Auto merge of #70617 - Centril:rollup-063ycso, r=Centril

Rollup of 9 pull requests

Successful merges:

 - #69784 (Optimize strip_prefix and strip_suffix with str patterns)
 - #70548 (Add long error code for error E0226)
 - #70555 (resolve, `try_resolve_as_non_binding`: use `delay_span_bug` due to parser recovery)
 - #70561 (remove obsolete comment)
 - #70562 (infer array len from pattern)
 - #70585 (std: Fix over-aligned allocations on wasm32-wasi)
 - #70587 (Add `Rust` to the code snippet)
 - #70588 (Fix incorrect documentation for `str::{split_at, split_at_mut}`)
 - #70613 (more clippy fixes)

Failed merges:

r? @ghost

Author: bors

.github/ISSUE_TEMPLATE/ice.md

@@ -14,7 +14,7 @@ http://blog.pnkfx.org/blog/2019/11/18/rust-bug-minimization-patterns/
 
 ### Code
 
-```
+```Rust
 <code>
 ```
 

src/liballoc/string.rs

@@ -1849,6 +1849,21 @@ impl<'a, 'b> Pattern<'a> for &'b String {
     fn is_prefix_of(self, haystack: &'a str) -> bool {
         self[..].is_prefix_of(haystack)
     }
+
+    #[inline]
+    fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str> {
+        self[..].strip_prefix_of(haystack)
+    }
+
+    #[inline]
+    fn is_suffix_of(self, haystack: &'a str) -> bool {
+        self[..].is_suffix_of(haystack)
+    }
+
+    #[inline]
+    fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str> {
+        self[..].strip_suffix_of(haystack)
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/libcore/str/mod.rs

@@ -9,7 +9,7 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 use self::pattern::Pattern;
-use self::pattern::{DoubleEndedSearcher, ReverseSearcher, SearchStep, Searcher};
+use self::pattern::{DoubleEndedSearcher, ReverseSearcher, Searcher};
 
 use crate::char;
 use crate::fmt::{self, Write};
@@ -2642,7 +2642,7 @@ impl str {
     /// # Panics
     ///
     /// Panics if `mid` is not on a UTF-8 code point boundary, or if it is
-    /// beyond the last code point of the string slice.
+    /// past the end of the last code point of the string slice.
     ///
     /// # Examples
     ///
@@ -2683,7 +2683,7 @@ impl str {
     /// # Panics
     ///
     /// Panics if `mid` is not on a UTF-8 code point boundary, or if it is
-    /// beyond the last code point of the string slice.
+    /// past the end of the last code point of the string slice.
     ///
     /// # Examples
     ///
@@ -3986,26 +3986,15 @@ impl str {
     /// ```
     /// #![feature(str_strip)]
     ///
-    /// assert_eq!("foobar".strip_prefix("foo"), Some("bar"));
-    /// assert_eq!("foobar".strip_prefix("bar"), None);
+    /// assert_eq!("foo:bar".strip_prefix("foo:"), Some("bar"));
+    /// assert_eq!("foo:bar".strip_prefix("bar"), None);
     /// assert_eq!("foofoo".strip_prefix("foo"), Some("foo"));
     /// ```
     #[must_use = "this returns the remaining substring as a new slice, \
                   without modifying the original"]
     #[unstable(feature = "str_strip", reason = "newly added", issue = "67302")]
     pub fn strip_prefix<'a, P: Pattern<'a>>(&'a self, prefix: P) -> Option<&'a str> {
-        let mut matcher = prefix.into_searcher(self);
-        if let SearchStep::Match(start, len) = matcher.next() {
-            debug_assert_eq!(
-                start, 0,
-                "The first search step from Searcher \
-                 must include the first character"
-            );
-            // SAFETY: `Searcher` is known to return valid indices.
-            unsafe { Some(self.get_unchecked(len..)) }
-        } else {
-            None
-        }
+        prefix.strip_prefix_of(self)
     }
 
     /// Returns a string slice with the suffix removed.
@@ -4020,8 +4009,8 @@ impl str {
     ///
     /// ```
     /// #![feature(str_strip)]
-    /// assert_eq!("barfoo".strip_suffix("foo"), Some("bar"));
-    /// assert_eq!("barfoo".strip_suffix("bar"), None);
