Auto merge of #77917 - JohnTitor:rollup-e47h2qt, r=JohnTitor

Rollup of 14 pull requests

Successful merges:

 - #77239 (Enable building Cargo for aarch64-apple-darwin)
 - #77569 (BTreeMap: type-specific variants of node_as_mut and cast_unchecked)
 - #77719 (Remove unnecessary rustc_const_stable attributes.)
 - #77722 (Remove unsafety from sys/unsupported and add deny(unsafe_op_in_unsafe_fn).)
 - #77725 (Add regression issue template)
 - #77776 ( Give an error when running `x.py test --stage 0 src/test/ui`)
 - #77786 (Mention rustdoc in `x.py setup`)
 - #77825 (`min_const_generics` diagnostics improvements)
 - #77868 (Include `llvm-dis`, `llc` and `opt` in `llvm-tools-preview` component)
 - #77884 (Use Option::unwrap_or instead of open-coding it)
 - #77886 (Replace trivial bool matches with the `matches!` macro)
 - #77892 (Replace absolute paths with relative ones)
 - #77895 (Include aarch64-apple-darwin in the dist manifests)
 - #77909 (bootstrap: set correct path for the build-manifest binary)

Failed merges:

 - #77902 (Include aarch64-pc-windows-msvc in the dist manifests)

r? `@ghost`

.github/ISSUE_TEMPLATE/regression.md

@@ -0,0 +1,68 @@
+---
+name: Regression
+about: Report something that unexpectedly changed between Rust versions.
+labels: C-bug regression-untriaged
+---
+<!--
+Thank you for filing a regression report! 🐛 A regression is something that changed between versions of Rust but was not supposed to.
+
+Please provide a short summary of the regression, along with any information you feel is relevant to replicate it.
+-->
+
+### Code
+
+I tried this code:
+
+```rust
+<code>
+```
+
+I expected to see this happen: *explanation*
+
+Instead, this happened: *explanation*
+
+### Version it worked on
+
+<!--
+Provide the most recent version this worked on, for example:
+
+It most recently worked on: Rust 1.47
+-->
+
+It most recently worked on: <!-- version -->
+
+### Version with regression
+
+<!--
+Provide the version you are using that has the regression.
+-->
+
+`rustc --version --verbose`:
+```
+<version>
+```
+
+<!--
+Did the compiler crash? If so, please provide a backtrace.
+-->
+
+### Backtrace
+<!--
+Include a backtrace in the code block by setting `RUST_BACKTRACE=1` in your
+environment. E.g. `RUST_BACKTRACE=1 cargo build`.
+-->
+<details><summary>Backtrace</summary>
+<p>
+
+```
+<backtrace>
+```
+
+</p>
+</details>
+
+<!--
+If you know when this regression occurred, please add a line like below, replacing `{channel}` with one of stable, beta, or nightly.
+
+@rustbot modify labels: +regression-from-stable-to-{channel} -regression-untriaged
+-->

.github/workflows/ci.yml

@@ -306,7 +306,7 @@ jobs:
           - name: dist-aarch64-apple
             env:
               SCRIPT: "./x.py dist --stage 2"
-              RUST_CONFIGURE_ARGS: "--build=x86_64-apple-darwin --host=aarch64-apple-darwin --target=aarch64-apple-darwin --enable-sanitizers --enable-profiler --set rust.jemalloc --set llvm.ninja=false --tools=rls,clippy,rustfmt,analysis,src"
+              RUST_CONFIGURE_ARGS: "--build=x86_64-apple-darwin --host=aarch64-apple-darwin --target=aarch64-apple-darwin --enable-full-tools --enable-sanitizers --enable-profiler --set rust.jemalloc --set llvm.ninja=false"
               RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
               SELECT_XCODE: /Applications/Xcode_12_beta.app
               USE_XCODE_CLANG: 1
@@ -314,6 +314,8 @@ jobs:
               MACOSX_STD_DEPLOYMENT_TARGET: 11.0
               NO_LLVM_ASSERTIONS: 1
               NO_DEBUG_ASSERTIONS: 1
+              DIST_REQUIRE_ALL_TOOLS: 1
+              JEMALLOC_SYS_WITH_LG_PAGE: 14
             os: macos-latest
           - name: x86_64-msvc-1
             env:

Cargo.lock

@@ -2192,9 +2192,9 @@ checksum = "77af24da69f9d9341038eba93a073b1fdaaa1b788221b00a69bce9e762cb32de"
 
 [[package]]
 name = "openssl-src"
-version = "111.10.2+1.1.1g"
+version = "111.12.0+1.1.1h"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a287fdb22e32b5b60624d4a5a7a02dbe82777f730ec0dbc42a0554326fef5a70"
+checksum = "858a4132194f8570a7ee9eb8629e85b23cbc4565f2d4a162e87556e5956abf61"
 dependencies = [
  "cc",
 ]

compiler/rustc_ast_pretty/src/pp.rs

@@ -170,17 +170,11 @@ pub enum Token {
 
 impl Token {
     crate fn is_eof(&self) -> bool {
-        match *self {
+        matches!(self, Token::Eof)
-            Token::Eof => true,
-            _ => false,
-        }
     }
 
     pub fn is_hardbreak_tok(&self) -> bool {
-        match *self {
+        matches!(self, Token::Break(BreakToken { offset: 0, blank_space: SIZE_INFINITY }))
-            Token::Break(BreakToken { offset: 0, blank_space: bs }) if bs == SIZE_INFINITY => true,
-            _ => false,
-        }
     }
 }
 
@@ -491,12 +485,9 @@ impl Printer {
     }
 
     fn get_top(&mut self) -> PrintStackElem {
-        match self.print_stack.last() {
+        *self.print_stack.last().unwrap_or({
-            Some(el) => *el,
+            &PrintStackElem { offset: 0, pbreak: PrintStackBreak::Broken(Breaks::Inconsistent) }
-            None => {
+        })
-                PrintStackElem { offset: 0, pbreak: PrintStackBreak::Broken(Breaks::Inconsistent) }
-            }
-        }
     }
 
     fn print_begin(&mut self, b: BeginToken, l: isize) {

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -122,7 +122,7 @@ unsafe fn configure_llvm(sess: &Session) {
 
     llvm::LLVMInitializePasses();
 
-    ::rustc_llvm::initialize_available_targets();
+    rustc_llvm::initialize_available_targets();
 
     llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int, llvm_args.as_ptr());
 }

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -1175,7 +1175,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
     // necessary. There's already optimizations in place to avoid sending work
     // back to the coordinator if LTO isn't requested.
     return thread::spawn(move || {
-        let max_workers = ::num_cpus::get();
+        let max_workers = num_cpus::get();
         let mut worker_id_counter = 0;
         let mut free_worker_ids = Vec::new();
         let mut get_worker_id = |free_worker_ids: &mut Vec<usize>| {

compiler/rustc_codegen_ssa/src/base.rs

@@ -695,7 +695,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
         total_codegen_time.into_inner(),
     );
 
-    ::rustc_incremental::assert_module_sources::assert_module_sources(tcx);
+    rustc_incremental::assert_module_sources::assert_module_sources(tcx);
 
     symbol_names_test::report_symbol_names(tcx);
 
@@ -754,8 +754,8 @@ impl<B: ExtraBackendMethods> Drop for AbortCodegenOnDrop<B> {
 }
 
 fn finalize_tcx(tcx: TyCtxt<'_>) {
-    tcx.sess.time("assert_dep_graph", || ::rustc_incremental::assert_dep_graph(tcx));
+    tcx.sess.time("assert_dep_graph", || rustc_incremental::assert_dep_graph(tcx));
-    tcx.sess.time("serialize_dep_graph", || ::rustc_incremental::save_dep_graph(tcx));
+    tcx.sess.time("serialize_dep_graph", || rustc_incremental::save_dep_graph(tcx));
 
     // We assume that no queries are run past here. If there are new queries
     // after this point, they'll show up as "<unknown>" in self-profiling data.

compiler/rustc_codegen_ssa/src/traits/mod.rs

@@ -85,7 +85,7 @@ impl<'tcx, T> CodegenMethods<'tcx> for T where
 }
 
 pub trait HasCodegen<'tcx>:
-    Backend<'tcx> + ::std::ops::Deref<Target = <Self as HasCodegen<'tcx>>::CodegenCx>
+    Backend<'tcx> + std::ops::Deref<Target = <Self as HasCodegen<'tcx>>::CodegenCx>
 {
     type CodegenCx: CodegenMethods<'tcx>
         + BackendTypes<

compiler/rustc_data_structures/src/fingerprint.rs

@@ -71,8 +71,8 @@ impl Fingerprint {
     }
 }
 
-impl ::std::fmt::Display for Fingerprint {
+impl std::fmt::Display for Fingerprint {
-    fn fmt(&self, formatter: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
+    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(formatter, "{:x}-{:x}", self.0, self.1)
     }
 }

compiler/rustc_data_structures/src/obligation_forest/mod.rs

@@ -129,7 +129,7 @@ pub enum ProcessResult<O, E> {
 struct ObligationTreeId(usize);
 
 type ObligationTreeIdGenerator =
-    ::std::iter::Map<::std::ops::RangeFrom<usize>, fn(usize) -> ObligationTreeId>;
+    std::iter::Map<std::ops::RangeFrom<usize>, fn(usize) -> ObligationTreeId>;
 
 pub struct ObligationForest<O: ForestObligation> {
     /// The list of obligations. In between calls to `process_obligations`,

compiler/rustc_data_structures/src/sorted_map.rs

@@ -93,7 +93,7 @@ impl<K: Ord, V> SortedMap<K, V> {
 
     /// Iterate over elements, sorted by key
     #[inline]
-    pub fn iter(&self) -> ::std::slice::Iter<'_, (K, V)> {
+    pub fn iter(&self) -> std::slice::Iter<'_, (K, V)> {
         self.data.iter()
     }
 
