Auto merge of #61075 - Centril:rollup-1ugmcqu, r=Centril

Rollup of 7 pull requests

Successful merges:

 - #60981 (Bump compiler-builtins to 0.1.15)
 - #61014 (Make -Zemit-artifact-notifications also emit the artifact type)
 - #61043 (Disable LLVM/debug assertions in gnu-full-bootstrap)
 - #61046 (Fix ICE with inconsistent macro matchers)
 - #61055 (Solaris CI: Build with dilos2 stable)
 - #61057 (Revert "Add implementations of last in terms of next_back on a bunch of DoubleEndedIterators.")
 - #61073 (librustc_errors: Remove unused annotation style `OldSchoolNoteText`)

Failed merges:

r? @ghost

35 files changed, 129 insertions, 206 deletions

diff --git a/Cargo.lock b/Cargo.lock
index db9f0069ced..b651faac902 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -25,7 +25,7 @@ dependencies = [
 name = "alloc"
 version = "0.0.0"
 dependencies = [
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_xorshift 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -123,7 +123,7 @@ version = "0.1.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
@@ -462,7 +462,7 @@ dependencies = [
 
 [[package]]
 name = "compiler_builtins"
-version = "0.1.14"
+version = "0.1.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -744,7 +744,7 @@ name = "dlmalloc"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
@@ -910,7 +910,7 @@ name = "fortanix-sgx-abi"
 version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -1071,7 +1071,7 @@ name = "hashbrown"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-alloc 1.0.0",
  "rustc-std-workspace-core 1.0.0",
 ]
@@ -1772,7 +1772,7 @@ dependencies = [
 name = "panic_abort"
 version = "0.0.0"
 dependencies = [
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1782,7 +1782,7 @@ name = "panic_unwind"
 version = "0.0.0"
 dependencies = [
  "alloc 0.0.0",
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "unwind 0.0.0",
@@ -1967,7 +1967,7 @@ name = "profiler_builtins"
 version = "0.0.0"
 dependencies = [
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2492,7 +2492,7 @@ name = "rustc-demangle"
 version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -2620,7 +2620,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.38 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2850,7 +2850,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.38 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2912,7 +2912,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.38 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -3029,7 +3029,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.38 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -3298,7 +3298,7 @@ dependencies = [
  "alloc 0.0.0",
  "backtrace-sys 0.1.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "dlmalloc 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fortanix-sgx-abi 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3889,7 +3889,7 @@ name = "unwind"
 version = "0.0.0"
 dependencies = [
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -4087,7 +4087,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum colored 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b0aa3473e85a3161b59845d6096b289bb577874cafeaf75ea1b1beaa6572c7fc"
 "checksum commoncrypto 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d056a8586ba25a1e4d61cb090900e495952c7886786fc55f909ab2f819b69007"
 "checksum commoncrypto-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1fed34f46747aa73dfaa578069fd8279d2818ade2b55f38f22a9401c7f4083e2"
-"checksum compiler_builtins 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)" = "e3f235c329e5cb9fa3d2ca2cc36256ba9a7f23fa76e0f4db6f68c23b73b2ac69"
+"checksum compiler_builtins 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)" = "e899b947d7e71c3d35c0b6194d64025b84946640510e215090c815b20828964e"
 "checksum compiletest_rs 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)" = "f40ecc9332b68270998995c00f8051ee856121764a0d3230e64c9efd059d27b6"
 "checksum constant_time_eq 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8ff012e225ce166d4422e0e78419d901719760f62ae2b7969ca6b564d1b54a9e"
 "checksum core-foundation 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4e2640d6d0bf22e82bed1b73c6aef8d5dd31e5abe6666c57e6d45e2649f4f887"
diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index e1cdd226fd6..2da5e1c5902 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -161,7 +161,33 @@ pub fn std_cargo(builder: &Builder<'_>,
         cargo.env("MACOSX_DEPLOYMENT_TARGET", target);
     }
 
