parse:
+    Clone,
+    Debug,
+    Display,
+    StdError,
+    From<error::ParseFromDescription>,
+    From<error::TryFromParsed>,
+    PartialEq<error::Parse>,
+    TryFrom<Error, Error = error::DifferentVariant>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { error::ParseFromDescription:
+    Clone,
+    Debug,
+    Display,
+    StdError,
+    PartialEq<error::ParseFromDescription>,
+    TryFrom<Error, Error = error::DifferentVariant>,
+    TryFrom<error::Parse, Error = error::DifferentVariant>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { error::TryFromParsed:
+    Clone,
+    Debug,
+    Display,
+    StdError,
+    From<error::ComponentRange>,
+    PartialEq<error::TryFromParsed>,
+    TryFrom<Error, Error = error::DifferentVariant>,
+    TryFrom<error::Parse, Error = error::DifferentVariant>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { @'a; Component:
+    Clone,
+    Debug,
+    PartialEq<Component>,
+    PartialEq<FormatItem<'a>>,
+    TryFrom<FormatItem<'a>, Error = error::DifferentVariant>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { @'a; FormatItem<'_>:
+    Clone,
+    Debug,
+    From<&'a [FormatItem<'a>]>,
+    From<Component>,
+    PartialEq<&'a [FormatItem<'a>]>,
+    PartialEq<Component>,
+    PartialEq<FormatItem<'a>>,
+    Eq,
+    Formattable,
+    Parsable,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { @'a; &[FormatItem<'_>]:
+    PartialEq<FormatItem<'a>>,
+    TryFrom<FormatItem<'a>, Error = error::DifferentVariant>,
+}
+assert_impl! { modifier::MonthRepr:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::MonthRepr>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::Padding:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::Padding>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::SubsecondDigits:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::SubsecondDigits>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::WeekNumberRepr:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::WeekNumberRepr>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::WeekdayRepr:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::WeekdayRepr>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { modifier::YearRepr:
+    Clone,
+    Debug,
+    Default,
+    PartialEq<modifier::YearRepr>,
+    Copy,
+    Eq,
+    RefUnwindSafe,
+    Send,
+    Sync,
+    Unpin,
+    UnwindSafe,
+}
+assert_impl! { Standard:
+    Distribution<Date>,
+    Distribution<Duration>,
+    Distribution<OffsetDateTime>,
+    Distribution<PrimitiveDateTime>,
+    Distribution<Time>,
+    Distribution<UtcOffset>,
+    Distribution<Month>,
+    Distribution<Weekday>,
+}
+assert_impl! { StdDuration:
+    Add<Duration, Output = Duration>,
+    AddAssign<Duration>,
+    Div<Duration, Output = f64>,
+    PartialEq<Duration>,
+    PartialOrd<Duration>,
+    Sub<Duration, Output = Duration>,
+    SubAssign<Duration>,
+    TryFrom<Duration>,
+}
+assert_impl! { StdInstant:
+    Add<Duration, Output = StdInstant>,
+    AddAssign<Duration>,
+    Sub<Duration, Output = StdInstant>,
+    SubAssign<Duration>,
+    PartialEq<Instant>,
+    PartialOrd<Instant>,
+    From<Instant>,
+    Sub<Instant>,
+}
+assert_impl! { SystemTime:
+    Add<Duration, Output = SystemTime>,
+    AddAssign<Duration>,
+    Sub<Duration, Output = SystemTime>,
+    SubAssign<Duration>,
+    From<OffsetDateTime>,
+    PartialEq<OffsetDateTime>,
+    PartialOrd<OffsetDateTime>,
+    Sub<OffsetDateTime>,
+}
+assert_impl! { i8:
+    Mul<Duration>,
+}
+assert_impl! { i16:
+    Mul<Duration>,
+}
+assert_impl! { i32:
+    Mul<Duration>,
+}
+assert_impl! { u8:
+    Mul<Duration>,
+    From<Month>,
+}
+assert_impl! { u16:
+    Mul<Duration>,
+}
+assert_impl! { u32:
+    Mul<Duration>,
+}
+assert_impl! { f32:
+    Mul<Duration>,
+}
+assert_impl! { f64:
+    Mul<Duration>,
+}