@@ -134,7 +134,7 @@ impl<K: Ord, V> SortedMap<K, V> {
         R: RangeBounds<K>,
     {
         let (start, end) = self.range_slice_indices(range);
-        self.data.splice(start..end, ::std::iter::empty());
+        self.data.splice(start..end, std::iter::empty());
     }
 
     /// Mutate all keys with the given function `f`. This mutation must not
@@ -241,7 +241,7 @@ impl<K: Ord, V> SortedMap<K, V> {
 
 impl<K: Ord, V> IntoIterator for SortedMap<K, V> {
     type Item = (K, V);
-    type IntoIter = ::std::vec::IntoIter<(K, V)>;
+    type IntoIter = std::vec::IntoIter<(K, V)>;
 
     fn into_iter(self) -> Self::IntoIter {
         self.data.into_iter()

compiler/rustc_data_structures/src/stable_hasher.rs

@@ -20,7 +20,7 @@ pub struct StableHasher {
 }
 
 impl ::std::fmt::Debug for StableHasher {
-    fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "{:?}", self.state)
     }
 }

compiler/rustc_hir/src/definitions.rs

@@ -118,7 +118,7 @@ impl DefKey {
 
         let DisambiguatedDefPathData { ref data, disambiguator } = self.disambiguated_data;
 
-        ::std::mem::discriminant(data).hash(&mut hasher);
+        std::mem::discriminant(data).hash(&mut hasher);
         if let Some(name) = data.get_opt_name() {
             // Get a stable hash by considering the symbol chars rather than
             // the symbol index.

compiler/rustc_infer/src/infer/nll_relate/mod.rs

@@ -341,7 +341,7 @@ where
         // been fully instantiated and hence the set of scopes we have
         // doesn't matter -- just to be sure, put an empty vector
         // in there.
-        let old_a_scopes = ::std::mem::take(pair.vid_scopes(self));
+        let old_a_scopes = std::mem::take(pair.vid_scopes(self));
 
         // Relate the generalized kind to the original one.
         let result = pair.relate_generalized_ty(self, generalized_ty);
@@ -680,7 +680,7 @@ where
             //   itself occurs. Note that `'b` and `'c` must both
             //   include P. At the point, the call works because of
             //   subtyping (i.e., `&'b u32 <: &{P} u32`).
-            let variance = ::std::mem::replace(&mut self.ambient_variance, ty::Variance::Covariant);
+            let variance = std::mem::replace(&mut self.ambient_variance, ty::Variance::Covariant);
 
             self.relate(a.skip_binder(), b.skip_binder())?;
 
@@ -709,7 +709,7 @@ where
             // Reset ambient variance to contravariance. See the
             // covariant case above for an explanation.
             let variance =
-                ::std::mem::replace(&mut self.ambient_variance, ty::Variance::Contravariant);
+                std::mem::replace(&mut self.ambient_variance, ty::Variance::Contravariant);
 
             self.relate(a.skip_binder(), b.skip_binder())?;
 

compiler/rustc_infer/src/infer/outlives/obligations.rs

@@ -110,7 +110,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
 
     /// Trait queries just want to pass back type obligations "as is"
     pub fn take_registered_region_obligations(&self) -> Vec<(hir::HirId, RegionObligation<'tcx>)> {
-        ::std::mem::take(&mut self.inner.borrow_mut().region_obligations)
+        std::mem::take(&mut self.inner.borrow_mut().region_obligations)
     }
 
     /// Process the region obligations that must be proven (during

compiler/rustc_middle/src/ich/impls_syntax.rs

@@ -5,7 +5,7 @@ use crate::ich::StableHashingContext;
 
 use rustc_ast as ast;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_span::SourceFile;
+use rustc_span::{BytePos, NormalizedPos, SourceFile};
 
 use smallvec::SmallVec;
 
@@ -102,22 +102,19 @@ impl<'a> HashStable<StableHashingContext<'a>> for SourceFile {
     }
 }
 
-fn stable_byte_pos(pos: ::rustc_span::BytePos, source_file_start: ::rustc_span::BytePos) -> u32 {
+fn stable_byte_pos(pos: BytePos, source_file_start: BytePos) -> u32 {
     pos.0 - source_file_start.0
 }
 
-fn stable_multibyte_char(
+fn stable_multibyte_char(mbc: rustc_span::MultiByteChar, source_file_start: BytePos) -> (u32, u32) {
-    mbc: ::rustc_span::MultiByteChar,
+    let rustc_span::MultiByteChar { pos, bytes } = mbc;
-    source_file_start: ::rustc_span::BytePos,
-) -> (u32, u32) {
-    let ::rustc_span::MultiByteChar { pos, bytes } = mbc;
 
     (pos.0 - source_file_start.0, bytes as u32)
 }
 
 fn stable_non_narrow_char(
-    swc: ::rustc_span::NonNarrowChar,
+    swc: rustc_span::NonNarrowChar,
-    source_file_start: ::rustc_span::BytePos,
+    source_file_start: BytePos,
 ) -> (u32, u32) {
     let pos = swc.pos();
     let width = swc.width();
@@ -125,11 +122,8 @@ fn stable_non_narrow_char(
     (pos.0 - source_file_start.0, width as u32)
 }
 
-fn stable_normalized_pos(
+fn stable_normalized_pos(np: NormalizedPos, source_file_start: BytePos) -> (u32, u32) {
-    np: ::rustc_span::NormalizedPos,
+    let NormalizedPos { pos, diff } = np;
-    source_file_start: ::rustc_span::BytePos,
-) -> (u32, u32) {
-    let ::rustc_span::NormalizedPos { pos, diff } = np;
 
     (pos.0 - source_file_start.0, diff)
 }

compiler/rustc_middle/src/mir/interpret/allocation.rs

@@ -40,7 +40,7 @@ pub struct Allocation<Tag = (), Extra = ()> {
     pub extra: Extra,
 }
 
-pub trait AllocationExtra<Tag>: ::std::fmt::Debug + Clone {
+pub trait AllocationExtra<Tag>: std::fmt::Debug + Clone {
     // There is no constructor in here because the constructor's type depends
     // on `MemoryKind`, and making things sufficiently generic leads to painful
     // inference failure.

compiler/rustc_middle/src/mir/interpret/value.rs

@@ -58,7 +58,7 @@ impl<'tcx> ConstValue<'tcx> {
 
     pub fn try_to_str_slice(&self) -> Option<&'tcx str> {
         if let ConstValue::Slice { data, start, end } = *self {
-            ::std::str::from_utf8(data.inspect_with_uninit_and_ptr_outside_interpreter(start..end))
+            std::str::from_utf8(data.inspect_with_uninit_and_ptr_outside_interpreter(start..end))
                 .ok()
         } else {
             None
@@ -465,7 +465,7 @@ impl<'tcx, Tag> Scalar<Tag> {
 
     pub fn to_char(self) -> InterpResult<'tcx, char> {
         let val = self.to_u32()?;
-        match ::std::char::from_u32(val) {
+        match std::char::from_u32(val) {
             Some(c) => Ok(c),
             None => throw_ub!(InvalidChar(val)),
         }

compiler/rustc_middle/src/mir/mod.rs

@@ -775,7 +775,7 @@ mod binding_form_impl {
     impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
         fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
             use super::BindingForm::*;
-            ::std::mem::discriminant(self).hash_stable(hcx, hasher);
+            std::mem::discriminant(self).hash_stable(hcx, hasher);
 
             match self {
                 Var(binding) => binding.hash_stable(hcx, hasher),

compiler/rustc_middle/src/ty/layout.rs

@@ -1894,7 +1894,7 @@ impl<'tcx, T: HasTyCtxt<'tcx>> HasTyCtxt<'tcx> for LayoutCx<'tcx, T> {
     }
 }
 
-pub type TyAndLayout<'tcx> = ::rustc_target::abi::TyAndLayout<'tcx, Ty<'tcx>>;
+pub type TyAndLayout<'tcx> = rustc_target::abi::TyAndLayout<'tcx, Ty<'tcx>>;
 
 impl<'tcx> LayoutOf for LayoutCx<'tcx, TyCtxt<'tcx>> {
     type Ty = Ty<'tcx>;

compiler/rustc_middle/src/ty/normalize_erasing_regions.rs

@@ -23,7 +23,7 @@ impl<'tcx> TyCtxt<'tcx> {
     {
         debug!(
             "normalize_erasing_regions::<{}>(value={:?}, param_env={:?})",
-            ::std::any::type_name::<T>(),
+            std::any::type_name::<T>(),
             value,
             param_env,
         );

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -1142,7 +1142,7 @@ pub trait PrettyPrinter<'tcx>:
                 // relocations (we have an active `str` reference here). We don't use this
                 // result to affect interpreter execution.
                 let slice = data.inspect_with_uninit_and_ptr_outside_interpreter(start..end);
-                let s = ::std::str::from_utf8(slice).expect("non utf8 str from miri");
+                let s = std::str::from_utf8(slice).expect("non utf8 str from miri");
                 p!(write("{:?}", s));
                 Ok(self)
             }

compiler/rustc_middle/src/ty/query/on_disk_cache.rs

@@ -543,7 +543,7 @@ impl<'a, 'tcx> DecoderWithPosition for CacheDecoder<'a, 'tcx> {
 // tag matches and the correct amount of bytes was read.
 fn decode_tagged<D, T, V>(decoder: &mut D, expected_tag: T) -> Result<V, D::Error>
 where
-    T: Decodable<D> + Eq + ::std::fmt::Debug,
+    T: Decodable<D> + Eq + std::fmt::Debug,
     V: Decodable<D>,
     D: DecoderWithPosition,
 {
@@ -1023,7 +1023,7 @@ where
     let _timer = tcx
         .sess
         .prof
-        .extra_verbose_generic_activity("encode_query_results_for", ::std::any::type_name::<Q>());
+        .extra_verbose_generic_activity("encode_query_results_for", std::any::type_name::<Q>());
 
     let state = Q::query_state(tcx);
     assert!(state.all_inactive());

compiler/rustc_middle/src/ty/util.rs

@@ -646,8 +646,8 @@ impl<'tcx> ty::TyS<'tcx> {
             }
             ty::Char => Some(std::char::MAX as u128),
             ty::Float(fty) => Some(match fty {
-                ast::FloatTy::F32 => ::rustc_apfloat::ieee::Single::INFINITY.to_bits(),
+                ast::FloatTy::F32 => rustc_apfloat::ieee::Single::INFINITY.to_bits(),
-                ast::FloatTy::F64 => ::rustc_apfloat::ieee::Double::INFINITY.to_bits(),
+                ast::FloatTy::F64 => rustc_apfloat::ieee::Double::INFINITY.to_bits(),
             }),
             _ => None,
         };

compiler/rustc_mir/src/interpret/machine.rs

@@ -3,6 +3,7 @@
 //! interpreting common C functions leak into CTFE.
 
