Auto merge of #51859 - kennytm:rollup, r=kennytm

Rollup of 7 pull requests

Successful merges:

 - #49987 (Add str::split_ascii_whitespace.)
 - #50342 (Document round-off error in `.mod_euc()`-method, see issue #50179)
 - #51658 (Only do sanity check with debug assertions on)
 - #51799 (Lower case some feature gate error messages)
 - #51800 (Add a compiletest header for edition)
 - #51824 (Fix the error reference for LocalKey::try_with)
 - #51842 (Document that Layout::from_size_align does not allow align=0)

Failed merges:

r? @ghost

src/liballoc/lib.rs

@@ -108,6 +108,7 @@
 #![cfg_attr(stage0, feature(repr_transparent))]
 #![feature(rustc_attrs)]
 #![feature(specialization)]
+#![feature(split_ascii_whitespace)]
 #![feature(staged_api)]
 #![feature(str_internals)]
 #![feature(trusted_len)]

src/liballoc/str.rs

@@ -78,6 +78,8 @@ pub use core::str::SplitWhitespace;
 pub use core::str::pattern;
 #[stable(feature = "encode_utf16", since = "1.8.0")]
 pub use core::str::EncodeUtf16;
+#[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+pub use core::str::SplitAsciiWhitespace;
 
 #[unstable(feature = "slice_concat_ext",
            reason = "trait should not have to exist",

src/libcore/alloc.rs

@@ -67,6 +67,8 @@ impl Layout {
     /// or returns `LayoutErr` if either of the following conditions
     /// are not met:
     ///
+    /// * `align` must not be zero,
+    ///
     /// * `align` must be a power of two,
     ///
     /// * `size`, when rounded up to the nearest multiple of `align`,

src/libcore/str/mod.rs

@@ -21,7 +21,7 @@ use char;
 use fmt;
 use iter::{Map, Cloned, FusedIterator, TrustedLen, Filter};
 use iter_private::TrustedRandomAccess;
-use slice::{self, SliceIndex};
+use slice::{self, SliceIndex, Split as SliceSplit};
 use mem;
 
 pub mod pattern;
@@ -2722,7 +2722,10 @@ impl str {
     /// the original string slice, separated by any amount of whitespace.
     ///
     /// 'Whitespace' is defined according to the terms of the Unicode Derived
-    /// Core Property `White_Space`.
+    /// Core Property `White_Space`. If you only want to split on ASCII whitespace
+    /// instead, use [`split_ascii_whitespace`].
+    ///
+    /// [`split_ascii_whitespace`]: #method.split_ascii_whitespace
     ///
     /// # Examples
     ///
@@ -2756,6 +2759,53 @@ impl str {
         SplitWhitespace { inner: self.split(IsWhitespace).filter(IsNotEmpty) }
     }
 
+    /// Split a string slice by ASCII whitespace.
+    ///
+    /// The iterator returned will return string slices that are sub-slices of
+    /// the original string slice, separated by any amount of ASCII whitespace.
+    ///
+    /// To split by Unicode `Whitespace` instead, use [`split_whitespace`].
+    ///
+    /// [`split_whitespace`]: #method.split_whitespace
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// #![feature(split_ascii_whitespace)]
+    /// let mut iter = "A few words".split_ascii_whitespace();
+    ///
+    /// assert_eq!(Some("A"), iter.next());
+    /// assert_eq!(Some("few"), iter.next());
+    /// assert_eq!(Some("words"), iter.next());
+    ///
+    /// assert_eq!(None, iter.next());
+    /// ```
+    ///
+    /// All kinds of ASCII whitespace are considered:
+    ///
+    /// ```
+    /// let mut iter = " Mary   had\ta little  \n\t lamb".split_whitespace();
+    /// assert_eq!(Some("Mary"), iter.next());
+    /// assert_eq!(Some("had"), iter.next());
+    /// assert_eq!(Some("a"), iter.next());
+    /// assert_eq!(Some("little"), iter.next());
+    /// assert_eq!(Some("lamb"), iter.next());
+    ///
+    /// assert_eq!(None, iter.next());
+    /// ```
+    #[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+    #[inline]
+    pub fn split_ascii_whitespace(&self) -> SplitAsciiWhitespace {
+        let inner = self
+            .as_bytes()
+            .split(IsAsciiWhitespace)
+            .filter(IsNotEmpty)
+            .map(UnsafeBytesToStr);
+        SplitAsciiWhitespace { inner }
+    }
+
     /// An iterator over the lines of a string, as string slices.
     ///
     /// Lines are ended with either a newline (`\n`) or a carriage return with
@@ -3895,6 +3945,20 @@ pub struct SplitWhitespace<'a> {
     inner: Filter<Split<'a, IsWhitespace>, IsNotEmpty>,
 }
 
