Rollup of 7 pull requests

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -732,13 +732,15 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let tcx = self.infcx.tcx;
         // Try to find predicates on *generic params* that would allow copying `ty`
         let infcx = tcx.infer_ctxt().build();
-        if infcx
-            .type_implements_trait(
-                tcx.lang_items().clone_trait().unwrap(),
-                [tcx.erase_regions(ty)],
-                self.param_env,
-            )
-            .must_apply_modulo_regions()
+
+        if let Some(clone_trait_def) = tcx.lang_items().clone_trait()
+            && infcx
+                .type_implements_trait(
+                    clone_trait_def,
+                    [tcx.erase_regions(ty)],
+                    self.param_env,
+                )
+                .must_apply_modulo_regions()
         {
             err.span_suggestion_verbose(
                 span.shrink_to_hi(),

compiler/rustc_codegen_gcc/example/alloc_system.rs

@@ -13,17 +13,17 @@
 
 // The minimum alignment guaranteed by the architecture. This value is used to
 // add fast paths for low alignment values.
-#[cfg(all(any(target_arch = "x86",
+#[cfg(any(target_arch = "x86",
               target_arch = "arm",
               target_arch = "mips",
               target_arch = "powerpc",
-              target_arch = "powerpc64")))]
+              target_arch = "powerpc64"))]
 const MIN_ALIGN: usize = 8;
-#[cfg(all(any(target_arch = "x86_64",
+#[cfg(any(target_arch = "x86_64",
               target_arch = "aarch64",
               target_arch = "mips64",
               target_arch = "s390x",
-              target_arch = "sparc64")))]
+              target_arch = "sparc64"))]
 const MIN_ALIGN: usize = 16;
 
 pub struct System;

compiler/rustc_const_eval/src/transform/check_consts/ops.rs

@@ -376,7 +376,7 @@ impl<'tcx> NonConstOp<'tcx> for Generator {
         ccx: &ConstCx<'_, 'tcx>,
         span: Span,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
-        let msg = format!("{}s are not allowed in {}s", self.0, ccx.const_kind());
+        let msg = format!("{}s are not allowed in {}s", self.0.descr(), ccx.const_kind());
         if let hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Block) = self.0 {
             ccx.tcx.sess.create_feature_err(
                 UnallowedOpInConstContext { span, msg },

compiler/rustc_hir/src/hir.rs

@@ -1514,9 +1514,9 @@ pub enum AsyncGeneratorKind {
 impl fmt::Display for AsyncGeneratorKind {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(match self {
-            AsyncGeneratorKind::Block => "`async` block",
-            AsyncGeneratorKind::Closure => "`async` closure body",
-            AsyncGeneratorKind::Fn => "`async fn` body",
+            AsyncGeneratorKind::Block => "async block",
+            AsyncGeneratorKind::Closure => "async closure body",
+            AsyncGeneratorKind::Fn => "async fn body",
         })
     }
 }

compiler/rustc_hir_typeck/src/generator_interior/mod.rs

@@ -118,7 +118,8 @@ impl<'a, 'tcx> InteriorVisitor<'a, 'tcx> {
                 } else {
                     let note = format!(
                         "the type is part of the {} because of this {}",
-                        self.kind, yield_data.source
+                        self.kind.descr(),
+                        yield_data.source
                     );
 
                     self.fcx

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

@@ -681,25 +681,20 @@ pub trait PrettyPrinter<'tcx>:
             }
             ty::Str => p!("str"),
             ty::Generator(did, substs, movability) => {
-                // FIXME(swatinem): async constructs used to be pretty printed
-                // as `impl Future` previously due to the `from_generator` wrapping.
-                // lets special case this here for now to avoid churn in diagnostics.
-                let generator_kind = self.tcx().generator_kind(did);
-                if matches!(generator_kind, Some(hir::GeneratorKind::Async(..))) {
-                    let return_ty = substs.as_generator().return_ty();
-                    p!(write("impl Future<Output = {}>", return_ty));
-
-                    return Ok(self);
-                }
-
                 p!(write("["));
-                match movability {
-                    hir::Movability::Movable => {}
-                    hir::Movability::Static => p!("static "),
+                let generator_kind = self.tcx().generator_kind(did).unwrap();
+                let should_print_movability =
+                    self.should_print_verbose() || generator_kind == hir::GeneratorKind::Gen;
+
+                if should_print_movability {
+                    match movability {
+                        hir::Movability::Movable => {}
+                        hir::Movability::Static => p!("static "),
+                    }
                 }
 
                 if !self.should_print_verbose() {
-                    p!("generator");
+                    p!(write("{}", generator_kind));
                     // FIXME(eddyb) should use `def_span`.
                     if let Some(did) = did.as_local() {
                         let span = self.tcx().def_span(did);

compiler/rustc_span/src/analyze_source_file.rs

@@ -41,7 +41,7 @@ pub fn analyze_source_file(
 }
 
 cfg_if::cfg_if! {
-    if #[cfg(all(any(target_arch = "x86", target_arch = "x86_64")))] {
+    if #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] {
         fn analyze_source_file_dispatch(src: &str,
                                     source_file_start_pos: BytePos,
                                     lines: &mut Vec<BytePos>,