+    // Determine if we're going to compile in optimized C intrinsics to
+    // the `compiler-builtins` crate. These intrinsics live in LLVM's
+    // `compiler-rt` repository, but our `src/llvm-project` submodule isn't
+    // always checked out, so we need to conditionally look for this. (e.g. if
+    // an external LLVM is used we skip the LLVM submodule checkout).
+    //
+    // Note that this shouldn't affect the correctness of `compiler-builtins`,
+    // but only its speed. Some intrinsics in C haven't been translated to Rust
+    // yet but that's pretty rare. Other intrinsics have optimized
+    // implementations in C which have only had slower versions ported to Rust,
+    // so we favor the C version where we can, but it's not critical.
+    //
+    // If `compiler-rt` is available ensure that the `c` feature of the
+    // `compiler-builtins` crate is enabled and it's configured to learn where
+    // `compiler-rt` is located.
+    let compiler_builtins_root = builder.src.join("src/llvm-project/compiler-rt");
+    let compiler_builtins_c_feature = if compiler_builtins_root.exists() {
+        cargo.env("RUST_COMPILER_RT_ROOT", &compiler_builtins_root);
+        " compiler-builtins-c".to_string()
+    } else {
+        String::new()
+    };
+
     if builder.no_std(target) == Some(true) {
+        let mut features = "compiler-builtins-mem".to_string();
+        features.push_str(&compiler_builtins_c_feature);
+
         // for no-std targets we only compile a few no_std crates
         cargo
             .args(&["-p", "alloc"])
@@ -170,7 +196,8 @@ pub fn std_cargo(builder: &Builder<'_>,
             .arg("--features")
             .arg("compiler-builtins-mem compiler-builtins-c");
     } else {
-        let features = builder.std_features();
+        let mut features = builder.std_features();
+        features.push_str(&compiler_builtins_c_feature);
 
         if compiler.stage != 0 && builder.config.sanitizers {
             // This variable is used by the sanitizer runtime crates, e.g.
diff --git a/src/build_helper/lib.rs b/src/build_helper/lib.rs
index 60911d91789..8b00c1d81b0 100644
--- a/src/build_helper/lib.rs
+++ b/src/build_helper/lib.rs
@@ -288,9 +288,9 @@ pub fn sanitizer_lib_boilerplate(sanitizer_name: &str)
     } else {
         format!("static={}", link_name)
     };
-    // The source for `compiler-rt` comes from the `compiler-builtins` crate, so
-    // load our env var set by cargo to find the source code.
-    let dir = env::var_os("DEP_COMPILER_RT_COMPILER_RT").unwrap();
+    // This env var is provided by rustbuild to tell us where `compiler-rt`
+    // lives.
+    let dir = env::var_os("RUST_COMPILER_RT_ROOT").unwrap();
     let lib = native_lib_boilerplate(
         dir.as_ref(),
         sanitizer_name,
diff --git a/src/ci/docker/dist-various-2/Dockerfile b/src/ci/docker/dist-various-2/Dockerfile
index 869ee9883c1..e7d6f201b44 100644
--- a/src/ci/docker/dist-various-2/Dockerfile
+++ b/src/ci/docker/dist-various-2/Dockerfile
@@ -24,7 +24,7 @@ RUN apt-get update && apt-get build-dep -y clang llvm && apt-get install -y --no
   gpg-agent
 
 RUN apt-key adv --batch --yes --keyserver keyserver.ubuntu.com --recv-keys 74DA7924C5513486
-RUN add-apt-repository -y 'deb http://apt.dilos.org/dilos dilos2-testing main'
+RUN add-apt-repository -y 'deb http://apt.dilos.org/dilos dilos2 main'
 