+/// An iterator over the non-ASCII-whitespace substrings of a string,
+/// separated by any amount of ASCII whitespace.
+///
+/// This struct is created by the [`split_ascii_whitespace`] method on [`str`].
+/// See its documentation for more.
+///
+/// [`split_ascii_whitespace`]: ../../std/primitive.str.html#method.split_ascii_whitespace
+/// [`str`]: ../../std/primitive.str.html
+#[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+#[derive(Clone, Debug)]
+pub struct SplitAsciiWhitespace<'a> {
+    inner: Map<Filter<SliceSplit<'a, u8, IsAsciiWhitespace>, IsNotEmpty>, UnsafeBytesToStr>,
+}
+
 #[derive(Clone)]
 struct IsWhitespace;
 
@@ -3914,37 +3978,98 @@ impl FnMut<(char, )> for IsWhitespace {
     }
 }
 
+#[derive(Clone)]
+struct IsAsciiWhitespace;
+
+impl<'a> FnOnce<(&'a u8, )> for IsAsciiWhitespace {
+    type Output = bool;
+
+    #[inline]
+    extern "rust-call" fn call_once(mut self, arg: (&u8, )) -> bool {
+        self.call_mut(arg)
+    }
+}
+
+impl<'a> FnMut<(&'a u8, )> for IsAsciiWhitespace {
+    #[inline]
+    extern "rust-call" fn call_mut(&mut self, arg: (&u8, )) -> bool {
+        arg.0.is_ascii_whitespace()
+    }
+}
+
 #[derive(Clone)]
 struct IsNotEmpty;
 
 impl<'a, 'b> FnOnce<(&'a &'b str, )> for IsNotEmpty {
     type Output = bool;
 
     #[inline]
-    extern "rust-call" fn call_once(mut self, arg: (&&str, )) -> bool {
+    extern "rust-call" fn call_once(mut self, arg: (&'a &'b str, )) -> bool {
         self.call_mut(arg)
     }
 }
 
 impl<'a, 'b> FnMut<(&'a &'b str, )> for IsNotEmpty {
     #[inline]
-    extern "rust-call" fn call_mut(&mut self, arg: (&&str, )) -> bool {
+    extern "rust-call" fn call_mut(&mut self, arg: (&'a &'b str, )) -> bool {
+        !arg.0.is_empty()
+    }
+}
+
+impl<'a, 'b> FnOnce<(&'a &'b [u8], )> for IsNotEmpty {
+    type Output = bool;
+
+    #[inline]
+    extern "rust-call" fn call_once(mut self, arg: (&'a &'b [u8], )) -> bool {
+        self.call_mut(arg)
+    }
+}
+
+impl<'a, 'b> FnMut<(&'a &'b [u8], )> for IsNotEmpty {
+    #[inline]
+    extern "rust-call" fn call_mut(&mut self, arg: (&'a &'b [u8], )) -> bool {
         !arg.0.is_empty()
     }
 }
 
+#[derive(Clone)]
+struct UnsafeBytesToStr;
+
+impl<'a> FnOnce<(&'a [u8], )> for UnsafeBytesToStr {
+    type Output = &'a str;
+
+    #[inline]
+    extern "rust-call" fn call_once(mut self, arg: (&'a [u8], )) -> &'a str {
+        self.call_mut(arg)
+    }
+}
+
+impl<'a> FnMut<(&'a [u8], )> for UnsafeBytesToStr {
+    #[inline]
+    extern "rust-call" fn call_mut(&mut self, arg: (&'a [u8], )) -> &'a str {
+        unsafe { from_utf8_unchecked(arg.0) }
+    }
+}
+
 
 #[stable(feature = "split_whitespace", since = "1.1.0")]
 impl<'a> Iterator for SplitWhitespace<'a> {
     type Item = &'a str;
 