+    /// assert_eq!("bar:foo".strip_suffix(":foo"), Some("bar"));
+    /// assert_eq!("bar:foo".strip_suffix("bar"), None);
     /// assert_eq!("foofoo".strip_suffix("foo"), Some("foo"));
     /// ```
     #[must_use = "this returns the remaining substring as a new slice, \
@@ -4032,19 +4021,7 @@ impl str {
         P: Pattern<'a>,
         <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
     {
-        let mut matcher = suffix.into_searcher(self);
-        if let SearchStep::Match(start, end) = matcher.next_back() {
-            debug_assert_eq!(
-                end,
-                self.len(),
-                "The first search step from ReverseSearcher \
-                 must include the last character"
-            );
-            // SAFETY: `Searcher` is known to return valid indices.
-            unsafe { Some(self.get_unchecked(..start)) }
-        } else {
-            None
-        }
+        suffix.strip_suffix_of(self)
     }
 
     /// Returns a string slice with all suffixes that match a pattern

src/libcore/str/pattern.rs

@@ -47,6 +47,22 @@ pub trait Pattern<'a>: Sized {
         matches!(self.into_searcher(haystack).next(), SearchStep::Match(0, _))
     }
 
+    /// Removes the pattern from the front of haystack, if it matches.
+    #[inline]
+    fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str> {
+        if let SearchStep::Match(start, len) = self.into_searcher(haystack).next() {
+            debug_assert_eq!(
+                start, 0,
+                "The first search step from Searcher \
+                 must include the first character"
+            );
+            // SAFETY: `Searcher` is known to return valid indices.
+            unsafe { Some(haystack.get_unchecked(len..)) }
+        } else {
+            None
+        }
+    }
+
     /// Checks whether the pattern matches at the back of the haystack
     #[inline]
     fn is_suffix_of(self, haystack: &'a str) -> bool
@@ -55,6 +71,26 @@ pub trait Pattern<'a>: Sized {
     {
         matches!(self.into_searcher(haystack).next_back(), SearchStep::Match(_, j) if haystack.len() == j)
     }
+
+    /// Removes the pattern from the back of haystack, if it matches.
+    #[inline]
+    fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str>
+    where
+        Self::Searcher: ReverseSearcher<'a>,
+    {
+        if let SearchStep::Match(start, end) = self.into_searcher(haystack).next_back() {
+            debug_assert_eq!(
+                end,
+                haystack.len(),
+                "The first search step from ReverseSearcher \
+                 must include the last character"
+            );
+            // SAFETY: `Searcher` is known to return valid indices.
+            unsafe { Some(haystack.get_unchecked(..start)) }
+        } else {
+            None
+        }
+    }
 }
 
 // Searcher
@@ -448,13 +484,26 @@ impl<'a> Pattern<'a> for char {
         self.encode_utf8(&mut [0u8; 4]).is_prefix_of(haystack)
     }
 
+    #[inline]
+    fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str> {
+        self.encode_utf8(&mut [0u8; 4]).strip_prefix_of(haystack)
+    }
+
     #[inline]
     fn is_suffix_of(self, haystack: &'a str) -> bool
     where
         Self::Searcher: ReverseSearcher<'a>,
     {
         self.encode_utf8(&mut [0u8; 4]).is_suffix_of(haystack)
     }
+
+    #[inline]
+    fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str>
+    where
+        Self::Searcher: ReverseSearcher<'a>,
+    {
+        self.encode_utf8(&mut [0u8; 4]).strip_suffix_of(haystack)
+    }
 }
 
 /////////////////////////////////////////////////////////////////////////////
@@ -569,13 +618,26 @@ macro_rules! pattern_methods {
             ($pmap)(self).is_prefix_of(haystack)
         }
 
+        #[inline]
+        fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str> {
