version bump: 0.3.10 -> (technically breaking) -> 0.4.0
warning: technically breaking changes in `<new::Generator<'a, T, R> as std::fmt::Debug>`
   --> rand-0.3.16/src/lib.rs:647:10
    |
647 | #[derive(Debug)]
    |          ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::AsciiGenerator<'a, R> as std::fmt::Debug>`
   --> rand-0.3.16/src/lib.rs:667:10
    |
667 | #[derive(Debug)]
    |          ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::XorShiftRng as std::fmt::Debug>`
   --> rand-0.3.16/src/lib.rs:727:17
    |
727 | #[derive(Clone, Debug)]
    |                 ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::Open01<F> as std::fmt::Debug>`
   --> rand-0.3.16/src/lib.rs:817:10
    |
817 | #[derive(Debug)]
    |          ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::Closed01<F> as std::fmt::Debug>`
   --> rand-0.3.16/src/lib.rs:835:10
    |
835 | #[derive(Debug)]
    |          ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::StdRng as std::fmt::Debug>`
   --> rand-0.3.16/src/lib.rs:840:23
    |
840 | #[derive(Copy, Clone, Debug)]
    |                       ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::ThreadRngReseeder as std::fmt::Debug>`
   --> rand-0.3.16/src/lib.rs:903:10
    |
903 | #[derive(Debug)]
    |          ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::ThreadRng as std::fmt::Debug>`
   --> rand-0.3.16/src/lib.rs:918:17
    |
918 | #[derive(Clone, Debug)]
    |                 ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::RandSample<Sup> as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/mod.rs:56:10
   |
56 | #[derive(Debug)]
   |          ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::Weighted<T> as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/mod.rs:83:23
   |
83 | #[derive(Copy, Clone, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::WeightedChoice<'a, T> as std::fmt::Debug>`
   --> rand-0.3.16/src/distributions/mod.rs:116:10
    |
116 | #[derive(Debug)]
    |          ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::Range<X> as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/range.rs:49:23
   |
49 | #[derive(Clone, Copy, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::Gamma as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/gamma.rs:52:23
   |
52 | #[derive(Clone, Copy, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::gamma::GammaRepr as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/gamma.rs:57:23
   |
57 | #[derive(Clone, Copy, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::gamma::GammaSmallShape as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/gamma.rs:78:23
   |
78 | #[derive(Clone, Copy, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::gamma::GammaLargeShape as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/gamma.rs:88:23
   |
88 | #[derive(Clone, Copy, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::ChiSquared as std::fmt::Debug>`
   --> rand-0.3.16/src/distributions/gamma.rs:200:23
    |
200 | #[derive(Clone, Copy, Debug)]
    |                       ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::gamma::ChiSquaredRepr as std::fmt::Debug>`
   --> rand-0.3.16/src/distributions/gamma.rs:205:23
    |
205 | #[derive(Clone, Copy, Debug)]
    |                       ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::FisherF as std::fmt::Debug>`
   --> rand-0.3.16/src/distributions/gamma.rs:258:23
    |
258 | #[derive(Clone, Copy, Debug)]
    |                       ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::StudentT as std::fmt::Debug>`
   --> rand-0.3.16/src/distributions/gamma.rs:302:23
    |
302 | #[derive(Clone, Copy, Debug)]
    |                       ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::normal::StandardNormal as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/normal.rs:36:23
   |
36 | #[derive(Clone, Copy, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::Normal as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/normal.rs:91:23
   |
91 | #[derive(Clone, Copy, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::LogNormal as std::fmt::Debug>`
   --> rand-0.3.16/src/distributions/normal.rs:139:23
    |
139 | #[derive(Clone, Copy, Debug)]
    |                       ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::exponential::Exp1 as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/exponential.rs:37:23
   |
37 | #[derive(Clone, Copy, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::distributions::Exp as std::fmt::Debug>`
  --> rand-0.3.16/src/distributions/exponential.rs:74:23
   |
74 | #[derive(Clone, Copy, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::IsaacRng as std::fmt::Debug>`
   --> rand-0.3.16/src/isaac.rs:264:1
    |
264 | / impl fmt::Debug for IsaacRng {
265 | |     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
266 | |         write!(f, "IsaacRng {{}}")
267 | |     }
268 | | }
    | |_^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::Isaac64Rng as std::fmt::Debug>`
   --> rand-0.3.16/src/isaac.rs:513:1
    |
513 | / impl fmt::Debug for Isaac64Rng {
514 | |     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
515 | |         write!(f, "Isaac64Rng {{}}")
516 | |     }
517 | | }
    | |_^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::ChaChaRng as std::fmt::Debug>`
  --> rand-0.3.16/src/chacha.rs:29:23
   |
29 | #[derive(Copy, Clone, Debug)]
   |                       ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::reseeding::ReseedingRng<R, Rsdr> as std::fmt::Debug>`
  --> rand-0.3.16/src/reseeding.rs:24:10
   |
24 | #[derive(Debug)]
   |          ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::reseeding::ReseedWithDefault as std::fmt::Debug>`
   --> rand-0.3.16/src/reseeding.rs:136:23
    |
136 | #[derive(Clone, Copy, Debug)]
    |                       ^^^^^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `new::rand_impls::<impl new::Rand for [T; 31]>`
   --> rand_impls.rs:223:9
    |
223 | /         impl<T> Rand for [T; $n] where T: Rand {
224 | |             #[inline]
225 | |             fn rand<R: Rng>(_rng: &mut R) -> [T; $n] {
226 | |                 [_rng.gen::<$t>(), $(_rng.gen::<$ts>()),*]
227 | |             }
228 | |         }
    | |_________^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `new::rand_impls::<impl new::Rand for [T; 0]>`
   --> rand_impls.rs:231:9
    |
231 | /         impl<T> Rand for [T; $n] {
232 | |             fn rand<R: Rng>(_rng: &mut R) -> [T; $n] { [] }
233 | |         }
    | |_________^
    |
    = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::OsRng as std::fmt::Debug>`
  --> rand-0.3.16/src/os.rs:50:1
   |
50 | / impl fmt::Debug for OsRng {
51 | |     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
52 | |         write!(f, "OsRng {{}}")
53 | |     }
54 | | }
   | |_^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<new::read::ReadRng<R> as std::fmt::Debug>`
  --> rand-0.3.16/src/read.rs:33:10
   |
33 | #[derive(Debug)]
   |          ^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `Rng`
   --> rand-0.3.16/src/lib.rs:324:1
    |
324 | / pub trait Rng {
325 | |     /// Return the next random u32.
326 | |     ///
327 | |     /// This rarely needs to be called directly, prefer `r.gen()` to
...   |
594 | |     }
595 | | }
    | |_^
    |
note: added defaulted item to trait (technically breaking)
   --> rand-0.3.16/src/lib.rs:560:5
    |
560 | /     fn choose_mut<'a, T>(&mut self, values: &'a mut [T]) -> Option<&'a mut T> where Self: Sized {
561 | |         if values.is_empty() {
562 | |             None
563 | |         } else {
...   |
566 | |         }
567 | |     }
    | |_____^