+    #[inline]
     fn next(&mut self) -> Option<&'a str> {
         self.inner.next()
     }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
 }
 
 #[stable(feature = "split_whitespace", since = "1.1.0")]
 impl<'a> DoubleEndedIterator for SplitWhitespace<'a> {
+    #[inline]
     fn next_back(&mut self) -> Option<&'a str> {
         self.inner.next_back()
     }
@@ -3953,6 +4078,32 @@ impl<'a> DoubleEndedIterator for SplitWhitespace<'a> {
 #[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for SplitWhitespace<'a> {}
 
+#[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+impl<'a> Iterator for SplitAsciiWhitespace<'a> {
+    type Item = &'a str;
+
+    #[inline]
+    fn next(&mut self) -> Option<&'a str> {
+        self.inner.next()
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
+}
+
+#[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+impl<'a> DoubleEndedIterator for SplitAsciiWhitespace<'a> {
+    #[inline]
+    fn next_back(&mut self) -> Option<&'a str> {
+        self.inner.next_back()
+    }
+}
+
+#[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+impl<'a> FusedIterator for SplitAsciiWhitespace<'a> {}
+
 /// An iterator of [`u16`] over the string encoded as UTF-16.
 ///
 /// [`u16`]: ../../std/primitive.u16.html

src/libcore/tests/num/mod.rs

@@ -574,6 +574,25 @@ macro_rules! test_float {
             assert_eq!((-9.0 as $fty).max($nan), -9.0);
             assert!(($nan as $fty).max($nan).is_nan());
         }
+        #[test]
+        fn mod_euc() {
+            let a: $fty = 42.0;
+            assert!($inf.mod_euc(a).is_nan());
+            assert_eq!(a.mod_euc($inf), a);
+            assert!(a.mod_euc($nan).is_nan());
+            assert!($inf.mod_euc($inf).is_nan());
+            assert!($inf.mod_euc($nan).is_nan());
+            assert!($nan.mod_euc($inf).is_nan());
+        }
+        #[test]
+        fn div_euc() {
+            let a: $fty = 42.0;
+            assert_eq!(a.div_euc($inf), 0.0);
+            assert!(a.div_euc($nan).is_nan());
+            assert!($inf.div_euc($inf).is_nan());
+            assert!($inf.div_euc($nan).is_nan());
+            assert!($nan.div_euc($inf).is_nan());
+        }
     } }
 }
 

src/librustc/traits/query/normalize.rs

@@ -124,10 +124,10 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for QueryNormalizer<'cx, 'gcx, 'tcx
                         let concrete_ty = generic_ty.subst(self.tcx(), substs);
                         self.anon_depth += 1;
                         if concrete_ty == ty {
-                            println!("generic_ty: {:#?}", generic_ty);
-                            println!("substs {:#?}", substs);
+                            bug!("infinite recursion generic_ty: {:#?}, substs: {:#?}, \
+                                  concrete_ty: {:#?}, ty: {:#?}", generic_ty, substs, concrete_ty,
+                                  ty);
                         }
-                        assert_ne!(concrete_ty, ty, "infinite recursion");
                         let folded_ty = self.fold_ty(concrete_ty);
                         self.anon_depth -= 1;
                         folded_ty

src/libstd/f32.rs

@@ -254,7 +254,14 @@ impl f32 {
 
     /// Calculates the Euclidean modulo (self mod rhs), which is never negative.
     ///
-    /// In particular, the result `n` satisfies `0 <= n < rhs.abs()`.
+    /// In particular, the return value `r` satisfies `0.0 <= r < rhs.abs()` in
+    /// most cases. However, due to a floating point round-off error it can
+    /// result in `r == rhs.abs()`, violating the mathematical definition, if
+    /// `self` is much smaller than `rhs.abs()` in magnitude and `self < 0.0`.
+    /// This result is not an element of the function's codomain, but it is the
+    /// closest floating point number in the real numbers and thus fulfills the
+    /// property `self == self.div_euc(rhs) * rhs + self.mod_euc(rhs)`
+    /// approximatively.
     ///
     /// # Examples
     ///
@@ -266,6 +273,8 @@ impl f32 {
     /// assert_eq!((-a).mod_euc(b), 1.0);
     /// assert_eq!(a.mod_euc(-b), 3.0);
     /// assert_eq!((-a).mod_euc(-b), 1.0);
+    /// // limitation due to round-off error
+    /// assert!((-std::f32::EPSILON).mod_euc(3.0) != 0.0);
     /// ```
     #[inline]
     #[unstable(feature = "euclidean_division", issue = "49048")]