 WORKDIR /tmp
 COPY dist-various-2/shared.sh /tmp/
diff --git a/src/ci/docker/x86_64-gnu-full-bootstrap/Dockerfile b/src/ci/docker/x86_64-gnu-full-bootstrap/Dockerfile
index 70390c2ac1d..a157fee16cf 100644
--- a/src/ci/docker/x86_64-gnu-full-bootstrap/Dockerfile
+++ b/src/ci/docker/x86_64-gnu-full-bootstrap/Dockerfile
@@ -20,3 +20,9 @@ ENV RUST_CONFIGURE_ARGS \
       --build=x86_64-unknown-linux-gnu \
       --enable-full-bootstrap
 ENV SCRIPT python2.7 ../x.py build
+
+# In general this just slows down the build and we're just a smoke test that
+# a full bootstrap works in general, so there's not much need to take this
+# penalty in build times.
+ENV NO_LLVM_ASSERTIONS 1
+ENV NO_DEBUG_ASSERTIONS 1
diff --git a/src/liballoc/collections/binary_heap.rs b/src/liballoc/collections/binary_heap.rs
index c5a0b6e877b..c898f064fd0 100644
--- a/src/liballoc/collections/binary_heap.rs
+++ b/src/liballoc/collections/binary_heap.rs
@@ -1035,11 +1035,6 @@ impl<'a, T> Iterator for Iter<'a, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<&'a T> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1095,11 +1090,6 @@ impl<T> Iterator for IntoIter<T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<T> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1146,11 +1136,6 @@ impl<T> Iterator for Drain<'_, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<T> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
diff --git a/src/liballoc/collections/btree/map.rs b/src/liballoc/collections/btree/map.rs
index 414abb00ef1..6b079fc87cc 100644
--- a/src/liballoc/collections/btree/map.rs
+++ b/src/liballoc/collections/btree/map.rs
@@ -1193,11 +1193,6 @@ impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.length, Some(self.length))
     }
-
-    #[inline]
-    fn last(mut self) -> Option<(&'a K, &'a V)> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
@@ -1258,11 +1253,6 @@ impl<'a, K: 'a, V: 'a> Iterator for IterMut<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.length, Some(self.length))
     }
-
-    #[inline]
-    fn last(mut self) -> Option<(&'a K, &'a mut V)> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1369,11 +1359,6 @@ impl<K, V> Iterator for IntoIter<K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.length, Some(self.length))
     }
-
-    #[inline]
-    fn last(mut self) -> Option<(K, V)> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1436,11 +1421,6 @@ impl<'a, K, V> Iterator for Keys<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<&'a K> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1478,11 +1458,6 @@ impl<'a, K, V> Iterator for Values<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<&'a V> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1520,11 +1495,6 @@ impl<'a, K, V> Iterator for Range<'a, K, V> {
             unsafe { Some(self.next_unchecked()) }
         }
     }
-
-    #[inline]
-    fn last(mut self) -> Option<(&'a K, &'a V)> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "map_values_mut", since = "1.10.0")]
@@ -1538,11 +1508,6 @@ impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<&'a mut V> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "map_values_mut", since = "1.10.0")]
@@ -1661,11 +1626,6 @@ impl<'a, K, V> Iterator for RangeMut<'a, K, V> {
             unsafe { Some(self.next_unchecked()) }
         }
     }
-
-    #[inline]
-    fn last(mut self) -> Option<(&'a K, &'a mut V)> {
-        self.next_back()
-    }
 }
 
