Tweak docs for RngExt::random_range and SampleRange

src/distr/uniform.rs

@@ -419,8 +419,23 @@ where
 
 /// Range that supports generating a single sample efficiently.
 ///
-/// Any type implementing this trait can be used to specify the sampled range
-/// for `Rng::random_range`.
+/// See [`RngExt::random_range`] for examples; the method provides a convenient
+/// interface over this type.
+///
+/// # Examples
+///
+/// ```
+/// use rand::distr::uniform::SampleRange;
+/// let mut rng = rand::rng();
+///
+/// // Range and InclusiveRange are supported for many types:
+/// assert_eq!((9..10).sample_single(&mut rng), Ok(9));
+/// assert_eq!(('a'..='a').sample_single(&mut rng), Ok('a'));
+///
+/// // RangeTo and RangeToInclusive are supported for unsigned integers:
+/// assert_eq!((..1u8).sample_single(&mut rng), Ok(0));
+/// assert!((..=10u32).sample_single(&mut rng).unwrap() <= 10);
+/// ```
 pub trait SampleRange<T> {
     /// Generate a sample from the given range.
     fn sample_single<R: Rng + ?Sized>(self, rng: &mut R) -> Result<T, Error>;

src/rng.rs

@@ -129,8 +129,10 @@ pub trait RngExt: Rng {
     /// made from the given range. See also the [`Uniform`] distribution
     /// type which may be faster if sampling from the same range repeatedly.
     ///
-    /// All types support `low..high_exclusive` and `low..=high` range syntax.
-    /// Unsigned integer types also support `..high_exclusive` and `..=high` syntax.
+    /// All supported types may be sampled with `low..high_exclusive`
+    /// ([`Range`]) and `low..=high` ([`RangeInclusive`]) syntax. Unsigned
+    /// integer types also support `..high_exclusive` ([`RangeTo`]) and
+    /// `..=high` ([`RangeToInclusive`]) syntax.
     ///
     /// # Panics
     ///
@@ -144,17 +146,19 @@ pub trait RngExt: Rng {
     /// let mut rng = rand::rng();
     ///
     /// // Exclusive range
-    /// let n: u32 = rng.random_range(..10);
-    /// println!("{}", n);
-    /// let m: f64 = rng.random_range(-40.0..1.3e5);
-    /// println!("{}", m);
+    /// println!("{}", rng.random_range::<u32, _>(..10));
+    /// println!("{}", rng.random_range(-40.0..1.3e5));
     ///
     /// // Inclusive range
-    /// let n: u32 = rng.random_range(..=10);
-    /// println!("{}", n);
+    /// println!("{}", rng.random_range(-10..=10));
+    /// println!("{}", rng.random_range('a'..='z'));
     /// ```
     ///
     /// [`Uniform`]: distr::uniform::Uniform
+    /// [`Range`]: std::ops::Range
+    /// [`RangeInclusive`]: std::ops::RangeInclusive
+    /// [`RangeTo`]: std::ops::RangeTo
+    /// [`RangeToInclusive`]: std::ops::RangeToInclusive
     #[track_caller]
     fn random_range<T, R>(&mut self, range: R) -> T
     where