 use std::borrow::{Borrow, Cow};
+use std::fmt::Debug;
 use std::hash::Hash;
 
 use rustc_middle::mir;
@@ -79,19 +80,19 @@ pub trait AllocMap<K: Hash + Eq, V> {
 /// and some use case dependent behaviour can instead be applied.
 pub trait Machine<'mir, 'tcx>: Sized {
     /// Additional memory kinds a machine wishes to distinguish from the builtin ones
-    type MemoryKind: ::std::fmt::Debug + ::std::fmt::Display + MayLeak + Eq + 'static;
+    type MemoryKind: Debug + std::fmt::Display + MayLeak + Eq + 'static;
 
     /// Tag tracked alongside every pointer. This is used to implement "Stacked Borrows"
     /// <https://www.ralfj.de/blog/2018/08/07/stacked-borrows.html>.
     /// The `default()` is used for pointers to consts, statics, vtables and functions.
     /// The `Debug` formatting is used for displaying pointers; we cannot use `Display`
     /// as `()` does not implement that, but it should be "nice" output.
-    type PointerTag: ::std::fmt::Debug + Copy + Eq + Hash + 'static;
+    type PointerTag: Debug + Copy + Eq + Hash + 'static;
 
     /// Machines can define extra (non-instance) things that represent values of function pointers.
     /// For example, Miri uses this to return a function pointer from `dlsym`
     /// that can later be called to execute the right thing.
-    type ExtraFnVal: ::std::fmt::Debug + Copy;
+    type ExtraFnVal: Debug + Copy;
 
     /// Extra data stored in every call frame.
     type FrameExtra;

compiler/rustc_mir/src/interpret/operand.rs

@@ -133,7 +133,7 @@ impl<Tag: Copy> std::fmt::Display for ImmTy<'tcx, Tag> {
     }
 }
 
-impl<'tcx, Tag> ::std::ops::Deref for ImmTy<'tcx, Tag> {
+impl<'tcx, Tag> std::ops::Deref for ImmTy<'tcx, Tag> {
     type Target = Immediate<Tag>;
     #[inline(always)]
     fn deref(&self) -> &Immediate<Tag> {
@@ -156,7 +156,7 @@ pub struct OpTy<'tcx, Tag = ()> {
     pub layout: TyAndLayout<'tcx>,
 }
 
-impl<'tcx, Tag> ::std::ops::Deref for OpTy<'tcx, Tag> {
+impl<'tcx, Tag> std::ops::Deref for OpTy<'tcx, Tag> {
     type Target = Operand<Tag>;
     #[inline(always)]
     fn deref(&self) -> &Operand<Tag> {
@@ -340,7 +340,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     pub fn read_str(&self, mplace: MPlaceTy<'tcx, M::PointerTag>) -> InterpResult<'tcx, &str> {
         let len = mplace.len(self)?;
         let bytes = self.memory.read_bytes(mplace.ptr, Size::from_bytes(len))?;
-        let str = ::std::str::from_utf8(bytes).map_err(|err| err_ub!(InvalidStr(err)))?;
+        let str = std::str::from_utf8(bytes).map_err(|err| err_ub!(InvalidStr(err)))?;
         Ok(str)
     }
 

compiler/rustc_mir/src/interpret/place.rs

@@ -3,6 +3,7 @@
 //! All high-level functions to write to memory work on places as destinations.
 
 use std::convert::TryFrom;
+use std::fmt::Debug;
 use std::hash::Hash;
 
 use rustc_macros::HashStable;
@@ -86,7 +87,7 @@ pub struct PlaceTy<'tcx, Tag = ()> {
     pub layout: TyAndLayout<'tcx>,
 }
 
-impl<'tcx, Tag> ::std::ops::Deref for PlaceTy<'tcx, Tag> {
+impl<'tcx, Tag> std::ops::Deref for PlaceTy<'tcx, Tag> {
     type Target = Place<Tag>;
     #[inline(always)]
     fn deref(&self) -> &Place<Tag> {
@@ -101,7 +102,7 @@ pub struct MPlaceTy<'tcx, Tag = ()> {
     pub layout: TyAndLayout<'tcx>,
 }
 
-impl<'tcx, Tag> ::std::ops::Deref for MPlaceTy<'tcx, Tag> {
+impl<'tcx, Tag> std::ops::Deref for MPlaceTy<'tcx, Tag> {
     type Target = MemPlace<Tag>;
     #[inline(always)]
     fn deref(&self) -> &MemPlace<Tag> {
@@ -226,7 +227,7 @@ impl<'tcx, Tag> MPlaceTy<'tcx, Tag> {
 }
 
 // These are defined here because they produce a place.
-impl<'tcx, Tag: ::std::fmt::Debug + Copy> OpTy<'tcx, Tag> {
+impl<'tcx, Tag: Debug + Copy> OpTy<'tcx, Tag> {
     #[inline(always)]
     /// Note: do not call `as_ref` on the resulting place. This function should only be used to
     /// read from the resulting mplace, not to get its address back.
@@ -251,7 +252,7 @@ impl<'tcx, Tag: ::std::fmt::Debug + Copy> OpTy<'tcx, Tag> {
     }
 }
 
-impl<Tag: ::std::fmt::Debug> Place<Tag> {
+impl<Tag: Debug> Place<Tag> {
     #[inline]
     pub fn assert_mem_place(self) -> MemPlace<Tag> {
         match self {
@@ -261,7 +262,7 @@ impl<Tag: ::std::fmt::Debug> Place<Tag> {
     }
 }
 
-impl<'tcx, Tag: ::std::fmt::Debug> PlaceTy<'tcx, Tag> {
+impl<'tcx, Tag: Debug> PlaceTy<'tcx, Tag> {
     #[inline]
     pub fn assert_mem_place(self) -> MPlaceTy<'tcx, Tag> {
         MPlaceTy { mplace: self.place.assert_mem_place(), layout: self.layout }
@@ -272,7 +273,7 @@ impl<'tcx, Tag: ::std::fmt::Debug> PlaceTy<'tcx, Tag> {
 impl<'mir, 'tcx: 'mir, Tag, M> InterpCx<'mir, 'tcx, M>
 where
     // FIXME: Working around https://github.com/rust-lang/rust/issues/54385
-    Tag: ::std::fmt::Debug + Copy + Eq + Hash + 'static,
+    Tag: Debug + Copy + Eq + Hash + 'static,
     M: Machine<'mir, 'tcx, PointerTag = Tag>,
     // FIXME: Working around https://github.com/rust-lang/rust/issues/24159
     M::MemoryMap: AllocMap<AllocId, (MemoryKind<M::MemoryKind>, Allocation<Tag, M::AllocExtra>)>,

compiler/rustc_mir/src/transform/mod.rs

@@ -137,7 +137,7 @@ fn mir_keys(tcx: TyCtxt<'_>, krate: CrateNum) -> FxHashSet<LocalDefId> {
 /// Generates a default name for the pass based on the name of the
 /// type `T`.
 pub fn default_name<T: ?Sized>() -> Cow<'static, str> {
-    let name = ::std::any::type_name::<T>();
+    let name = std::any::type_name::<T>();
     if let Some(tail) = name.rfind(':') { Cow::from(&name[tail + 1..]) } else { Cow::from(name) }
 }
 

compiler/rustc_mir_build/src/thir/pattern/check_match.rs

@@ -96,14 +96,14 @@ impl PatCtxt<'_, '_> {
                 }
                 PatternError::FloatBug => {
                     // FIXME(#31407) this is only necessary because float parsing is buggy
-                    ::rustc_middle::mir::interpret::struct_error(
+                    rustc_middle::mir::interpret::struct_error(
                         self.tcx.at(pat_span),
                         "could not evaluate float literal (see issue #31407)",
                     )
                     .emit();
                 }
                 PatternError::NonConstPath(span) => {
-                    ::rustc_middle::mir::interpret::struct_error(
+                    rustc_middle::mir::interpret::struct_error(
                         self.tcx.at(span),
                         "runtime values cannot be referenced in patterns",
                     )

compiler/rustc_mir_build/src/thir/pattern/mod.rs

@@ -1060,13 +1060,13 @@ crate fn compare_const_vals<'tcx>(
         use rustc_apfloat::Float;
         return match *ty.kind() {
             ty::Float(ast::FloatTy::F32) => {
-                let l = ::rustc_apfloat::ieee::Single::from_bits(a);
+                let l = rustc_apfloat::ieee::Single::from_bits(a);
-                let r = ::rustc_apfloat::ieee::Single::from_bits(b);
+                let r = rustc_apfloat::ieee::Single::from_bits(b);
                 l.partial_cmp(&r)
             }
             ty::Float(ast::FloatTy::F64) => {
-                let l = ::rustc_apfloat::ieee::Double::from_bits(a);
+                let l = rustc_apfloat::ieee::Double::from_bits(a);
-                let r = ::rustc_apfloat::ieee::Double::from_bits(b);
+                let r = rustc_apfloat::ieee::Double::from_bits(b);
                 l.partial_cmp(&r)
             }
             ty::Int(ity) => {