 impl<'a, K, V> RangeMut<'a, K, V> {
diff --git a/src/liballoc/collections/btree/set.rs b/src/liballoc/collections/btree/set.rs
index 6f2467dfd6b..16a96ca19b8 100644
--- a/src/liballoc/collections/btree/set.rs
+++ b/src/liballoc/collections/btree/set.rs
@@ -1019,11 +1019,6 @@ impl<'a, T> Iterator for Iter<'a, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<&'a T> {
-        self.next_back()
-    }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
@@ -1049,11 +1044,6 @@ impl<T> Iterator for IntoIter<T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<T> {
-        self.next_back()
-    }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> DoubleEndedIterator for IntoIter<T> {
@@ -1083,11 +1073,6 @@ impl<'a, T> Iterator for Range<'a, T> {
     fn next(&mut self) -> Option<&'a T> {
         self.iter.next().map(|(k, _)| k)
     }
-
-    #[inline]
-    fn last(mut self) -> Option<&'a T> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "btree_range", since = "1.17.0")]
diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index e74d37c1c2b..7f7722548f5 100644
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -2385,10 +2385,6 @@ impl Iterator for Drain<'_> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
-    #[inline]
-    fn last(mut self) -> Option<char> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index c0cdffe596b..073d3ab5937 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -2395,11 +2395,6 @@ impl<T> Iterator for IntoIter<T> {
     fn count(self) -> usize {
         self.len()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<T> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -2519,11 +2514,6 @@ impl<T> Iterator for Drain<'_, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<T> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
@@ -2593,10 +2583,6 @@ impl<I: Iterator> Iterator for Splice<'_, I> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.drain.size_hint()
     }
-
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "vec_splice", since = "1.21.0")]
diff --git a/src/libcore/ascii.rs b/src/libcore/ascii.rs
index ddee02ea232..c0ab364380f 100644
--- a/src/libcore/ascii.rs
+++ b/src/libcore/ascii.rs
@@ -117,8 +117,6 @@ impl Iterator for EscapeDefault {
     type Item = u8;
     fn next(&mut self) -> Option<u8> { self.range.next().map(|i| self.data[i]) }
     fn size_hint(&self) -> (usize, Option<usize>) { self.range.size_hint() }
-    #[inline]
-    fn last(mut self) -> Option<u8> { self.next_back() }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl DoubleEndedIterator for EscapeDefault {
diff --git a/src/libcore/iter/adapters/mod.rs b/src/libcore/iter/adapters/mod.rs
index 64e588f65b4..518442efe74 100644
--- a/src/libcore/iter/adapters/mod.rs
+++ b/src/libcore/iter/adapters/mod.rs
@@ -73,11 +73,6 @@ impl<I> Iterator for Rev<I> where I: DoubleEndedIterator {
     {
         self.iter.position(predicate)
     }
-
-    #[inline]
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libcore/slice/mod.rs b/src/libcore/slice/mod.rs
index d06d107d32a..50d2ba0d3ef 100644
--- a/src/libcore/slice/mod.rs
+++ b/src/libcore/slice/mod.rs
@@ -3547,11 +3547,6 @@ impl<'a, T, P> Iterator for Split<'a, T, P> where P: FnMut(&T) -> bool {
             (1, Some(self.v.len() + 1))
         }
     }
-
-    #[inline]
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -3650,11 +3645,6 @@ impl<'a, T, P> Iterator for SplitMut<'a, T, P> where P: FnMut(&T) -> bool {
             (1, Some(self.v.len() + 1))
         }
     }
-
-    #[inline]
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -3720,11 +3710,6 @@ impl<'a, T, P> Iterator for RSplit<'a, T, P> where P: FnMut(&T) -> bool {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "slice_rsplit", since = "1.27.0")]
@@ -3789,11 +3774,6 @@ impl<'a, T, P> Iterator for RSplitMut<'a, T, P> where P: FnMut(&T) -> bool {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "slice_rsplit", since = "1.27.0")]
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index 0e8a2da3c11..ef4bd83cbc5 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -1333,11 +1333,6 @@ impl<'a> Iterator for Lines<'a> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.0.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1384,11 +1379,6 @@ impl<'a> Iterator for LinesAny<'a> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.0.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -4231,11 +4221,6 @@ impl<'a> Iterator for SplitWhitespace<'a> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "split_whitespace", since = "1.1.0")]
@@ -4262,11 +4247,6 @@ impl<'a> Iterator for SplitAsciiWhitespace<'a> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
-
-    #[inline]
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
diff --git a/src/libprofiler_builtins/build.rs b/src/libprofiler_builtins/build.rs
index 331edb73d6d..491986480de 100644
--- a/src/libprofiler_builtins/build.rs
+++ b/src/libprofiler_builtins/build.rs
@@ -57,9 +57,7 @@ fn main() {
         cfg.define("COMPILER_RT_HAS_ATOMICS", Some("1"));
     }
 