+            ($pmap)(self).strip_prefix_of(haystack)
+        }
+
         #[inline]
         fn is_suffix_of(self, haystack: &'a str) -> bool
         where
             $t: ReverseSearcher<'a>,
         {
             ($pmap)(self).is_suffix_of(haystack)
         }
+
+        #[inline]
+        fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str>
+        where
+            $t: ReverseSearcher<'a>,
+        {
+            ($pmap)(self).strip_suffix_of(haystack)
+        }
     };
 }
 
@@ -715,11 +777,34 @@ impl<'a, 'b> Pattern<'a> for &'b str {
         haystack.as_bytes().starts_with(self.as_bytes())
     }
 
+    /// Removes the pattern from the front of haystack, if it matches.
+    #[inline]
+    fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str> {
+        if self.is_prefix_of(haystack) {
+            // SAFETY: prefix was just verified to exist.
+            unsafe { Some(haystack.get_unchecked(self.as_bytes().len()..)) }
+        } else {
+            None
+        }
+    }
+
     /// Checks whether the pattern matches at the back of the haystack
     #[inline]
     fn is_suffix_of(self, haystack: &'a str) -> bool {
         haystack.as_bytes().ends_with(self.as_bytes())
     }
+
+    /// Removes the pattern from the back of haystack, if it matches.
+    #[inline]
+    fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str> {
+        if self.is_suffix_of(haystack) {
+            let i = haystack.len() - self.as_bytes().len();
+            // SAFETY: suffix was just verified to exist.
+            unsafe { Some(haystack.get_unchecked(..i)) }
+        } else {
+            None
+        }
+    }
 }
 
 /////////////////////////////////////////////////////////////////////////////

src/librustc_error_codes/error_codes.rs

@@ -119,6 +119,7 @@ E0222: include_str!("./error_codes/E0222.md"),
 E0223: include_str!("./error_codes/E0223.md"),
 E0224: include_str!("./error_codes/E0224.md"),
 E0225: include_str!("./error_codes/E0225.md"),
+E0226: include_str!("./error_codes/E0226.md"),
 E0229: include_str!("./error_codes/E0229.md"),
 E0230: include_str!("./error_codes/E0230.md"),
 E0231: include_str!("./error_codes/E0231.md"),
@@ -475,7 +476,6 @@ E0751: include_str!("./error_codes/E0751.md"),
 //  E0217, // ambiguous associated type, defined in multiple supertraits
 //  E0218, // no associated type defined
 //  E0219, // associated type defined in higher-ranked supertrait
-    E0226, // only a single explicit lifetime bound is permitted
     E0227, // ambiguous lifetime bound, explicit lifetime bound required
     E0228, // explicit lifetime bound required
 //  E0233,

src/librustc_error_codes/error_codes/E0226.md

@@ -0,0 +1,21 @@
+More than one explicit lifetime bound was used on a trait object.
+
+Example of erroneous code:
+
+```compile_fail,E0226
+trait Foo {}
+
+type T<'a, 'b> = dyn Foo + 'a + 'b; // error: Trait object `arg` has two
+                                    //        lifetime bound, 'a and 'b.
+```
+
+Here `T` is a trait object with two explicit lifetime bounds, 'a and 'b.
+
+Only a single explicit lifetime bound is permitted on trait objects.
+To fix this error, consider removing one of the lifetime bounds:
+
+```
+trait Foo {}
+
+type T<'a> = dyn Foo + 'a;
+```

src/librustc_error_codes/error_codes/E0730.md

@@ -7,8 +7,8 @@ Example of erroneous code:
 
 fn is_123<const N: usize>(x: [u32; N]) -> bool {
     match x {
-        [1, 2, 3] => true, // error: cannot pattern-match on an
-                           //        array without a fixed length
+        [1, 2, ..] => true, // error: cannot pattern-match on an
+                            //        array without a fixed length
         _ => false
     }
 }

src/librustc_interface/passes.rs

@@ -711,7 +711,7 @@ impl<'tcx> QueryContext<'tcx> {
     }
 
     pub fn print_stats(&mut self) {