compiler/rustc_resolve/src/diagnostics.rs

@@ -469,24 +469,17 @@ impl<'a> Resolver<'a> {
             ResolutionError::ParamInNonTrivialAnonConst { name, is_type } => {
                 let mut err = self.session.struct_span_err(
                     span,
-                    "generic parameters must not be used inside of non-trivial constant values",
+                    "generic parameters may not be used in const operations",
-                );
-                err.span_label(
-                    span,
-                    &format!(
-                        "non-trivial anonymous constants must not depend on the parameter `{}`",
-                        name
-                    ),
                 );
+                err.span_label(span, &format!("cannot perform const operation using `{}`", name));
 
                 if is_type {
-                    err.note("type parameters are currently not permitted in anonymous constants");
+                    err.note("type parameters may not be used in const expressions");
                 } else {
-                    err.help(
+                    err.help(&format!(
-                        &format!("it is currently only allowed to use either `{0}` or `{{ {0} }}` as generic constants",
+                        "const parameters may only be used as standalone arguments, i.e. `{}`",
-                                 name
+                        name
-                        )
+                    ));
-                    );
                 }
 
                 err

compiler/rustc_resolve/src/lib.rs

@@ -218,7 +218,7 @@ enum ResolutionError<'a> {
     ParamInTyOfConstParam(Symbol),
     /// constant values inside of type parameter defaults must not depend on generic parameters.
     ParamInAnonConstInTyDefault(Symbol),
-    /// generic parameters must not be used inside of non-trivial constant values.
+    /// generic parameters must not be used inside const evaluations.
     ///
     /// This error is only emitted when using `min_const_generics`.
     ParamInNonTrivialAnonConst { name: Symbol, is_type: bool },

compiler/rustc_serialize/src/opaque.rs

@@ -107,7 +107,7 @@ impl serialize::Encoder for Encoder {
 
     #[inline]
     fn emit_i8(&mut self, v: i8) -> EncodeResult {
-        let as_u8: u8 = unsafe { ::std::mem::transmute(v) };
+        let as_u8: u8 = unsafe { std::mem::transmute(v) };
         self.emit_u8(as_u8)
     }
 
@@ -300,13 +300,13 @@ impl<'a> serialize::Decoder for Decoder<'a> {
     #[inline]
     fn read_char(&mut self) -> Result<char, Self::Error> {
         let bits = self.read_u32()?;
-        Ok(::std::char::from_u32(bits).unwrap())
+        Ok(std::char::from_u32(bits).unwrap())
     }
 
     #[inline]
     fn read_str(&mut self) -> Result<Cow<'_, str>, Self::Error> {
         let len = self.read_usize()?;
-        let s = ::std::str::from_utf8(&self.data[self.position..self.position + len]).unwrap();
+        let s = std::str::from_utf8(&self.data[self.position..self.position + len]).unwrap();
         self.position += len;
         Ok(Cow::Borrowed(s))
     }

compiler/rustc_symbol_mangling/src/v0.rs

@@ -132,7 +132,7 @@ impl SymbolMangler<'tcx> {
             self.push("u");
 
             // FIXME(eddyb) we should probably roll our own punycode implementation.
-            let mut punycode_bytes = match ::punycode::encode(ident) {
+            let mut punycode_bytes = match punycode::encode(ident) {
                 Ok(s) => s.into_bytes(),
                 Err(()) => bug!("symbol_names: punycode encoding failed for ident {:?}", ident),
             };

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -22,6 +22,7 @@ use rustc_middle::ty::{
 use rustc_middle::ty::{TypeAndMut, TypeckResults};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{MultiSpan, Span, DUMMY_SP};
+use rustc_target::spec::abi;
 use std::fmt;
 
 use super::InferCtxtPrivExt;
@@ -1157,15 +1158,15 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                     tcx.mk_ty_infer(ty::TyVar(ty::TyVid { index: 0 })),
                     false,
                     hir::Unsafety::Normal,
-                    ::rustc_target::spec::abi::Abi::Rust,
+                    abi::Abi::Rust,
                 )
             } else {
                 tcx.mk_fn_sig(
-                    ::std::iter::once(inputs),
+                    std::iter::once(inputs),
                     tcx.mk_ty_infer(ty::TyVar(ty::TyVid { index: 0 })),
                     false,
                     hir::Unsafety::Normal,
-                    ::rustc_target::spec::abi::Abi::Rust,
+                    abi::Abi::Rust,
                 )
             };
             ty::Binder::bind(sig).to_string()

compiler/rustc_trait_selection/src/traits/query/normalize.rs

@@ -44,7 +44,7 @@ impl<'cx, 'tcx> AtExt<'tcx> for At<'cx, 'tcx> {
     {
         debug!(
             "normalize::<{}>(value={:?}, param_env={:?})",
-            ::std::any::type_name::<T>(),
+            std::any::type_name::<T>(),
             value,
             self.param_env,
         );
@@ -65,13 +65,13 @@ impl<'cx, 'tcx> AtExt<'tcx> for At<'cx, 'tcx> {
         let result = value.fold_with(&mut normalizer);
         debug!(
             "normalize::<{}>: result={:?} with {} obligations",
-            ::std::any::type_name::<T>(),
+            std::any::type_name::<T>(),
             result,
             normalizer.obligations.len(),
         );
         debug!(
             "normalize::<{}>: obligations={:?}",
-            ::std::any::type_name::<T>(),
+            std::any::type_name::<T>(),
             normalizer.obligations,
         );
         if normalizer.error {

library/alloc/src/collections/btree/node.rs

@@ -170,6 +170,22 @@ impl<K, V> Root<K, V> {
         NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData }
     }
 
+    /// Borrows and returns a mutable reference to the leaf node owned by the root.
+    /// # Safety
+    /// The root node is a leaf.
+    unsafe fn leaf_node_as_mut(&mut self) -> NodeRef<marker::Mut<'_>, K, V, marker::Leaf> {
+        debug_assert!(self.height == 0);
+        NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData }
+    }
+
+    /// Borrows and returns a mutable reference to the internal node owned by the root.
+    /// # Safety
+    /// The root node is not a leaf.
+    unsafe fn internal_node_as_mut(&mut self) -> NodeRef<marker::Mut<'_>, K, V, marker::Internal> {
+        debug_assert!(self.height > 0);
+        NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData }
+    }
+
     pub fn node_as_valmut(&mut self) -> NodeRef<marker::ValMut<'_>, K, V, marker::LeafOrInternal> {
         NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData }
     }
@@ -188,14 +204,11 @@ impl<K, V> Root<K, V> {
         self.node = BoxedNode::from_internal(new_node);
         self.height += 1;
 
-        let mut ret =
-            NodeRef { height: self.height, node: self.node.as_ptr(), _marker: PhantomData };
-
         unsafe {
+            let mut ret = self.internal_node_as_mut();
             ret.reborrow_mut().first_edge().correct_parent_link();
+            ret
         }
-
-        ret
     }
 
     /// Removes the internal root node, using its first child as the new root node.
@@ -212,11 +225,8 @@ impl<K, V> Root<K, V> {
 
         let top = self.node.ptr;
 
-        self.node = unsafe {
+        let internal_node = unsafe { self.internal_node_as_mut() };
-            BoxedNode::from_ptr(
+        self.node = unsafe { BoxedNode::from_ptr(internal_node.first_edge().descend().node) };
-                self.node_as_mut().cast_unchecked::<marker::Internal>().first_edge().descend().node,
-            )
-        };
         self.height -= 1;
         self.node_as_mut().as_leaf_mut().parent = None;
 
@@ -443,9 +453,9 @@ impl<K, V> NodeRef<marker::Owned, K, V, marker::LeafOrInternal> {
 }
 
 impl<'a, K, V, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
-    /// Unsafely asserts to the compiler some static information about whether this
+    /// Unsafely asserts to the compiler the static information that this node is an `Internal`.
-    /// node is a `Leaf` or an `Internal`.
+    unsafe fn cast_to_internal_unchecked(self) -> NodeRef<marker::Mut<'a>, K, V, marker::Internal> {
-    unsafe fn cast_unchecked<NewType>(self) -> NodeRef<marker::Mut<'a>, K, V, NewType> {
+        debug_assert!(self.height > 0);
         NodeRef { height: self.height, node: self.node, _marker: PhantomData }
     }
 
@@ -943,10 +953,7 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, mark
                     Handle::new_edge(left.reborrow_mut(), insert_idx)
                 },
                 InsertionPlace::Right(insert_idx) => unsafe {
-                    Handle::new_edge(
+                    Handle::new_edge(right.leaf_node_as_mut(), insert_idx)
-                        right.node_as_mut().cast_unchecked::<marker::Leaf>(),
-                        insert_idx,
-                    )
                 },
             };
             let val_ptr = insertion_edge.insert_fit(key, val);
@@ -1006,10 +1013,7 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>,
                     Handle::new_edge(left.reborrow_mut(), insert_idx)
                 },
                 InsertionPlace::Right(insert_idx) => unsafe {
-                    Handle::new_edge(
+                    Handle::new_edge(right.internal_node_as_mut(), insert_idx)
-                        right.node_as_mut().cast_unchecked::<marker::Internal>(),
-                        insert_idx,
-                    )
                 },
             };
             insertion_edge.insert_fit(key, val, edge);
@@ -1205,7 +1209,7 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>,
 
             let mut new_root = Root { node: BoxedNode::from_internal(new_node), height };
 
-            new_root.node_as_mut().cast_unchecked().correct_childrens_parent_links(0..=new_len);
+            new_root.internal_node_as_mut().correct_childrens_parent_links(0..=new_len);
 
