Auto merge of #58015 - icefoxen:tryfrom-docs, r=SimonSapin

Expand docs for `TryFrom` and `TryInto`.

The examples are still lacking for now, both for module docs and for methods/impl's.  Will be adding those in further pushes.

Should hopefully resolve the doc concern in #33417 when finished?

1 files changed, 12 insertions, 0 deletions

diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 98b5fcd3ee4..fb40bccee6a 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -4442,6 +4442,9 @@ macro_rules! try_from_unbounded {
         impl TryFrom<$source> for $target {
             type Error = TryFromIntError;
 
+            /// Try to create the target number type from a source
+            /// number type. This returns an error if the source value
+            /// is outside of the range of the target type.
             #[inline]
             fn try_from(value: $source) -> Result<Self, Self::Error> {
                 Ok(value as $target)
@@ -4457,6 +4460,9 @@ macro_rules! try_from_lower_bounded {
         impl TryFrom<$source> for $target {
             type Error = TryFromIntError;
 
+            /// Try to create the target number type from a source
+            /// 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 >= 0 {
@@ -4476,6 +4482,9 @@ macro_rules! try_from_upper_bounded {
         impl TryFrom<$source> for $target {
             type Error = TryFromIntError;
 
+            /// Try to create the target number type from a source
+            /// 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 $source) {
@@ -4495,6 +4504,9 @@ macro_rules! try_from_both_bounded {
         impl TryFrom<$source> for $target {
             type Error = TryFromIntError;
 
+            /// Try to create the target number type from a source
+            /// 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;