-    // The source for `compiler-rt` comes from the `compiler-builtins` crate, so
-    // load our env var set by cargo to find the source code.
-    let root = env::var_os("DEP_COMPILER_RT_COMPILER_RT").unwrap();
+    let root = env::var_os("RUST_COMPILER_RT_ROOT").unwrap();
     let root = Path::new(&root);
 
     for src in profile_sources {
diff --git a/src/librustc_codegen_ssa/back/link.rs b/src/librustc_codegen_ssa/back/link.rs
index d5a56f6a09e..c1ec2071789 100644
--- a/src/librustc_codegen_ssa/back/link.rs
+++ b/src/librustc_codegen_ssa/back/link.rs
@@ -96,7 +96,7 @@ pub fn link_binary<'a, B: ArchiveBuilder<'a>>(sess: &'a Session,
                 }
             }
             if sess.opts.debugging_opts.emit_artifact_notifications {
-                sess.parse_sess.span_diagnostic.emit_artifact_notification(&out_filename);
+                sess.parse_sess.span_diagnostic.emit_artifact_notification(&out_filename, "link");
             }
         }
 
diff --git a/src/librustc_errors/emitter.rs b/src/librustc_errors/emitter.rs
index 59cbd65f05c..890d2c5ce0b 100644
--- a/src/librustc_errors/emitter.rs
+++ b/src/librustc_errors/emitter.rs
@@ -56,7 +56,7 @@ pub trait Emitter {
     /// Emit a notification that an artifact has been output.
     /// This is currently only supported for the JSON format,
     /// other formats can, and will, simply ignore it.
-    fn emit_artifact_notification(&mut self, _path: &Path) {}
+    fn emit_artifact_notification(&mut self, _path: &Path, _artifact_type: &str) {}
 
     /// Checks if should show explanations about "rustc --explain"
     fn should_show_explain(&self) -> bool {
@@ -1645,7 +1645,7 @@ impl<'a> WritableDst<'a> {
                 }
             }
             Style::Quotation => {}
-            Style::OldSchoolNoteText | Style::MainHeaderMsg => {
+            Style::MainHeaderMsg => {
                 spec.set_bold(true);
                 if cfg!(windows) {
                     spec.set_intense(true)
diff --git a/src/librustc_errors/lib.rs b/src/librustc_errors/lib.rs
index 3aa87fad071..2dcf7be2aa8 100644
--- a/src/librustc_errors/lib.rs
+++ b/src/librustc_errors/lib.rs
@@ -769,8 +769,8 @@ impl Handler {
         }
     }
 
-    pub fn emit_artifact_notification(&self, path: &Path) {
-        self.emitter.borrow_mut().emit_artifact_notification(path);
+    pub fn emit_artifact_notification(&self, path: &Path, artifact_type: &str) {
+        self.emitter.borrow_mut().emit_artifact_notification(path, artifact_type);
     }
 }
 
diff --git a/src/librustc_errors/snippet.rs b/src/librustc_errors/snippet.rs
index a0af604026d..47ba22d3d25 100644
--- a/src/librustc_errors/snippet.rs
+++ b/src/librustc_errors/snippet.rs
@@ -188,7 +188,6 @@ pub enum Style {
     UnderlineSecondary,
     LabelPrimary,
     LabelSecondary,
-    OldSchoolNoteText,
     NoStyle,
     Level(Level),
     Highlight,
diff --git a/src/librustc_interface/passes.rs b/src/librustc_interface/passes.rs
index 04041f88344..4a96864dc9d 100644
--- a/src/librustc_interface/passes.rs
+++ b/src/librustc_interface/passes.rs
@@ -1050,7 +1050,8 @@ fn encode_and_write_metadata<'tcx>(
             tcx.sess.fatal(&format!("failed to write {}: {}", out_filename.display(), e));
         }
         if tcx.sess.opts.debugging_opts.emit_artifact_notifications {
-            tcx.sess.parse_sess.span_diagnostic.emit_artifact_notification(&out_filename);
+            tcx.sess.parse_sess.span_diagnostic
+                .emit_artifact_notification(&out_filename, "metadata");
         }
     }
 
