Tracking Issue for float conversion methods (float_conversions)

Feature gate: #![feature(float_conversions)]

This is a tracking issue for the float conversion methods from ACP rust-lang/libs-team#810: cast (float to float), to_int_saturating, to_int_checked, and to_int_strict on f16, f32, f64, and f128.

Public API

// core::convert
pub trait FloatToFloat<Flt> { /* sealed */ }

impl f32 { // and f16, f64, f128
    pub fn cast<Flt>(self) -> Flt where Self: FloatToFloat<Flt>;
    pub fn to_int_saturating<Int>(self) -> Int where Self: FloatToInt<Int>;
    pub fn to_int_checked<Int>(self) -> Option<Int> where Self: FloatToInt<Int>;
    pub fn to_int_strict<Int>(self) -> Int where Self: FloatToInt<Int>;
}

cast is self as Flt. to_int_saturating is self as Int (saturating, NaN to 0, per the libs-api decision). to_int_checked truncates toward zero and returns None on NaN, infinity, or out of range. to_int_strict is to_int_checked().unwrap().

Steps / History

(Remember to update the S-tracking-* label when checking boxes.)

• ACP: rust-lang/libs-team#810
• Implementation: #159954
• Final comment period (FCP)
• Stabilization PR

Unresolved Questions

• The ACP also proposes cast from integers to floats. It shares the cast method name on integer types with the integer-to-integer cast from rust-lang/libs-team#811, which is being unified with the rest of the integer cast methods in the meta-ACP rust-lang/libs-team#833, so it is left out here until that naming settles.
• to_int_wrapping (float to int) is an open question in the ACP and is not included.

Start with the public API and unresolved questions listed in this tracking issue, then read implementation PR #159954. The work is done when the final comment period and stabilization PR are complete and the tracking checklist and labels are updated.