src/libstd/f64.rs

@@ -230,7 +230,14 @@ impl f64 {
 
     /// Calculates the Euclidean modulo (self mod rhs), which is never negative.
     ///
-    /// In particular, the result `n` satisfies `0 <= n < rhs.abs()`.
+    /// In particular, the return value `r` satisfies `0.0 <= r < rhs.abs()` in
+    /// most cases.  However, due to a floating point round-off error it can
+    /// result in `r == rhs.abs()`, violating the mathematical definition, if
+    /// `self` is much smaller than `rhs.abs()` in magnitude and `self < 0.0`.
+    /// This result is not an element of the function's codomain, but it is the
+    /// closest floating point number in the real numbers and thus fulfills the
+    /// property `self == self.div_euc(rhs) * rhs + self.mod_euc(rhs)`
+    /// approximatively.
     ///
     /// # Examples
     ///
@@ -242,6 +249,8 @@ impl f64 {
     /// assert_eq!((-a).mod_euc(b), 1.0);
     /// assert_eq!(a.mod_euc(-b), 3.0);
     /// assert_eq!((-a).mod_euc(-b), 1.0);
+    /// // limitation due to round-off error
+    /// assert!((-std::f64::EPSILON).mod_euc(3.0) != 0.0);
     /// ```
     #[inline]
     #[unstable(feature = "euclidean_division", issue = "49048")]

src/libstd/thread/local.rs

@@ -276,7 +276,7 @@ impl<T: 'static> LocalKey<T> {
     ///
     /// This will lazily initialize the value if this thread has not referenced
     /// this key yet. If the key has been destroyed (which may happen if this is called
-    /// in a destructor), this function will return a `ThreadLocalError`.
+    /// in a destructor), this function will return an [`AccessError`](struct.AccessError.html).
     ///
     /// # Panics
     ///

src/libsyntax/feature_gate.rs

@@ -1359,17 +1359,17 @@ pub const EXPLAIN_LITERAL_MATCHER: &'static str =
     ":literal fragment specifier is experimental and subject to change";
 
 pub const EXPLAIN_UNSIZED_TUPLE_COERCION: &'static str =
-    "Unsized tuple coercion is not stable enough for use and is subject to change";
+    "unsized tuple coercion is not stable enough for use and is subject to change";
 
 pub const EXPLAIN_MACRO_AT_MOST_ONCE_REP: &'static str =
-    "Using the `?` macro Kleene operator for \"at most one\" repetition is unstable";
+    "using the `?` macro Kleene operator for \"at most one\" repetition is unstable";
 
 pub const EXPLAIN_MACROS_IN_EXTERN: &'static str =
-    "Macro invocations in `extern {}` blocks are experimental.";
+    "macro invocations in `extern {}` blocks are experimental.";
 
 // mention proc-macros when enabled
 pub const EXPLAIN_PROC_MACROS_IN_EXTERN: &'static str =
-    "Macro and proc-macro invocations in `extern {}` blocks are experimental.";
+    "macro and proc-macro invocations in `extern {}` blocks are experimental.";
 
 struct PostExpansionVisitor<'a> {
     context: &'a Context<'a>,

src/test/compile-fail-fulldeps/proc-macro/macros-in-extern.rs

@@ -26,13 +26,13 @@ fn main() {
 #[link(name = "rust_test_helpers", kind = "static")]
 extern {
     #[no_output]
-    //~^ ERROR Macro and proc-macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro and proc-macro invocations in `extern {}` blocks are experimental.
     fn some_definitely_unknown_symbol_which_should_be_removed();
 
     #[nop_attr]
-    //~^ ERROR Macro and proc-macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro and proc-macro invocations in `extern {}` blocks are experimental.
     fn rust_get_test_int() -> isize;
 
     emit_input!(fn rust_dbg_extern_identity_u32(arg: u32) -> u32;);
-    //~^ ERROR Macro and proc-macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro and proc-macro invocations in `extern {}` blocks are experimental.
 }