Clean up E0207 explanation

[rust.git] / src / libcore / convert / num.rs

diff --git a/src/libcore/convert/num.rs b/src/libcore/convert/num.rs
index d976c8b7f43612b15431225619c7dcc5a40395aa..752199c94b8aed8802df0ab7997afe4e48da1183 100644 (file)
--- a/src/libcore/convert/num.rs
+++ b/src/libcore/convert/num.rs
@@ -13,7 +13,6 @@ pub trait Sealed {}
 /// Typically doesn’t need to be used directly.
 #[unstable(feature = "convert_float_to_int", issue = "67057")]
 pub trait FloatToInt<Int>: private::Sealed + Sized {
-    #[cfg(not(bootstrap))]
     #[unstable(feature = "float_approx_unchecked_to", issue = "67058")]
     #[doc(hidden)]
     unsafe fn approx_unchecked(self) -> Int;
@@ -26,7 +25,6 @@ impl private::Sealed for $Float {}
         $(
             #[unstable(feature = "convert_float_to_int", issue = "67057")]
             impl FloatToInt<$Int> for $Float {
-                #[cfg(not(bootstrap))]
                 #[doc(hidden)]
                 #[inline]
                 unsafe fn approx_unchecked(self) -> $Int {
@@ -49,8 +47,8 @@ macro_rules! impl_from {
         #[doc = $doc]
         impl From<$Small> for $Large {
             #[inline]
-            fn from(small: $Small) -> $Large {
-                small as $Large
+            fn from(small: $Small) -> Self {
+                small as Self
             }
         }
     };
@@ -179,7 +177,7 @@ impl TryFrom<$source> for $target {
             /// is outside of the range of the target type.
             #[inline]
             fn try_from(value: $source) -> Result<Self, Self::Error> {
-                Ok(value as $target)
+                Ok(value as Self)
             }
         }
     )*}
@@ -196,9 +194,9 @@ impl TryFrom<$source> for $target {
             /// number type. This returns an error if the source value
             /// is outside of the range of the target type.
             #[inline]
-            fn try_from(u: $source) -> Result<$target, TryFromIntError> {
+            fn try_from(u: $source) -> Result<Self, Self::Error> {
                 if u >= 0 {
-                    Ok(u as $target)
+                    Ok(u as Self)
                 } else {
                     Err(TryFromIntError(()))
                 }
@@ -218,11 +216,11 @@ impl TryFrom<$source> for $target {
             /// number type. This returns an error if the source value
             /// is outside of the range of the target type.
             #[inline]
-            fn try_from(u: $source) -> Result<$target, TryFromIntError> {
-                if u > (<$target>::max_value() as $source) {
+            fn try_from(u: $source) -> Result<Self, Self::Error> {
+                if u > (Self::max_value() as $source) {
                     Err(TryFromIntError(()))
                 } else {
-                    Ok(u as $target)
+                    Ok(u as Self)
                 }
             }
         }
@@ -240,13 +238,13 @@ impl TryFrom<$source> for $target {
             /// number type. This returns an error if the source value
             /// is outside of the range of the target type.
             #[inline]
-            fn try_from(u: $source) -> Result<$target, TryFromIntError> {
-                let min = <$target>::min_value() as $source;
-                let max = <$target>::max_value() as $source;
+            fn try_from(u: $source) -> Result<Self, Self::Error> {
+                let min = Self::min_value() as $source;
+                let max = Self::max_value() as $source;
                 if u < min || u > max {
                     Err(TryFromIntError(()))
                 } else {
-                    Ok(u as $target)
+                    Ok(u as Self)
                 }
             }
         }
@@ -366,3 +364,84 @@ mod ptr_try_from_impls {
     rev!(try_from_unbounded, isize, i32, i64);
     rev!(try_from_both_bounded, isize, i128);
 }
+
+// Conversion traits for non-zero integer types
+use crate::num::NonZeroI128;
+use crate::num::NonZeroI16;
+use crate::num::NonZeroI32;
+use crate::num::NonZeroI64;
+use crate::num::NonZeroI8;
+use crate::num::NonZeroIsize;
+use crate::num::NonZeroU128;
+use crate::num::NonZeroU16;
+use crate::num::NonZeroU32;
+use crate::num::NonZeroU64;
+use crate::num::NonZeroU8;
+use crate::num::NonZeroUsize;
+
+macro_rules! nzint_impl_from {
+    ($Small: ty, $Large: ty, #[$attr:meta], $doc: expr) => {
+        #[$attr]
+        #[doc = $doc]
+        impl From<$Small> for $Large {
+            #[inline]
+            fn from(small: $Small) -> Self {
+                // SAFETY: input type guarantees the value is non-zero
+                unsafe {
+                    Self::new_unchecked(small.get().into())
+                }
+            }
+        }
+    };
+    ($Small: ty, $Large: ty, #[$attr:meta]) => {
+        nzint_impl_from!($Small,
+                   $Large,
+                   #[$attr],
+                   concat!("Converts `",
+                           stringify!($Small),
+                           "` to `",
+                           stringify!($Large),
+                           "` losslessly."));
+    }
+}
+
+// Non-zero Unsigned -> Non-zero Unsigned
+nzint_impl_from! { NonZeroU8, NonZeroU16, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU8, NonZeroU32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU8, NonZeroU64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU8, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU8, NonZeroUsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU16, NonZeroU32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU16, NonZeroU64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU16, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU16, NonZeroUsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU32, NonZeroU64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU32, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU64, NonZeroU128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+
+// Non-zero Signed -> Non-zero Signed
+nzint_impl_from! { NonZeroI8, NonZeroI16, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI8, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI8, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI8, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI8, NonZeroIsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI16, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI16, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI16, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI16, NonZeroIsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI32, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI32, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroI64, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+
+// NonZero UnSigned -> Non-zero Signed
+nzint_impl_from! { NonZeroU8, NonZeroI16, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU8, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU8, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU8, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU8, NonZeroIsize, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU16, NonZeroI32, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU16, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU16, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU32, NonZeroI64, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU32, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }
+nzint_impl_from! { NonZeroU64, NonZeroI128, #[stable(feature = "nz_int_conv", since = "1.41.0")] }