-        self.enter(|tcx| ty::query::print_stats(tcx))
+        self.enter(ty::query::print_stats)
     }
 }
 

src/librustc_mir/interpret/terminator.rs

@@ -30,7 +30,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 trace!("SwitchInt({:?})", *discr);
 
                 // Branch to the `otherwise` case by default, if no match is found.
-                assert!(targets.len() > 0);
+                assert!(!targets.is_empty());
                 let mut target_block = targets[targets.len() - 1];
 
                 for (index, &const_int) in values.iter().enumerate() {

src/librustc_parse/lexer/mod.rs

@@ -93,9 +93,6 @@ impl<'a> StringReader<'a> {
     }
 
     /// Returns the next token, including trivia like whitespace or comments.
-    ///
-    /// `Err(())` means that some errors were encountered, which can be
-    /// retrieved using `buffer_fatal_errors`.
     pub fn next_token(&mut self) -> Token {
         let start_src_index = self.src_index(self.pos);
         let text: &str = &self.src[start_src_index..self.end_src_index];

src/librustc_resolve/late.rs

@@ -1536,20 +1536,18 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         let is_syntactic_ambiguity = !has_sub && bm == BindingMode::ByValue(Mutability::Not);
 
         match res {
-            Res::Def(DefKind::Ctor(_, CtorKind::Const), _)
-            | Res::Def(DefKind::Const, _)
-            | Res::Def(DefKind::ConstParam, _)
-                if is_syntactic_ambiguity =>
-            {
+            Res::SelfCtor(_) // See #70549.
+            | Res::Def(
+                DefKind::Ctor(_, CtorKind::Const) | DefKind::Const | DefKind::ConstParam,
+                _,
+            ) if is_syntactic_ambiguity => {
                 // Disambiguate in favor of a unit struct/variant or constant pattern.
                 if let Some(binding) = binding {
                     self.r.record_use(ident, ValueNS, binding, false);
                 }
                 Some(res)
             }
-            Res::Def(DefKind::Ctor(..), _)
-            | Res::Def(DefKind::Const, _)
-            | Res::Def(DefKind::Static, _) => {
+            Res::Def(DefKind::Ctor(..) | DefKind::Const | DefKind::Static, _) => {
                 // This is unambiguously a fresh binding, either syntactically
                 // (e.g., `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
                 // to something unusable as a pattern (e.g., constructor function),
@@ -1572,7 +1570,7 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             _ => span_bug!(
                 ident.span,
                 "unexpected resolution for an identifier in pattern: {:?}",
-                res
+                res,
             ),
         }
     }

src/librustc_resolve/lib.rs

@@ -10,6 +10,7 @@
 #![feature(bool_to_option)]
 #![feature(crate_visibility_modifier)]
 #![feature(nll)]
+#![feature(or_patterns)]
 #![recursion_limit = "256"]
 
 pub use rustc_hir::def::{Namespace, PerNS};

src/librustc_save_analysis/lib.rs

@@ -591,7 +591,7 @@ impl<'l, 'tcx> SaveContext<'l, 'tcx> {
                 Some(Data::RefData(Ref {
                     kind: RefKind::Function,
                     span,
-                    ref_id: def_id.or(decl_id).map(id_from_def_id).unwrap_or_else(|| null_id()),
+                    ref_id: def_id.or(decl_id).map(id_from_def_id).unwrap_or_else(null_id),
                 }))
             }
             ast::ExprKind::Path(_, ref path) => {

src/librustc_session/config.rs

@@ -1650,7 +1650,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
 
     check_thread_count(&debugging_opts, error_format);
 
-    let incremental = cg.incremental.as_ref().map(|m| PathBuf::from(m));
+    let incremental = cg.incremental.as_ref().map(PathBuf::from);
 
     if debugging_opts.profile && incremental.is_some() {
         early_error(