Auto merge of #59433 - Centril:rollup, r=Centril

Rollup of 10 pull requests

Successful merges:

 - #59150 (Expand suggestions for type ascription parse errors)
 - #59232 (Merge `Promoted` and `Static` in `mir::Place`)
 - #59267 (Provide suggestion when using field access instead of path)
 - #59315 (Add no_hash to query macro and move some queries over)
 - #59334 (Update build instructions in README.md)
 - #59362 (Demo `FromIterator` short-circuiting)
 - #59374 (Simplify checked_duration_since)
 - #59389 (replace redundant note in deprecation warning)
 - #59410 (Clarify `{Ord,f32,f64}::clamp` docs a little)
 - #59419 (Utilize `?` instead of `return None`.)

Failed merges:

r? @ghost

9 files changed, 60 insertions, 49 deletions

diff --git a/src/libstd/f32.rs b/src/libstd/f32.rs
index 688d9c1aabb..796908b0df9 100644
--- a/src/libstd/f32.rs
+++ b/src/libstd/f32.rs
@@ -960,17 +960,27 @@ impl f32 {
     pub fn atanh(self) -> f32 {
         0.5 * ((2.0 * self) / (1.0 - self)).ln_1p()
     }
-    /// Returns max if self is greater than max, and min if self is less than min.
-    /// Otherwise this returns self.  Panics if min > max, min equals NaN, or max equals NaN.
+
+    /// Restrict a value to a certain interval unless it is NaN.
+    ///
+    /// Returns `max` if `self` is greater than `max`, and `min` if `self` is
+    /// less than `min`. Otherwise this returns `self`.
+    ///
+    /// Not that this function returns NaN if the initial value was NaN as
+    /// well.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `min > max`, `min` is NaN, or `max` is NaN.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(clamp)]
-    /// assert!((-3.0f32).clamp(-2.0f32, 1.0f32) == -2.0f32);
-    /// assert!((0.0f32).clamp(-2.0f32, 1.0f32) == 0.0f32);
-    /// assert!((2.0f32).clamp(-2.0f32, 1.0f32) == 1.0f32);
-    /// assert!((std::f32::NAN).clamp(-2.0f32, 1.0f32).is_nan());
+    /// assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0);
+    /// assert!((0.0f32).clamp(-2.0, 1.0) == 0.0);
+    /// assert!((2.0f32).clamp(-2.0, 1.0) == 1.0);
+    /// assert!((std::f32::NAN).clamp(-2.0, 1.0).is_nan());
     /// ```
     #[unstable(feature = "clamp", issue = "44095")]
     #[inline]
diff --git a/src/libstd/f64.rs b/src/libstd/f64.rs
index b171e1c7ac9..e679a7d2e8c 100644
--- a/src/libstd/f64.rs
+++ b/src/libstd/f64.rs
@@ -882,17 +882,26 @@ impl f64 {
         0.5 * ((2.0 * self) / (1.0 - self)).ln_1p()
     }
 
-    /// Returns max if self is greater than max, and min if self is less than min.
-    /// Otherwise this returns self.  Panics if min > max, min equals NaN, or max equals NaN.
+    /// Restrict a value to a certain interval unless it is NaN.
+    ///
+    /// Returns `max` if `self` is greater than `max`, and `min` if `self` is
+    /// less than `min`. Otherwise this returns `self`.
+    ///
+    /// Not that this function returns NaN if the initial value was NaN as
+    /// well.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `min > max`, `min` is NaN, or `max` is NaN.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(clamp)]
-    /// assert!((-3.0f64).clamp(-2.0f64, 1.0f64) == -2.0f64);
-    /// assert!((0.0f64).clamp(-2.0f64, 1.0f64) == 0.0f64);
-    /// assert!((2.0f64).clamp(-2.0f64, 1.0f64) == 1.0f64);
-    /// assert!((std::f64::NAN).clamp(-2.0f64, 1.0f64).is_nan());
+    /// assert!((-3.0f64).clamp(-2.0, 1.0) == -2.0);
+    /// assert!((0.0f64).clamp(-2.0, 1.0) == 0.0);
+    /// assert!((2.0f64).clamp(-2.0, 1.0) == 1.0);
+    /// assert!((std::f64::NAN).clamp(-2.0, 1.0).is_nan());
     /// ```
     #[unstable(feature = "clamp", issue = "44095")]
     #[inline]
diff --git a/src/libstd/sys/cloudabi/time.rs b/src/libstd/sys/cloudabi/time.rs
index d7502c61eff..49a234e1158 100644
--- a/src/libstd/sys/cloudabi/time.rs
+++ b/src/libstd/sys/cloudabi/time.rs
@@ -33,11 +33,9 @@ impl Instant {
         Instant { t: 0 }
     }
 
