Auto merge of #61886 - Centril:rollup-3p3m2fu, r=Centril

Rollup of 6 pull requests

Successful merges:

 - #61447 (Add some Vec <-> VecDeque documentation)
 - #61704 (Pass LLVM linker flags to librustc_llvm build)
 - #61829 (rustbuild: include llvm-libunwind in dist tarball)
 - #61832 (update miri)
 - #61866 (Remove redundant `clone()`s)
 - #61869 (Cleanup some new active feature gates)

Failed merges:

r? @ghost

Author: bors

src/bootstrap/compile.rs

@@ -775,6 +775,10 @@ pub fn build_codegen_backend(builder: &Builder<'_>,
                     cargo.env("CFG_LLVM_ROOT", s);
                 }
             }
+            // Some LLVM linker flags (-L and -l) may be needed to link librustc_llvm.
+            if let Some(ref s) = builder.config.llvm_ldflags {
+                cargo.env("LLVM_LINKER_FLAGS", s);
+            }
             // Building with a static libstdc++ is only supported on linux right now,
             // not for MSVC or macOS
             if builder.config.llvm_static_stdcpp &&

src/bootstrap/dist.rs

@@ -804,6 +804,7 @@ fn copy_src_dirs(builder: &Builder<'_>, src_dirs: &[&str], exclude_dirs: &[&str]
 
         const LLVM_PROJECTS: &[&str] = &[
             "llvm-project/clang", "llvm-project\\clang",
+            "llvm-project/libunwind", "llvm-project\\libunwind",
             "llvm-project/lld", "llvm-project\\lld",
             "llvm-project/lldb", "llvm-project\\lldb",
             "llvm-project/llvm", "llvm-project\\llvm",

src/liballoc/collections/vec_deque.rs

@@ -2709,6 +2709,11 @@ impl<T: fmt::Debug> fmt::Debug for VecDeque<T> {
 
 #[stable(feature = "vecdeque_vec_conversions", since = "1.10.0")]
 impl<T> From<Vec<T>> for VecDeque<T> {
+    /// Turn a [`Vec<T>`] into a [`VecDeque<T>`].
+    ///
+    /// This avoids reallocating where possible, but the conditions for that are
+    /// strict, and subject to change, and so shouldn't be relied upon unless the
+    /// `Vec<T>` came from `From<VecDeque<T>>` and hasn't been reallocated.
     fn from(mut other: Vec<T>) -> Self {
         unsafe {
             let other_buf = other.as_mut_ptr();
@@ -2735,6 +2740,32 @@ impl<T> From<Vec<T>> for VecDeque<T> {
 
 #[stable(feature = "vecdeque_vec_conversions", since = "1.10.0")]
 impl<T> From<VecDeque<T>> for Vec<T> {
+    /// Turn a [`VecDeque<T>`] into a [`Vec<T>`].
+    ///
+    /// This never needs to re-allocate, but does need to do O(n) data movement if
+    /// the circular buffer doesn't happen to be at the beginning of the allocation.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::collections::VecDeque;
+    ///
+    /// // This one is O(1).
+    /// let deque: VecDeque<_> = (1..5).collect();
+    /// let ptr = deque.as_slices().0.as_ptr();
+    /// let vec = Vec::from(deque);
+    /// assert_eq!(vec, [1, 2, 3, 4]);
+    /// assert_eq!(vec.as_ptr(), ptr);
+    ///
+    /// // This one needs data rearranging.
+    /// let mut deque: VecDeque<_> = (1..5).collect();
+    /// deque.push_front(9);
+    /// deque.push_front(8);
+    /// let ptr = deque.as_slices().1.as_ptr();
+    /// let vec = Vec::from(deque);
+    /// assert_eq!(vec, [8, 9, 1, 2, 3, 4]);
+    /// assert_eq!(vec.as_ptr(), ptr);
+    /// ```
     fn from(other: VecDeque<T>) -> Self {
         unsafe {
             let buf = other.buf.ptr();

src/librustc/infer/opaque_types/mod.rs

@@ -307,7 +307,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
 
             let required_region_bounds = tcx.required_region_bounds(
                 opaque_type,
-                bounds.predicates.clone(),
+                bounds.predicates,
             );
             debug_assert!(!required_region_bounds.is_empty());
 

src/librustc/middle/liveness.rs

@@ -1617,7 +1617,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                     self.ir.tcx.lint_hir_note(
                         lint::builtin::UNUSED_VARIABLES,
                         hir_id,
-                        spans.clone(),
+                        spans,
                         &format!("variable `{}` is assigned to, but never used", name),
                         &format!("consider using `_{}` instead", name),
                     );

src/librustc_borrowck/borrowck/check_loans.rs

@@ -36,7 +36,7 @@ fn owned_ptr_base_path<'a, 'tcx>(loan_path: &'a LoanPath<'tcx>) -> &'a LoanPath<
 
     return match helper(loan_path) {
         Some(new_loan_path) => new_loan_path,
-        None => loan_path.clone()
+        None => loan_path,
     };
 
     fn helper<'a, 'tcx>(loan_path: &'a LoanPath<'tcx>) -> Option<&'a LoanPath<'tcx>> {

src/librustc_codegen_llvm/back/lto.rs

@@ -279,7 +279,7 @@ fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
             }
         }));
         serialized_modules.extend(cached_modules.into_iter().map(|(buffer, wp)| {
-            (buffer, CString::new(wp.cgu_name.clone()).unwrap())
+            (buffer, CString::new(wp.cgu_name).unwrap())
         }));
 
         // For all serialized bitcode files we parse them and link them in as we did

src/librustc_codegen_llvm/context.rs

@@ -459,7 +459,7 @@ impl CodegenCx<'b, 'tcx> {
         };
         let f = self.declare_cfn(name, fn_ty);
         llvm::SetUnnamedAddr(f, false);
-        self.intrinsics.borrow_mut().insert(name, f.clone());
+        self.intrinsics.borrow_mut().insert(name, f);
         f
     }
 

src/librustc_codegen_llvm/debuginfo/metadata.rs

@@ -1609,7 +1609,7 @@ impl<'tcx> VariantInfo<'tcx> {
                 // with every variant, make each variant name be just the value
                 // of the discriminant. The struct name for the variant includes
                 // the actual variant description.
-                format!("{}", variant_index.as_usize()).to_string()
+                format!("{}", variant_index.as_usize())
             }
         }
     }

src/librustc_errors/annotate_snippet_emitter_writer.rs

@@ -194,7 +194,7 @@ impl AnnotateSnippetEmitterWriter {
         let converter = DiagnosticConverter {
             source_map: self.source_map.clone(),
             level: level.clone(),
-            message: message.clone(),
+            message,
             code: code.clone(),
             msp: msp.clone(),
             children,