Make .inf and .sup const

[Chris00]

Wouldn't it be desirable for the methods .inf() and .sup() to be constant? That would allow, for example, const_interval!(0., Interval::PI.sup()).

[unageek]

Sure, but if I try making them const, I get the following errors at the moment.

error[E0658]: floating point arithmetic is not allowed in constant functions
  --> src/interval.rs:67:9
   |
67 |         -extract0(self.rep)
   |         ^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #57241 <https://github.com/rust-lang/rust/issues/57241> for more information

error: `core::f64::<impl f64>::is_nan` is not yet stable as a const fn
  --> src/numeric.rs:29:12
   |
29 |         if x.is_nan() {
   |            ^^^^^^^^^^

error[E0658]: floating point arithmetic is not allowed in constant functions
  --> src/numeric.rs:32:19
   |
32 |         } else if x == 0.0 {
   |                   ^^^^^^^^
   |
   = note: see issue #57241 <https://github.com/rust-lang/rust/issues/57241> for more information

error: `core::f64::<impl f64>::is_nan` is not yet stable as a const fn
   --> src/numeric.rs:206:12
    |
206 |         if x.is_nan() {
    |            ^^^^^^^^^^

error[E0658]: floating point arithmetic is not allowed in constant functions
   --> src/numeric.rs:209:19
    |
209 |         } else if x == 0.0 {
    |                   ^^^^^^^^
    |
    = note: see issue #57241 <https://github.com/rust-lang/rust/issues/57241> for more information

[Chris00]

Ah, indeed, I hadn't tried. We'll have to wait that they stabilize the feature further...