-    pub fn sub_instant(&self, other: &Instant) -> Duration {
-        let diff = self.t
-            .checked_sub(other.t)
-            .expect("second instant is later than self");
-        Duration::new(diff / NSEC_PER_SEC, (diff % NSEC_PER_SEC) as u32)
+    pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+        let diff = self.t.checked_sub(other.t)?;
+        Some(Duration::new(diff / NSEC_PER_SEC, (diff % NSEC_PER_SEC) as u32))
     }
 
     pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
diff --git a/src/libstd/sys/redox/time.rs b/src/libstd/sys/redox/time.rs
index 9db3e85ca9c..881ad5c0aeb 100644
--- a/src/libstd/sys/redox/time.rs
+++ b/src/libstd/sys/redox/time.rs
@@ -137,10 +137,8 @@ impl Instant {
         false
     }
 
-    pub fn sub_instant(&self, other: &Instant) -> Duration {
-        self.t.sub_timespec(&other.t).unwrap_or_else(|_| {
-            panic!("specified instant was later than self")
-        })
+    pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+        self.t.sub_timespec(&other.t).ok()
     }
 
     pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
diff --git a/src/libstd/sys/sgx/time.rs b/src/libstd/sys/sgx/time.rs
index e4f789c3e36..4659f7ba71f 100644
--- a/src/libstd/sys/sgx/time.rs
+++ b/src/libstd/sys/sgx/time.rs
@@ -14,8 +14,8 @@ impl Instant {
         Instant(usercalls::insecure_time())
     }
 
-    pub fn sub_instant(&self, other: &Instant) -> Duration {
-        self.0 - other.0
+    pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+        self.0.checked_sub(other.0)
     }
 
     pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
diff --git a/src/libstd/sys/unix/time.rs b/src/libstd/sys/unix/time.rs
index cbb0615911a..6b5a89aee7d 100644
--- a/src/libstd/sys/unix/time.rs
+++ b/src/libstd/sys/unix/time.rs
@@ -149,12 +149,11 @@ mod inner {
             true
         }
 
-        pub fn sub_instant(&self, other: &Instant) -> Duration {
+        pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+            let diff = self.t.checked_sub(other.t)?;
             let info = info();
-            let diff = self.t.checked_sub(other.t)
-                           .expect("second instant is later than self");
             let nanos = mul_div_u64(diff, info.numer as u64, info.denom as u64);
-            Duration::new(nanos / NSEC_PER_SEC, (nanos % NSEC_PER_SEC) as u32)
+            Some(Duration::new(nanos / NSEC_PER_SEC, (nanos % NSEC_PER_SEC) as u32))
         }
 
         pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
@@ -285,10 +284,8 @@ mod inner {
             false // last clause, used so `||` is always trailing above
         }
 
