From d5bb6056f16bae301b498bd44ad286685bb5e618 Mon Sep 17 00:00:00 2001
From: bmoxb <maxoblack@yahoo.com>
Date: Thu, 9 Mar 2023 18:55:28 +0000
Subject: [PATCH 1/4] Document the resulting values produced when using
`From<bool>` on floats
---
library/core/src/convert/num.rs | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/library/core/src/convert/num.rs b/library/core/src/convert/num.rs
index 4da7c323492..8c407d07c51 100644
--- a/library/core/src/convert/num.rs
+++ b/library/core/src/convert/num.rs
@@ -172,7 +172,8 @@ impl_from! { f32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0"
#[stable(feature = "float_from_bool", since = "1.68.0")]
#[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
impl const From<bool> for f32 {
- /// Converts `bool` to `f32` losslessly.
+ /// Converts `bool` to `f32` losslessly. The resulting value is `0.0` for
+ /// `false` and `1.0` for `true` values.
#[inline]
fn from(small: bool) -> Self {
small as u8 as Self
From 73016bb8d4a5f20dd07524854d29ff9177ccbe54 Mon Sep 17 00:00:00 2001
From: bmoxb <maxoblack@yahoo.com>
Date: Thu, 9 Mar 2023 20:36:26 +0000
Subject: [PATCH 2/4] Indicate that `0.0` refers to positive `0.0`
---
library/core/src/convert/num.rs | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/library/core/src/convert/num.rs b/library/core/src/convert/num.rs
index 8c407d07c51..205fe3d382e 100644
--- a/library/core/src/convert/num.rs
+++ b/library/core/src/convert/num.rs
@@ -172,8 +172,8 @@ impl_from! { f32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0"
#[stable(feature = "float_from_bool", since = "1.68.0")]
#[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
impl const From<bool> for f32 {
- /// Converts `bool` to `f32` losslessly. The resulting value is `0.0` for
- /// `false` and `1.0` for `true` values.
+ /// Converts `bool` to `f32` losslessly. The resulting value is positive
+ /// `0.0` for `false` and `1.0` for `true` values.
#[inline]
fn from(small: bool) -> Self {
small as u8 as Self
From 8d2bdb89c624d58feb0f077de6648787f8e6afbc Mon Sep 17 00:00:00 2001
From: bmoxb <maxoblack@yahoo.com>
Date: Thu, 9 Mar 2023 20:37:04 +0000
Subject: [PATCH 3/4] Add missing comment for f64
---
library/core/src/convert/num.rs | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/library/core/src/convert/num.rs b/library/core/src/convert/num.rs
index 205fe3d382e..baee008b7ed 100644
--- a/library/core/src/convert/num.rs
+++ b/library/core/src/convert/num.rs
@@ -182,7 +182,8 @@ impl const From<bool> for f32 {
#[stable(feature = "float_from_bool", since = "1.68.0")]
#[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
impl const From<bool> for f64 {
- /// Converts `bool` to `f64` losslessly.
+ /// Converts `bool` to `f64` losslessly. The resulting value is positive
+ /// `0.0` for `false` and `1.0` for `true` values.
#[inline]
fn from(small: bool) -> Self {
small as u8 as Self
From b439189236a8956eaf9cd37bd601f3df074716f2 Mon Sep 17 00:00:00 2001
From: bmoxb <maxoblack@yahoo.com>
Date: Thu, 9 Mar 2023 20:44:11 +0000
Subject: [PATCH 4/4] Add examples section which demonstrates the behaviour
(specifically the sign positive aspect)
---
library/core/src/convert/num.rs | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/library/core/src/convert/num.rs b/library/core/src/convert/num.rs
index baee008b7ed..a74a56bc5b2 100644
--- a/library/core/src/convert/num.rs
+++ b/library/core/src/convert/num.rs
@@ -174,6 +174,16 @@ impl_from! { f32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0"
impl const From<bool> for f32 {
/// Converts `bool` to `f32` losslessly. The resulting value is positive
/// `0.0` for `false` and `1.0` for `true` values.
+ ///
+ /// # Examples
+ /// ```
+ /// let x: f32 = false.into();
+ /// assert_eq!(x, 0.0);
+ /// assert!(x.is_sign_positive());
+ ///
+ /// let y: f32 = true.into();
+ /// assert_eq!(y, 1.0);
+ /// ```
#[inline]
fn from(small: bool) -> Self {
small as u8 as Self
@@ -184,6 +194,16 @@ impl const From<bool> for f32 {
impl const From<bool> for f64 {
/// Converts `bool` to `f64` losslessly. The resulting value is positive
/// `0.0` for `false` and `1.0` for `true` values.
+ ///
+ /// # Examples
+ /// ```
+ /// let x: f64 = false.into();
+ /// assert_eq!(x, 0.0);
+ /// assert!(x.is_sign_positive());
+ ///
+ /// let y: f64 = true.into();
+ /// assert_eq!(y, 1.0);
+ /// ```
#[inline]
fn from(small: bool) -> Self {
small as u8 as Self