diff --git a/src/libstd/Cargo.toml b/src/libstd/Cargo.toml
index 55e8b39974e..c4c1170e539 100644
--- a/src/libstd/Cargo.toml
+++ b/src/libstd/Cargo.toml
@@ -19,7 +19,7 @@ panic_unwind = { path = "../libpanic_unwind", optional = true }
 panic_abort = { path = "../libpanic_abort" }
 core = { path = "../libcore" }
 libc = { version = "0.2.51", default-features = false, features = ['rustc-dep-of-std'] }
-compiler_builtins = { version = "0.1.14" }
+compiler_builtins = { version = "0.1.15" }
 profiler_builtins = { path = "../libprofiler_builtins", optional = true }
 unwind = { path = "../libunwind" }
 hashbrown = { version = "0.3.0", features = ['rustc-dep-of-std'] }
@@ -49,12 +49,12 @@ fortanix-sgx-abi = { version = "0.3.2", features = ['rustc-dep-of-std'] }
 cc = "1.0"
 
 [features]
-default = ["compiler_builtins_c", "std_detect_file_io", "std_detect_dlsym_getauxval"]
+default = ["std_detect_file_io", "std_detect_dlsym_getauxval"]
 
 backtrace = ["backtrace-sys"]
 panic-unwind = ["panic_unwind"]
 profiler = ["profiler_builtins"]
-compiler_builtins_c = ["alloc/compiler-builtins-c"]
+compiler-builtins-c = ["alloc/compiler-builtins-c"]
 llvm-libunwind = ["unwind/llvm-libunwind"]
 
 # Make panics and failed asserts immediately abort without formatting any message
diff --git a/src/libstd/env.rs b/src/libstd/env.rs
index 260624a8bd8..9058ea93d6d 100644
--- a/src/libstd/env.rs
+++ b/src/libstd/env.rs
@@ -746,10 +746,6 @@ impl Iterator for Args {
         self.inner.next().map(|s| s.into_string().unwrap())
     }
     fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
-    #[inline]
-    fn last(mut self) -> Option<String> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "env", since = "1.0.0")]
@@ -785,8 +781,6 @@ impl Iterator for ArgsOs {
     type Item = OsString;
     fn next(&mut self) -> Option<OsString> { self.inner.next() }
     fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
-    #[inline]
-    fn last(mut self) -> Option<OsString> { self.next_back() }
 }
 
 #[stable(feature = "env", since = "1.0.0")]
diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index 59f9e439add..126bc3754da 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -888,11 +888,6 @@ impl<'a> Iterator for Iter<'a> {
     fn next(&mut self) -> Option<&'a OsStr> {
         self.inner.next().map(Component::as_os_str)
     }
-
-    #[inline]
-    fn last(mut self) -> Option<&'a OsStr> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -956,11 +951,6 @@ impl<'a> Iterator for Components<'a> {
         }
         None
     }
-
-    #[inline]
-    fn last(mut self) -> Option<Self::Item> {
-        self.next_back()
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libstd/sys/unix/args.rs b/src/libstd/sys/unix/args.rs
index 6ba947d4598..3b4de56f2c9 100644
--- a/src/libstd/sys/unix/args.rs
+++ b/src/libstd/sys/unix/args.rs
@@ -35,8 +35,6 @@ impl Iterator for Args {
     type Item = OsString;
     fn next(&mut self) -> Option<OsString> { self.iter.next() }
     fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() }
-    #[inline]
-    fn last(mut self) -> Option<OsString> { self.next_back() }
 }
 
 impl ExactSizeIterator for Args {
diff --git a/src/libstd/sys/wasm/args.rs b/src/libstd/sys/wasm/args.rs
index 6766099c1ec..b3c77b86995 100644
--- a/src/libstd/sys/wasm/args.rs
+++ b/src/libstd/sys/wasm/args.rs
@@ -37,10 +37,6 @@ impl Iterator for Args {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
-    #[inline]
-    fn last(mut self) -> Option<OsString> {
-        self.next_back()
-    }
 }
 