             (self.node, k, v, new_root)
         }
@@ -1258,8 +1262,8 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>,
             if self.node.height > 1 {
                 // SAFETY: the height of the nodes being merged is one below the height
                 // of the node of this edge, thus above zero, so they are internal.
-                let mut left_node = left_node.cast_unchecked::<marker::Internal>();
+                let mut left_node = left_node.cast_to_internal_unchecked();
-                let right_node = right_node.cast_unchecked::<marker::Internal>();
+                let right_node = right_node.cast_to_internal_unchecked();
                 ptr::copy_nonoverlapping(
                     right_node.edge_at(0),
                     left_node.edges_mut().as_mut_ptr().add(left_len + 1),

library/core/tests/num/int_macros.rs

@@ -204,8 +204,8 @@ macro_rules! int_module {
 
             #[test]
             fn test_from_str() {
-                fn from_str<T: ::std::str::FromStr>(t: &str) -> Option<T> {
+                fn from_str<T: std::str::FromStr>(t: &str) -> Option<T> {
-                    ::std::str::FromStr::from_str(t).ok()
+                    std::str::FromStr::from_str(t).ok()
                 }
                 assert_eq!(from_str::<$T>("0"), Some(0 as $T));
                 assert_eq!(from_str::<$T>("3"), Some(3 as $T));

library/std/src/sys/unsupported/common.rs

@@ -39,10 +39,13 @@ pub fn hashmap_random_keys() -> (u64, u64) {
 pub enum Void {}
 
 pub unsafe fn strlen(mut s: *const c_char) -> usize {
-    let mut n = 0;
+    // SAFETY: The caller must guarantee `s` points to a valid 0-terminated string.
-    while *s != 0 {
+    unsafe {
-        n += 1;
+        let mut n = 0;
-        s = s.offset(1);
+        while *s != 0 {
+            n += 1;
+            s = s.offset(1);
+        }
+        n
     }
-    return n;
 }

library/std/src/sys/unsupported/mod.rs

@@ -1,3 +1,5 @@
+#![deny(unsafe_op_in_unsafe_fn)]
+
 pub mod alloc;
 pub mod args;
 pub mod cmath;

library/std/src/sys/unsupported/mutex.rs

@@ -1,7 +1,8 @@
-use crate::cell::UnsafeCell;
+use crate::cell::Cell;
 
 pub struct Mutex {
-    locked: UnsafeCell<bool>,
+    // This platform has no threads, so we can use a Cell here.
+    locked: Cell<bool>,
 }
 
 pub type MovableMutex = Mutex;
@@ -10,9 +11,8 @@ unsafe impl Send for Mutex {}
 unsafe impl Sync for Mutex {} // no threads on this platform
 
 impl Mutex {
-    #[rustc_const_stable(feature = "const_sys_mutex_new", since = "1.0.0")]
     pub const fn new() -> Mutex {
-        Mutex { locked: UnsafeCell::new(false) }
+        Mutex { locked: Cell::new(false) }
     }
 
     #[inline]
@@ -20,25 +20,17 @@ impl Mutex {
 
     #[inline]
     pub unsafe fn lock(&self) {
-        let locked = self.locked.get();
+        assert_eq!(self.locked.replace(true), false, "cannot recursively acquire mutex");
-        assert!(!*locked, "cannot recursively acquire mutex");
-        *locked = true;
     }
 
     #[inline]
     pub unsafe fn unlock(&self) {
-        *self.locked.get() = false;
+        self.locked.set(false);
     }
 
     #[inline]
     pub unsafe fn try_lock(&self) -> bool {
-        let locked = self.locked.get();
+        self.locked.replace(true) == false
-        if *locked {
-            false
-        } else {
-            *locked = true;
-            true
-        }
     }
 
     #[inline]

library/std/src/sys/unsupported/rwlock.rs

@@ -1,7 +1,8 @@
-use crate::cell::UnsafeCell;
+use crate::cell::Cell;
 
 pub struct RWLock {
-    mode: UnsafeCell<isize>,
+    // This platform has no threads, so we can use a Cell here.
+    mode: Cell<isize>,
 }
 
 unsafe impl Send for RWLock {}
@@ -9,14 +10,14 @@ unsafe impl Sync for RWLock {} // no threads on this platform
 
 impl RWLock {
     pub const fn new() -> RWLock {
-        RWLock { mode: UnsafeCell::new(0) }
+        RWLock { mode: Cell::new(0) }
     }
 
     #[inline]
     pub unsafe fn read(&self) {
-        let mode = self.mode.get();
+        let m = self.mode.get();
-        if *mode >= 0 {
+        if m >= 0 {
-            *mode += 1;
+            self.mode.set(m + 1);
         } else {
             rtabort!("rwlock locked for writing");
         }
@@ -24,9 +25,9 @@ impl RWLock {
 
     #[inline]
     pub unsafe fn try_read(&self) -> bool {
-        let mode = self.mode.get();
+        let m = self.mode.get();
-        if *mode >= 0 {
+        if m >= 0 {
-            *mode += 1;
+            self.mode.set(m + 1);
             true
         } else {
             false
@@ -35,19 +36,15 @@ impl RWLock {
 
     #[inline]
     pub unsafe fn write(&self) {
-        let mode = self.mode.get();
+        if self.mode.replace(-1) != 0 {
-        if *mode == 0 {
-            *mode = -1;
-        } else {
             rtabort!("rwlock locked for reading")
         }
     }
 
     #[inline]
     pub unsafe fn try_write(&self) -> bool {
-        let mode = self.mode.get();
+        if self.mode.get() == 0 {
-        if *mode == 0 {
+            self.mode.set(-1);
-            *mode = -1;
             true
         } else {
             false
@@ -56,12 +53,12 @@ impl RWLock {
 
     #[inline]
     pub unsafe fn read_unlock(&self) {
-        *self.mode.get() -= 1;
+        self.mode.set(self.mode.get() - 1);
     }
 
     #[inline]
     pub unsafe fn write_unlock(&self) {
-        *self.mode.get() += 1;
+        assert_eq!(self.mode.replace(0), -1);
     }
 
     #[inline]

library/std/src/sys/wasi/mod.rs

@@ -53,6 +53,7 @@ pub mod thread_local_key;
 pub mod time;
 
 #[path = "../unsupported/common.rs"]
+#[deny(unsafe_op_in_unsafe_fn)]
 #[allow(unused)]
 mod common;
 pub use common::*;

library/std/src/sys/wasm/mod.rs

@@ -66,5 +66,6 @@ cfg_if::cfg_if! {
 }
 
 #[path = "../unsupported/common.rs"]
+#[deny(unsafe_op_in_unsafe_fn)]
 mod common;
 pub use common::*;

library/std/src/sys_common/mutex.rs

@@ -21,7 +21,6 @@ impl StaticMutex {
     /// first used with any of the functions below.
     /// Also, the behavior is undefined if this mutex is ever used reentrantly,
     /// i.e., `lock` is called by the thread currently holding the lock.
-    #[rustc_const_stable(feature = "const_sys_mutex_new", since = "1.0.0")]
     pub const fn new() -> Self {
         Self(imp::Mutex::new())
     }

library/test/src/formatters/json.rs

@@ -182,8 +182,8 @@ impl<T: Write> OutputFormatter for JsonFormatter<T> {
 /// Base code taken form `libserialize::json::escape_str`
 struct EscapedString<S: AsRef<str>>(S);
 
-impl<S: AsRef<str>> ::std::fmt::Display for EscapedString<S> {
+impl<S: AsRef<str>> std::fmt::Display for EscapedString<S> {
-    fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> ::std::fmt::Result {
         let mut start = 0;
 
         for (i, byte) in self.0.as_ref().bytes().enumerate() {

src/bootstrap/dist.rs

@@ -2617,7 +2617,7 @@ impl Step for BuildManifest {
         let image_bin = image.join("bin");
         let _ = fs::remove_dir_all(&image);
         t!(fs::create_dir_all(&image_bin));
-        builder.install(&build_manifest, &image_bin.join("build-manifest"), 0o755);
+        builder.install(&build_manifest, &image_bin, 0o755);
 
         // Prepare the overlay.
         let overlay = tmp.join("build-manifest-overlay");

src/bootstrap/lib.rs

@@ -177,6 +177,9 @@ const LLVM_TOOLS: &[&str] = &[
     "llvm-size", // used to prints the size of the linker sections of a program
     "llvm-strip", // used to discard symbols from binary files to reduce their size
     "llvm-ar", // used for creating and modifying archive files
+    "llvm-dis", // used to disassemble LLVM bitcode
+    "llc",     // used to compile LLVM bytecode
+    "opt",     // used to optimize LLVM bytecode
 ];
 
 pub const VERSION: usize = 2;

src/bootstrap/setup.rs

@@ -30,7 +30,7 @@ impl FromStr for Profile {
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         match s {
             "a" | "lib" | "library" => Ok(Profile::Library),
-            "b" | "compiler" => Ok(Profile::Compiler),
+            "b" | "compiler" | "rustdoc" => Ok(Profile::Compiler),
             "c" | "llvm" | "codegen" => Ok(Profile::Codegen),
             "d" | "maintainer" | "user" => Ok(Profile::User),
             _ => Err(format!("unknown profile: '{}'", s)),
@@ -108,7 +108,7 @@ pub fn interactive_path() -> io::Result<Profile> {
     println!(
         "Welcome to the Rust project! What do you want to do with x.py?
 a) Contribute to the standard library
-b) Contribute to the compiler
+b) Contribute to the compiler or rustdoc
 c) Contribute to the compiler, and also modify LLVM or codegen
 d) Install Rust from source"
     );

src/bootstrap/test.rs

@@ -966,6 +966,15 @@ impl Step for Compiletest {
     /// compiletest `mode` and `suite` arguments. For example `mode` can be
     /// "run-pass" or `suite` can be something like `debuginfo`.
     fn run(self, builder: &Builder<'_>) {
+        if builder.top_stage == 0 && env::var("COMPILETEST_FORCE_STAGE0").is_err() {
+            eprintln!("\
+error: `--stage 0` runs compiletest on the beta compiler, not your local changes, and will almost always cause tests to fail
+help: use `--stage 1` instead
+note: if you're sure you want to do this, please open an issue as to why. In the meantime, you can override this with `COMPILETEST_FORCE_STAGE0=1`."
+            );
+            std::process::exit(1);
+        }
+
         let compiler = self.compiler;
         let target = self.target;
         let mode = self.mode;