-        pub fn sub_instant(&self, other: &Instant) -> Duration {
-            self.t.sub_timespec(&other.t).unwrap_or_else(|_| {
-                panic!("specified instant was later than self")
-            })
+        pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+            self.t.sub_timespec(&other.t).ok()
         }
 
         pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
diff --git a/src/libstd/sys/wasm/time.rs b/src/libstd/sys/wasm/time.rs
index c1228a1b75e..3f71461eea4 100644
--- a/src/libstd/sys/wasm/time.rs
+++ b/src/libstd/sys/wasm/time.rs
@@ -22,8 +22,8 @@ impl Instant {
         false
     }
 
-    pub fn sub_instant(&self, other: &Instant) -> Duration {
-        self.0 - other.0
+    pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+        self.0.checked_sub(other.0)
     }
 
     pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
diff --git a/src/libstd/sys/windows/time.rs b/src/libstd/sys/windows/time.rs
index 2c99bca7009..aa53f1194fd 100644
--- a/src/libstd/sys/windows/time.rs
+++ b/src/libstd/sys/windows/time.rs
@@ -49,17 +49,17 @@ impl Instant {
         Instant { t: Duration::from_secs(0) }
     }
 
-    pub fn sub_instant(&self, other: &Instant) -> Duration {
+    pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
         // On windows there's a threshold below which we consider two timestamps
         // equivalent due to measurement error. For more details + doc link,
         // check the docs on epsilon.
         let epsilon =
             perf_counter::PerformanceCounterInstant::epsilon();
         if other.t > self.t && other.t - self.t <= epsilon {
-            return Duration::new(0, 0)
+            Some(Duration::new(0, 0))
+        } else {
+            self.t.checked_sub(other.t)
         }
-        self.t.checked_sub(other.t)
-              .expect("specified instant was later than self")
     }
 
     pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
diff --git a/src/libstd/time.rs b/src/libstd/time.rs
index 4c86f70ad87..ab1a43d6672 100644
--- a/src/libstd/time.rs
+++ b/src/libstd/time.rs
@@ -212,7 +212,7 @@ impl Instant {
     /// ```
     #[stable(feature = "time2", since = "1.8.0")]
     pub fn duration_since(&self, earlier: Instant) -> Duration {
-        self.0.sub_instant(&earlier.0)
+        self.0.checked_sub_instant(&earlier.0).expect("supplied instant is later than self")
     }
 
     /// Returns the amount of time elapsed from another instant to this one,
@@ -233,11 +233,7 @@ impl Instant {
     /// ```
     #[unstable(feature = "checked_duration_since", issue = "58402")]
     pub fn checked_duration_since(&self, earlier: Instant) -> Option<Duration> {
-        if self >= &earlier {
-            Some(self.0.sub_instant(&earlier.0))
-        } else {
-            None
-        }
+        self.0.checked_sub_instant(&earlier.0)
     }
 
     /// Returns the amount of time elapsed from another instant to this one,
@@ -664,20 +660,23 @@ mod tests {
 
     #[test]
     #[should_panic]
-    fn instant_duration_panic() {
+    fn instant_duration_since_panic() {
         let a = Instant::now();
         (a - Duration::new(1, 0)).duration_since(a);
     }
 
     #[test]
-    fn checked_instant_duration_nopanic() {
-        let a = Instant::now();
-        let ret = (a - Duration::new(1, 0)).checked_duration_since(a);
-        assert_eq!(ret, None);
+    fn instant_checked_duration_since_nopanic() {
+        let now = Instant::now();
+        let earlier = now - Duration::new(1, 0);
+        let later = now + Duration::new(1, 0);
+        assert_eq!(earlier.checked_duration_since(now), None);
+        assert_eq!(later.checked_duration_since(now), Some(Duration::new(1, 0)));
+        assert_eq!(now.checked_duration_since(now), Some(Duration::new(0, 0)));
     }
 
     #[test]
-    fn saturating_instant_duration_nopanic() {
+    fn instant_saturating_duration_since_nopanic() {
         let a = Instant::now();
         let ret = (a - Duration::new(1, 0)).saturating_duration_since(a);
         assert_eq!(ret, Duration::new(0,0));