 impl ExactSizeIterator for Args {
diff --git a/src/libstd/sys/windows/args.rs b/src/libstd/sys/windows/args.rs
index 744d7ec59d3..b04bb484eed 100644
--- a/src/libstd/sys/windows/args.rs
+++ b/src/libstd/sys/windows/args.rs
@@ -181,8 +181,6 @@ impl Iterator for Args {
     type Item = OsString;
     fn next(&mut self) -> Option<OsString> { self.parsed_args_list.next() }
     fn size_hint(&self) -> (usize, Option<usize>) { self.parsed_args_list.size_hint() }
-    #[inline]
-    fn last(mut self) -> Option<OsString> { self.next_back() }
 }
 
 impl DoubleEndedIterator for Args {
diff --git a/src/libsyntax/ext/tt/transcribe.rs b/src/libsyntax/ext/tt/transcribe.rs
index e3586c1854c..e6b49e61937 100644
--- a/src/libsyntax/ext/tt/transcribe.rs
+++ b/src/libsyntax/ext/tt/transcribe.rs
@@ -170,9 +170,11 @@ pub fn transcribe(
                     }
 
                     LockstepIterSize::Contradiction(ref msg) => {
-                        // This should never happen because the macro parser should generate
-                        // properly-sized matches for all meta-vars.
-                        cx.span_bug(seq.span(), &msg[..]);
+                        // FIXME: this really ought to be caught at macro definition time... It
+                        // happens when two meta-variables are used in the same repetition in a
+                        // sequence, but they come from different sequence matchers and repeat
+                        // different amounts.
+                        cx.span_fatal(seq.span(), &msg[..]);
                     }
 
                     LockstepIterSize::Constraint(len, _) => {
@@ -187,9 +189,10 @@ pub fn transcribe(
                         // Is the repetition empty?
                         if len == 0 {
                             if seq.op == quoted::KleeneOp::OneOrMore {
-                                // This should be impossible because the macro parser would not
-                                // match the given macro arm.
-                                cx.span_bug(sp.entire(), "this must repeat at least once");
+                                // FIXME: this really ought to be caught at macro definition
+                                // time... It happens when the Kleene operator in the matcher and
+                                // the body for the same meta-variable do not match.
+                                cx.span_fatal(sp.entire(), "this must repeat at least once");
                             }
                         } else {
                             // 0 is the initial counter (we have done 0 repretitions so far). `len`
@@ -327,8 +330,7 @@ impl LockstepIterSize {
                 LockstepIterSize::Constraint(r_len, _) if l_len == r_len => self,
                 LockstepIterSize::Constraint(r_len, r_id) => {
                     let msg = format!(
-                        "inconsistent lockstep iteration: \
-                         '{}' has {} items, but '{}' has {}",
+                        "meta-variable `{}` repeats {} times, but `{}` repeats {} times",
                         l_id, l_len, r_id, r_len
                     );
                     LockstepIterSize::Contradiction(msg)
diff --git a/src/libsyntax/json.rs b/src/libsyntax/json.rs
index 2dd2ecb7493..767ab74355e 100644
--- a/src/libsyntax/json.rs
+++ b/src/libsyntax/json.rs
@@ -92,8 +92,8 @@ impl Emitter for JsonEmitter {
         }
     }
 
-    fn emit_artifact_notification(&mut self, path: &Path) {
-        let data = ArtifactNotification { artifact: path };
+    fn emit_artifact_notification(&mut self, path: &Path, artifact_type: &str) {
+        let data = ArtifactNotification { artifact: path, emit: artifact_type };
         let result = if self.pretty {
             writeln!(&mut self.dst, "{}", as_pretty_json(&data))
         } else {
@@ -185,6 +185,8 @@ struct DiagnosticCode {
 struct ArtifactNotification<'a> {
     /// The path of the artifact.
     artifact: &'a Path,
+    /// What kind of artifact we're emitting.
+    emit: &'a str,
 }
 