src/ci/github-actions/ci.yml

@@ -469,11 +469,11 @@ jobs:
                 --build=x86_64-apple-darwin
                 --host=aarch64-apple-darwin
                 --target=aarch64-apple-darwin
+                --enable-full-tools
                 --enable-sanitizers
                 --enable-profiler
                 --set rust.jemalloc
                 --set llvm.ninja=false
-                --tools=rls,clippy,rustfmt,analysis,src
               RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
               SELECT_XCODE: /Applications/Xcode_12_beta.app
               USE_XCODE_CLANG: 1
@@ -481,12 +481,15 @@ jobs:
               MACOSX_STD_DEPLOYMENT_TARGET: 11.0
               NO_LLVM_ASSERTIONS: 1
               NO_DEBUG_ASSERTIONS: 1
-              # TODO: Cargo is disabled until OpenSSL 1.1.1 can be
+              DIST_REQUIRE_ALL_TOOLS: 1
-              # compiled for aarch64-apple-darwin::
+              # Corresponds to 16K page size
-              # https://github.com/openssl/openssl/pull/12369. Once
+              #
-              # fixed, remove `--tools`, add back
+              # Shouldn't be needed if jemalloc-sys is updated to
-              # `--enable-full-tools`, and enable this again
+              # handle this platform like iOS or if we build on
-              # DIST_REQUIRE_ALL_TOOLS: 1
+              # aarch64-apple-darwin itself.
+              #
+              # https://github.com/gnzlbg/jemallocator/blob/c27a859e98e3cb790dc269773d9da71a1e918458/jemalloc-sys/build.rs#L237
+              JEMALLOC_SYS_WITH_LG_PAGE: 14
             <<: *job-macos-xl
 
           ######################

src/doc/rustc/src/platform-support.md

@@ -57,7 +57,7 @@ Specifically, these platforms are required to have each of the following:
 
 target | std | host | notes
 -------|-----|------|-------
-`aarch64-apple-darwin` | ✓ |  | ARM64 macOS (11.0+, Big Sur+)
+`aarch64-apple-darwin` | ✓ | ✓ | ARM64 macOS (11.0+, Big Sur+)
 `aarch64-apple-ios` | ✓ |  | ARM64 iOS
 `aarch64-fuchsia` | ✓ |  | ARM64 Fuchsia
 `aarch64-linux-android` | ✓ |  | ARM64 Android

src/test/ui/const-generics/array-size-in-generic-struct-param.min.stderr

@@ -1,18 +1,18 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/array-size-in-generic-struct-param.rs:9:48
    |
 LL | struct ArithArrayLen<const N: usize>([u32; 0 + N]);
-   |                                                ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                                                ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/array-size-in-generic-struct-param.rs:20:15
    |
 LL |     arr: [u8; CFG.arr_size],
-   |               ^^^ non-trivial anonymous constants must not depend on the parameter `CFG`
+   |               ^^^ cannot perform const operation using `CFG`
    |
-   = help: it is currently only allowed to use either `CFG` or `{ CFG }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `CFG`
 
 error: `Config` is forbidden as the type of a const generic parameter
   --> $DIR/array-size-in-generic-struct-param.rs:18:21

src/test/ui/const-generics/array-size-in-generic-struct-param.rs

@@ -8,7 +8,7 @@
 #[allow(dead_code)]
 struct ArithArrayLen<const N: usize>([u32; 0 + N]);
 //[full]~^ ERROR constant expression depends on a generic parameter
-//[min]~^^ ERROR generic parameters must not be used inside of non-trivial constant values
+//[min]~^^ ERROR generic parameters may not be used in const operations
 
 #[derive(PartialEq, Eq)]
 struct Config {
@@ -19,7 +19,7 @@ struct B<const CFG: Config> {
     //[min]~^ ERROR `Config` is forbidden
     arr: [u8; CFG.arr_size],
     //[full]~^ ERROR constant expression depends on a generic parameter
-    //[min]~^^ ERROR generic parameters must not be used inside of non-trivial
+    //[min]~^^ ERROR generic parameters may not be used in const operations
 }
 
 const C: Config = Config { arr_size: 5 };

src/test/ui/const-generics/const-argument-if-length.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/const-argument-if-length.rs:19:24
    |
 LL |     pad: [u8; is_zst::<T>()],
-   |                        ^ non-trivial anonymous constants must not depend on the parameter `T`
+   |                        ^ cannot perform const operation using `T`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
 error[E0277]: the size for values of type `T` cannot be known at compilation time
   --> $DIR/const-argument-if-length.rs:17:12

src/test/ui/const-generics/const-argument-if-length.rs

@@ -17,7 +17,7 @@ pub struct AtLeastByte<T: ?Sized> {
     value: T,
     //~^ ERROR the size for values of type `T` cannot be known at compilation time
     pad: [u8; is_zst::<T>()],
-    //[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~^ ERROR generic parameters may not be used in const operations
     //[full]~^^ ERROR evaluation of constant value failed
 }
 

src/test/ui/const-generics/const_evaluatable_checked/feature-gate-const_evaluatable_checked.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/feature-gate-const_evaluatable_checked.rs:6:33
    |
 LL | type Arr<const N: usize> = [u8; N - 1];
-   |                                 ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                                 ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error: aborting due to previous error
 

src/test/ui/const-generics/const_evaluatable_checked/feature-gate-const_evaluatable_checked.rs

@@ -4,7 +4,7 @@
 #![cfg_attr(min, feature(min_const_generics))]
 
 type Arr<const N: usize> = [u8; N - 1];
-//[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+//[min]~^ ERROR generic parameters may not be used in const operations
 
 fn test<const N: usize>() -> Arr<N> where Arr<N>: Default {
     //[full]~^ ERROR constant expression depends

src/test/ui/const-generics/const_evaluatable_checked/simple.min.stderr

@@ -1,18 +1,18 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/simple.rs:8:53
    |
 LL | fn test<const N: usize>() -> [u8; N - 1] where [u8; N - 1]: Default {
-   |                                                     ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                                                     ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/simple.rs:8:35
    |
 LL | fn test<const N: usize>() -> [u8; N - 1] where [u8; N - 1]: Default {
-   |                                   ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                                   ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error: aborting due to 2 previous errors
 

src/test/ui/const-generics/const_evaluatable_checked/simple_fail.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/simple_fail.rs:7:33
    |
 LL | type Arr<const N: usize> = [u8; N - 1];
-   |                                 ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                                 ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error: aborting due to previous error
 

src/test/ui/const-generics/const_evaluatable_checked/simple_fail.rs

@@ -5,7 +5,7 @@
 #![allow(incomplete_features)]
 
 type Arr<const N: usize> = [u8; N - 1]; //[full]~ ERROR evaluation of constant
-//[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+//[min]~^ ERROR generic parameters may not be used in const operations
 
 fn test<const N: usize>() -> Arr<N> where Arr<N>: Sized {
     todo!()

src/test/ui/const-generics/generic-function-call-in-array-length.min.stderr

@@ -1,18 +1,18 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/generic-function-call-in-array-length.rs:9:39
    |
 LL | fn bar<const N: usize>() -> [u32; foo(N)] {
-   |                                       ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                                       ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/generic-function-call-in-array-length.rs:12:13
    |
 LL |     [0; foo(N)]
-   |             ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |             ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error: aborting due to 2 previous errors
 

src/test/ui/const-generics/generic-function-call-in-array-length.rs

@@ -7,10 +7,10 @@
 const fn foo(n: usize) -> usize { n * 2 }
 
 fn bar<const N: usize>() -> [u32; foo(N)] {
-    //[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~^ ERROR generic parameters may not be used in const operations
     //[full]~^^ ERROR constant expression depends on a generic parameter
     [0; foo(N)]
-    //[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~^ ERROR generic parameters may not be used in const operations
 }
 
 fn main() {}

src/test/ui/const-generics/generic-sum-in-array-length.min.stderr

@@ -1,18 +1,18 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/generic-sum-in-array-length.rs:7:53
    |
 LL | fn foo<const A: usize, const B: usize>(bar: [usize; A + B]) {}
-   |                                                     ^ non-trivial anonymous constants must not depend on the parameter `A`
+   |                                                     ^ cannot perform const operation using `A`
    |
-   = help: it is currently only allowed to use either `A` or `{ A }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `A`
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/generic-sum-in-array-length.rs:7:57
    |
 LL | fn foo<const A: usize, const B: usize>(bar: [usize; A + B]) {}
-   |                                                         ^ non-trivial anonymous constants must not depend on the parameter `B`
+   |                                                         ^ cannot perform const operation using `B`
    |
-   = help: it is currently only allowed to use either `B` or `{ B }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `B`
 
 error: aborting due to 2 previous errors
 

src/test/ui/const-generics/generic-sum-in-array-length.rs

@@ -5,8 +5,8 @@
 #![cfg_attr(min, feature(min_const_generics))]
 
 fn foo<const A: usize, const B: usize>(bar: [usize; A + B]) {}
-//[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+//[min]~^ ERROR generic parameters may not be used in const operations
-//[min]~| ERROR generic parameters must not be used inside of non-trivial constant values
+//[min]~| ERROR generic parameters may not be used in const operations
 //[full]~^^^ ERROR constant expression depends on a generic parameter
 
 fn main() {}

src/test/ui/const-generics/intrinsics-type_name-as-const-argument.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/intrinsics-type_name-as-const-argument.rs:15:44
    |
 LL |     T: Trait<{std::intrinsics::type_name::<T>()}>
-   |                                            ^ non-trivial anonymous constants must not depend on the parameter `T`
+   |                                            ^ cannot perform const operation using `T`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
 error: `&'static str` is forbidden as the type of a const generic parameter
   --> $DIR/intrinsics-type_name-as-const-argument.rs:10:22