 impl Diagnostic {
diff --git a/src/llvm-project b/src/llvm-project
-Subproject 2c5656ae593851d0b2336a727cc14b77a06b8ac
+Subproject 4efebe31651d5520bcba968878dbb8a4971d204
diff --git a/src/test/ui/emit-artifact-notifications.nll.stderr b/src/test/ui/emit-artifact-notifications.nll.stderr
index 347d9aeac23..5547631a4b0 100644
--- a/src/test/ui/emit-artifact-notifications.nll.stderr
+++ b/src/test/ui/emit-artifact-notifications.nll.stderr
@@ -1 +1 @@
-{"artifact":"$TEST_BUILD_DIR/emit-artifact-notifications.nll/libemit_artifact_notifications.rmeta"}
+{"artifact":"$TEST_BUILD_DIR/emit-artifact-notifications.nll/libemit_artifact_notifications.rmeta","emit":"metadata"}
diff --git a/src/test/ui/emit-artifact-notifications.stderr b/src/test/ui/emit-artifact-notifications.stderr
index 56c977181ff..260d41b8f15 100644
--- a/src/test/ui/emit-artifact-notifications.stderr
+++ b/src/test/ui/emit-artifact-notifications.stderr
@@ -1 +1 @@
-{"artifact":"$TEST_BUILD_DIR/emit-artifact-notifications/libemit_artifact_notifications.rmeta"}
+{"artifact":"$TEST_BUILD_DIR/emit-artifact-notifications/libemit_artifact_notifications.rmeta","emit":"metadata"}
diff --git a/src/test/ui/macros/issue-61033-1.rs b/src/test/ui/macros/issue-61033-1.rs
new file mode 100644
index 00000000000..8f85dec017f
--- /dev/null
+++ b/src/test/ui/macros/issue-61033-1.rs
@@ -0,0 +1,9 @@
+// Regression test for issue #61033.
+
+macro_rules! test1 {
+    ($x:ident, $($tt:tt)*) => { $($tt)+ } //~ERROR this must repeat at least once
+}
+
+fn main() {
+    test1!(x,);
+}
diff --git a/src/test/ui/macros/issue-61033-1.stderr b/src/test/ui/macros/issue-61033-1.stderr
new file mode 100644
index 00000000000..f3c68f4928d
--- /dev/null
+++ b/src/test/ui/macros/issue-61033-1.stderr
@@ -0,0 +1,8 @@
+error: this must repeat at least once
+  --> $DIR/issue-61033-1.rs:4:34
+   |
+LL |     ($x:ident, $($tt:tt)*) => { $($tt)+ }
+   |                                  ^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/macros/issue-61033-2.rs b/src/test/ui/macros/issue-61033-2.rs
new file mode 100644
index 00000000000..0799be10b96
--- /dev/null
+++ b/src/test/ui/macros/issue-61033-2.rs
@@ -0,0 +1,19 @@
+// Regression test for issue #61033.
+
+macro_rules! test2 {
+    (
+        $(* $id1:ident)*
+        $(+ $id2:ident)*
+    ) => {
+        $( //~ERROR meta-variable `id1` repeats 2 times
+            $id1 + $id2 // $id1 and $id2 may repeat different numbers of times
+        )*
+    }
+}
+
+fn main() {
+    test2! {
+        * a * b
+        + a + b + c
+    }
+}
diff --git a/src/test/ui/macros/issue-61033-2.stderr b/src/test/ui/macros/issue-61033-2.stderr
new file mode 100644
index 00000000000..bf502919cf7
--- /dev/null
+++ b/src/test/ui/macros/issue-61033-2.stderr
@@ -0,0 +1,11 @@
+error: meta-variable `id1` repeats 2 times, but `id2` repeats 3 times
+  --> $DIR/issue-61033-2.rs:8:10
+   |
+LL |           $(
+   |  __________^
+LL | |             $id1 + $id2 // $id1 and $id2 may repeat different numbers of times
+LL | |         )*
+   | |_________^
+
+error: aborting due to previous error
+