src/test/ui/const-generics/intrinsics-type_name-as-const-argument.rs

@@ -13,7 +13,7 @@ trait Trait<const S: &'static str> {}
 struct Bug<T>
 where
     T: Trait<{std::intrinsics::type_name::<T>()}>
-    //[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~^ ERROR generic parameters may not be used in const operations
     //[full]~^^ ERROR constant expression depends on a generic parameter
 {
     t: T

src/test/ui/const-generics/issue-61522-array-len-succ.min.stderr

@@ -1,18 +1,18 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-61522-array-len-succ.rs:7:45
    |
 LL | pub struct MyArray<const COUNT: usize>([u8; COUNT + 1]);
-   |                                             ^^^^^ non-trivial anonymous constants must not depend on the parameter `COUNT`
+   |                                             ^^^^^ cannot perform const operation using `COUNT`
    |
-   = help: it is currently only allowed to use either `COUNT` or `{ COUNT }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `COUNT`
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-61522-array-len-succ.rs:12:30
    |
 LL |     fn inner(&self) -> &[u8; COUNT + 1] {
-   |                              ^^^^^ non-trivial anonymous constants must not depend on the parameter `COUNT`
+   |                              ^^^^^ cannot perform const operation using `COUNT`
    |
-   = help: it is currently only allowed to use either `COUNT` or `{ COUNT }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `COUNT`
 
 error: aborting due to 2 previous errors
 

src/test/ui/const-generics/issue-61522-array-len-succ.rs

@@ -6,12 +6,12 @@
 
 pub struct MyArray<const COUNT: usize>([u8; COUNT + 1]);
 //[full]~^ ERROR constant expression depends on a generic parameter
-//[min]~^^ ERROR generic parameters must not be used
+//[min]~^^ ERROR generic parameters may not be used
 
 impl<const COUNT: usize> MyArray<COUNT> {
     fn inner(&self) -> &[u8; COUNT + 1] {
         //[full]~^ ERROR constant expression depends on a generic parameter
-        //[min]~^^ ERROR generic parameters must not be used
+        //[min]~^^ ERROR generic parameters may not be used
         &self.0
     }
 }

src/test/ui/const-generics/issue-67375.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-67375.rs:9:25
    |
 LL |     inner: [(); { [|_: &T| {}; 0].len() }],
-   |                         ^ non-trivial anonymous constants must not depend on the parameter `T`
+   |                         ^ cannot perform const operation using `T`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
 error[E0392]: parameter `T` is never used
   --> $DIR/issue-67375.rs:7:12

src/test/ui/const-generics/issue-67375.rs

@@ -7,7 +7,7 @@
 struct Bug<T> {
     //~^ ERROR parameter `T` is never used
     inner: [(); { [|_: &T| {}; 0].len() }],
-    //[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~^ ERROR generic parameters may not be used in const operations
     //[full]~^^ WARN cannot use constants which depend on generic parameters in types
     //[full]~^^^ WARN this was previously accepted by the compiler
 }

src/test/ui/const-generics/issue-67945-1.min.stderr

@@ -1,18 +1,18 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-67945-1.rs:14:16
    |
 LL |         let x: S = MaybeUninit::uninit();
-   |                ^ non-trivial anonymous constants must not depend on the parameter `S`
+   |                ^ cannot perform const operation using `S`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-67945-1.rs:17:45
    |
 LL |         let b = &*(&x as *const _ as *const S);
-   |                                             ^ non-trivial anonymous constants must not depend on the parameter `S`
+   |                                             ^ cannot perform const operation using `S`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
 error[E0392]: parameter `S` is never used
   --> $DIR/issue-67945-1.rs:11:12

src/test/ui/const-generics/issue-67945-1.rs

@@ -12,10 +12,10 @@ struct Bug<S> {
     //~^ ERROR parameter `S` is never used
     A: [(); {
         let x: S = MaybeUninit::uninit();
-        //[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+        //[min]~^ ERROR generic parameters may not be used in const operations
         //[full]~^^ ERROR mismatched types
         let b = &*(&x as *const _ as *const S);
-        //[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+        //[min]~^ ERROR generic parameters may not be used in const operations
         0
     }],
 }

src/test/ui/const-generics/issue-67945-2.min.stderr

@@ -1,18 +1,18 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-67945-2.rs:12:16
    |
 LL |         let x: S = MaybeUninit::uninit();
-   |                ^ non-trivial anonymous constants must not depend on the parameter `S`
+   |                ^ cannot perform const operation using `S`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-67945-2.rs:15:45
    |
 LL |         let b = &*(&x as *const _ as *const S);
-   |                                             ^ non-trivial anonymous constants must not depend on the parameter `S`
+   |                                             ^ cannot perform const operation using `S`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
 error[E0392]: parameter `S` is never used
   --> $DIR/issue-67945-2.rs:9:12

src/test/ui/const-generics/issue-67945-2.rs

@@ -10,10 +10,10 @@ struct Bug<S> {
     //~^ ERROR parameter `S` is never used
     A: [(); {
         let x: S = MaybeUninit::uninit();
-        //[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+        //[min]~^ ERROR generic parameters may not be used in const operations
         //[full]~^^ ERROR mismatched types
         let b = &*(&x as *const _ as *const S);
-        //[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+        //[min]~^ ERROR generic parameters may not be used in const operations
         0
     }],
 }

src/test/ui/const-generics/issues/issue-61747.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-61747.rs:8:30
    |
 LL |     fn successor() -> Const<{C + 1}> {
-   |                              ^ non-trivial anonymous constants must not depend on the parameter `C`
+   |                              ^ cannot perform const operation using `C`
    |
-   = help: it is currently only allowed to use either `C` or `{ C }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `C`
 
 error: aborting due to previous error
 

src/test/ui/const-generics/issues/issue-61747.rs

@@ -7,7 +7,7 @@ struct Const<const N: usize>;
 impl<const C: usize> Const<{C}> {
     fn successor() -> Const<{C + 1}> {
         //[full]~^ ERROR constant expression depends on a generic parameter
-        //[min]~^^ ERROR generic parameters must not be used
+        //[min]~^^ ERROR generic parameters may not be used
         Const
     }
 }

src/test/ui/const-generics/issues/issue-61935.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-61935.rs:10:23
    |
 LL |         Self:FooImpl<{N==0}>
-   |                       ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                       ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error: aborting due to previous error
 

src/test/ui/const-generics/issues/issue-61935.rs

@@ -9,7 +9,7 @@ impl<const N: usize> Foo for [(); N]
     where
         Self:FooImpl<{N==0}>
 //[full]~^ERROR constant expression depends on a generic parameter
-//[min]~^^ERROR generic parameters must not be used inside of non-trivial constant values
+//[min]~^^ERROR generic parameters may not be used in const operations
 {}
 
 trait FooImpl<const IS_ZERO: bool>{}

src/test/ui/const-generics/issues/issue-62220.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-62220.rs:8:59
    |
 LL | pub type TruncatedVector<T, const N: usize> = Vector<T, { N - 1 }>;
-   |                                                           ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                                                           ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error: aborting due to previous error
 

src/test/ui/const-generics/issues/issue-62220.rs

@@ -6,7 +6,7 @@
 pub struct Vector<T, const N: usize>([T; N]);
 
 pub type TruncatedVector<T, const N: usize> = Vector<T, { N - 1 }>;
-//[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+//[min]~^ ERROR generic parameters may not be used in const operations
 
 impl<T, const N: usize> Vector<T, { N }> {
     /// Drop the last component and return the vector with one fewer dimension.

src/test/ui/const-generics/issues/issue-62456.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-62456.rs:7:20
    |
 LL |     let _ = [0u64; N + 1];
-   |                    ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                    ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error: aborting due to previous error
 

src/test/ui/const-generics/issues/issue-62456.rs

@@ -6,7 +6,7 @@
 fn foo<const N: usize>() {
     let _ = [0u64; N + 1];
     //[full]~^ ERROR constant expression depends on a generic parameter
-    //[min]~^^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~^^ ERROR generic parameters may not be used in const operations
 }
 
 fn main() {}

src/test/ui/const-generics/issues/issue-64494.min.stderr

@@ -1,18 +1,18 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-64494.rs:16:38
    |
 LL | impl<T: Foo> MyTrait for T where Is<{T::VAL == 5}>: True {}
-   |                                      ^^^^^^ non-trivial anonymous constants must not depend on the parameter `T`
+   |                                      ^^^^^^ cannot perform const operation using `T`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-64494.rs:19:38
    |
 LL | impl<T: Foo> MyTrait for T where Is<{T::VAL == 6}>: True {}
-   |                                      ^^^^^^ non-trivial anonymous constants must not depend on the parameter `T`
+   |                                      ^^^^^^ cannot perform const operation using `T`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
 error[E0119]: conflicting implementations of trait `MyTrait`:
   --> $DIR/issue-64494.rs:19:1

src/test/ui/const-generics/issues/issue-64494.rs

@@ -15,10 +15,10 @@ impl True for Is<{true}> {}
 
 impl<T: Foo> MyTrait for T where Is<{T::VAL == 5}>: True {}
 //[full]~^ ERROR constant expression depends on a generic parameter
-//[min]~^^ ERROR generic parameters must not be used inside of non-trivial constant values
+//[min]~^^ ERROR generic parameters may not be used in const operations
 impl<T: Foo> MyTrait for T where Is<{T::VAL == 6}>: True {}
 //[full]~^ ERROR constant expression depends on a generic parameter
-//[min]~^^ ERROR generic parameters must not be used inside of non-trivial constant values
+//[min]~^^ ERROR generic parameters may not be used in const operations
 //[min]~| ERROR conflicting implementations of trait `MyTrait`
 
 fn main() {}

src/test/ui/const-generics/issues/issue-66205.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-66205.rs:8:14
    |
 LL |     fact::<{ N - 1 }>();
-   |              ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |              ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error: aborting due to previous error
 

src/test/ui/const-generics/issues/issue-66205.rs

@@ -7,7 +7,7 @@
 fn fact<const N: usize>() {
     fact::<{ N - 1 }>();
     //[full]~^ ERROR constant expression depends on a generic parameter
-    //[min]~^^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~^^ ERROR generic parameters may not be used in const operations
 }
 
 fn main() {}

src/test/ui/const-generics/issues/issue-67739.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-67739.rs:12:30
    |
 LL |         [0u8; mem::size_of::<Self::Associated>()];
-   |                              ^^^^^^^^^^^^^^^^ non-trivial anonymous constants must not depend on the parameter `Self`
+   |                              ^^^^^^^^^^^^^^^^ cannot perform const operation using `Self`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
 error: aborting due to previous error
 

src/test/ui/const-generics/issues/issue-67739.rs

@@ -11,7 +11,7 @@ pub trait Trait {
     fn associated_size(&self) -> usize {
         [0u8; mem::size_of::<Self::Associated>()];
         //[full]~^ ERROR constant expression depends on a generic parameter
-        //[min]~^^ ERROR generic parameters must not be used inside of non-trivial constant values
+        //[min]~^^ ERROR generic parameters may not be used in const operations
         0
     }
 }

src/test/ui/const-generics/issues/issue-68366.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-68366.rs:12:37
    |
 LL | impl <const N: usize> Collatz<{Some(N)}> {}
-   |                                     ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                                     ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
   --> $DIR/issue-68366.rs:12:13

src/test/ui/const-generics/issues/issue-68366.rs

@@ -11,7 +11,7 @@ struct Collatz<const N: Option<usize>>;
 
 impl <const N: usize> Collatz<{Some(N)}> {}
 //~^ ERROR the const parameter
-//[min]~^^ generic parameters must not be used inside of non-trivial constant values
+//[min]~^^ generic parameters may not be used in const operations
 
 struct Foo;
 

src/test/ui/const-generics/issues/issue-68977.min.stderr

@@ -1,18 +1,18 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-68977.rs:29:17
    |
 LL |     PhantomU8<{(INT_BITS + FRAC_BITS + 7) / 8}>;
-   |                 ^^^^^^^^ non-trivial anonymous constants must not depend on the parameter `INT_BITS`
+   |                 ^^^^^^^^ cannot perform const operation using `INT_BITS`
    |
-   = help: it is currently only allowed to use either `INT_BITS` or `{ INT_BITS }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `INT_BITS`
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-68977.rs:29:28
    |
 LL |     PhantomU8<{(INT_BITS + FRAC_BITS + 7) / 8}>;
-   |                            ^^^^^^^^^ non-trivial anonymous constants must not depend on the parameter `FRAC_BITS`
+   |                            ^^^^^^^^^ cannot perform const operation using `FRAC_BITS`
    |
-   = help: it is currently only allowed to use either `FRAC_BITS` or `{ FRAC_BITS }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `FRAC_BITS`
 
 error: aborting due to 2 previous errors
 

src/test/ui/const-generics/issues/issue-68977.rs

@@ -27,8 +27,8 @@ fxp_storage_impls! {
 
 type FxpStorageHelper<const INT_BITS: u8, const FRAC_BITS: u8> =
     PhantomU8<{(INT_BITS + FRAC_BITS + 7) / 8}>;
-    //[min]~^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~^ ERROR generic parameters may not be used in const operations
-    //[min]~| ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~| ERROR generic parameters may not be used in const operations
 
 struct Fxp<const INT_BITS: u8, const FRAC_BITS: u8>
 where

src/test/ui/const-generics/issues/issue-72787.min.stderr

@@ -1,34 +1,34 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-72787.rs:11:17
    |
 LL |     Condition<{ LHS <= RHS }>: True
-   |                 ^^^ non-trivial anonymous constants must not depend on the parameter `LHS`
+   |                 ^^^ cannot perform const operation using `LHS`
    |
-   = help: it is currently only allowed to use either `LHS` or `{ LHS }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `LHS`
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-72787.rs:11:24
    |
 LL |     Condition<{ LHS <= RHS }>: True
-   |                        ^^^ non-trivial anonymous constants must not depend on the parameter `RHS`
+   |                        ^^^ cannot perform const operation using `RHS`
    |
-   = help: it is currently only allowed to use either `RHS` or `{ RHS }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `RHS`
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-72787.rs:26:25
    |
 LL |     IsLessOrEqual<{ 8 - I }, { 8 - J }>: True,
-   |                         ^ non-trivial anonymous constants must not depend on the parameter `I`
+   |                         ^ cannot perform const operation using `I`
    |
-   = help: it is currently only allowed to use either `I` or `{ I }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `I`
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-72787.rs:26:36
    |
 LL |     IsLessOrEqual<{ 8 - I }, { 8 - J }>: True,
-   |                                    ^ non-trivial anonymous constants must not depend on the parameter `J`
+   |                                    ^ cannot perform const operation using `J`
    |
-   = help: it is currently only allowed to use either `J` or `{ J }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `J`
 
 error[E0283]: type annotations needed
   --> $DIR/issue-72787.rs:22:26

src/test/ui/const-generics/issues/issue-72787.rs

@@ -10,8 +10,8 @@ pub trait True {}
 impl<const LHS: u32, const RHS: u32> True for IsLessOrEqual<LHS, RHS> where
     Condition<{ LHS <= RHS }>: True
 //[full]~^ Error constant expression depends on a generic parameter
-//[min]~^^ Error generic parameters must not be used inside of non-trivial constant values
+//[min]~^^ Error generic parameters may not be used in const operations
-//[min]~| Error generic parameters must not be used inside of non-trivial constant values
+//[min]~| Error generic parameters may not be used in const operations
 {
 }
 impl True for Condition<true> {}
@@ -28,8 +28,8 @@ where
 //[full]~| constant expression depends on a generic parameter
 //[full]~| constant expression depends on a generic parameter
 //[full]~| constant expression depends on a generic parameter
-//[min]~^^^^^ Error generic parameters must not be used inside of non-trivial constant values
+//[min]~^^^^^ Error generic parameters may not be used in const operations
-//[min]~| Error generic parameters must not be used inside of non-trivial constant values
+//[min]~| Error generic parameters may not be used in const operations
     // Condition<{ 8 - I <= 8 - J }>: True,
 {
     fn print() {

src/test/ui/const-generics/issues/issue-72819-generic-in-const-eval.min.stderr

@@ -1,10 +1,10 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-72819-generic-in-const-eval.rs:9:17
    |
 LL | where Assert::<{N < usize::max_value() / 2}>: IsTrue,
-   |                 ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                 ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error: aborting due to previous error
 

src/test/ui/const-generics/issues/issue-72819-generic-in-const-eval.rs

@@ -8,7 +8,7 @@
 struct Arr<const N: usize>
 where Assert::<{N < usize::max_value() / 2}>: IsTrue,
 //[full]~^ ERROR constant expression depends on a generic parameter
-//[min]~^^ ERROR generic parameters must not be used inside of non-trivial constant values
+//[min]~^^ ERROR generic parameters may not be used in const operations
 {
 }
 

src/test/ui/const-generics/issues/issue-76701-ty-param-in-const.min.stderr

@@ -1,18 +1,18 @@
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-76701-ty-param-in-const.rs:6:46
    |
 LL | fn ty_param<T>() -> [u8; std::mem::size_of::<T>()] {
-   |                                              ^ non-trivial anonymous constants must not depend on the parameter `T`
+   |                                              ^ cannot perform const operation using `T`
    |
-   = note: type parameters are currently not permitted in anonymous constants
+   = note: type parameters may not be used in const expressions
 
-error: generic parameters must not be used inside of non-trivial constant values
+error: generic parameters may not be used in const operations
   --> $DIR/issue-76701-ty-param-in-const.rs:12:42
    |
 LL | fn const_param<const N: usize>() -> [u8; N + 1] {
-   |                                          ^ non-trivial anonymous constants must not depend on the parameter `N`
+   |                                          ^ cannot perform const operation using `N`
    |
-   = help: it is currently only allowed to use either `N` or `{ N }` as generic constants
+   = help: const parameters may only be used as standalone arguments, i.e. `N`
 
 error: aborting due to 2 previous errors
 

src/test/ui/const-generics/issues/issue-76701-ty-param-in-const.rs

@@ -5,13 +5,13 @@
 
 fn ty_param<T>() -> [u8; std::mem::size_of::<T>()] {
     //[full]~^ ERROR constant expression depends on a generic parameter
-    //[min]~^^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~^^ ERROR generic parameters may not be used in const operations
     todo!()
 }
 
 fn const_param<const N: usize>() -> [u8; N + 1] {
     //[full]~^ ERROR constant expression depends on a generic parameter
-    //[min]~^^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //[min]~^^ ERROR generic parameters may not be used in const operations
     todo!()
 }
 

src/test/ui/const-generics/min_const_generics/complex-expression.rs

@@ -7,19 +7,19 @@ fn ok<const M: usize>() -> [u8; M] {
 }
 
 struct Break0<const N: usize>([u8; { N + 1 }]);
-//~^ ERROR generic parameters must not be used inside of non-trivial constant values
+//~^ ERROR generic parameters may not be used in const operations
 
 struct Break1<const N: usize>([u8; { { N } }]);
-//~^ ERROR generic parameters must not be used inside of non-trivial constant values
+//~^ ERROR generic parameters may not be used in const operations
 
 fn break2<const N: usize>() {
     let _: [u8; N + 1];
-    //~^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //~^ ERROR generic parameters may not be used in const operations
 }
 
 fn break3<const N: usize>() {
     let _ = [0; N + 1];
-    //~^ ERROR generic parameters must not be used inside of non-trivial constant values
+    //~^ ERROR generic parameters may not be used in const operations
 }
 
 trait Foo {