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

@@ -2673,7 +2673,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                                 let sp = self.tcx.def_span(def_id);
 
                                 // Special-case this to say "async block" instead of `[static generator]`.
-                                let kind = tcx.generator_kind(def_id).unwrap();
+                                let kind = tcx.generator_kind(def_id).unwrap().descr();
                                 err.span_note(
                                     sp,
                                     &format!("required because it's used within this {}", kind),

library/core/src/mem/mod.rs

@@ -1113,7 +1113,10 @@ impl<T> fmt::Debug for Discriminant<T> {
 /// # Stability
 ///
 /// The discriminant of an enum variant may change if the enum definition changes. A discriminant
-/// of some variant will not change between compilations with the same compiler.
+/// of some variant will not change between compilations with the same compiler. See the [Reference]
+/// for more information.
+///
+/// [Reference]: ../../reference/items/enumerations.html#custom-discriminant-values-for-fieldless-enumerations
 ///
 /// # Examples
 ///
@@ -1129,6 +1132,62 @@ impl<T> fmt::Debug for Discriminant<T> {
 /// assert_eq!(mem::discriminant(&Foo::B(1)), mem::discriminant(&Foo::B(2)));
 /// assert_ne!(mem::discriminant(&Foo::B(3)), mem::discriminant(&Foo::C(3)));
 /// ```
+///
+/// ## Accessing the numeric value of the discriminant
+///
+/// Note that it is *undefined behavior* to [`transmute`] from [`Discriminant`] to a primitive!
+///
+/// If an enum has only unit variants, then the numeric value of the discriminant can be accessed
+/// with an [`as`] cast:
+///
+/// ```
+/// enum Enum {
+///     Foo,
+///     Bar,
+///     Baz,
+/// }
+///
+/// assert_eq!(0, Enum::Foo as isize);
+/// assert_eq!(1, Enum::Bar as isize);
+/// assert_eq!(2, Enum::Baz as isize);
+/// ```
+///
+/// If an enum has opted-in to having a [primitive representation] for its discriminant,
+/// then it's possible to use pointers to read the memory location storing the discriminant.
+/// That **cannot** be done for enums using the [default representation], however, as it's
+/// undefined what layout the discriminant has and where it's stored — it might not even be
+/// stored at all!
+///
+/// [`as`]: ../../std/keyword.as.html
+/// [primitive representation]: ../../reference/type-layout.html#primitive-representations
+/// [default representation]: ../../reference/type-layout.html#the-default-representation
+/// ```
+/// #[repr(u8)]
+/// enum Enum {
+///     Unit,
+///     Tuple(bool),
+///     Struct { a: bool },
+/// }
+///
+/// impl Enum {
+///     fn discriminant(&self) -> u8 {
+///         // SAFETY: Because `Self` is marked `repr(u8)`, its layout is a `repr(C)` `union`
+///         // between `repr(C)` structs, each of which has the `u8` discriminant as its first
+///         // field, so we can read the discriminant without offsetting the pointer.
+///         unsafe { *<*const _>::from(self).cast::<u8>() }
+///     }
+/// }
+///
+/// let unit_like = Enum::Unit;
+/// let tuple_like = Enum::Tuple(true);
+/// let struct_like = Enum::Struct { a: false };
+/// assert_eq!(0, unit_like.discriminant());
+/// assert_eq!(1, tuple_like.discriminant());
+/// assert_eq!(2, struct_like.discriminant());
+///
+/// // ⚠️ This is undefined behavior. Don't do this. ⚠️
+/// // assert_eq!(0, unsafe { std::mem::transmute::<_, u8>(std::mem::discriminant(&unit_like)) });
+/// ```
 #[stable(feature = "discriminant_value", since = "1.21.0")]
 #[rustc_const_unstable(feature = "const_discriminant", issue = "69821")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "mem_discriminant")]

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

@@ -4,7 +4,7 @@ use crate::ptr;
 
 // The minimum alignment guaranteed by the architecture. This value is used to
 // add fast paths for low alignment values.
-#[cfg(all(any(
+#[cfg(any(
     target_arch = "x86",
     target_arch = "arm",
     target_arch = "mips",
@@ -16,23 +16,23 @@ use crate::ptr;
     target_arch = "hexagon",
     all(target_arch = "riscv32", not(target_os = "espidf")),
     all(target_arch = "xtensa", not(target_os = "espidf")),
-)))]
+))]
 pub const MIN_ALIGN: usize = 8;
-#[cfg(all(any(
+#[cfg(any(
     target_arch = "x86_64",
     target_arch = "aarch64",
     target_arch = "mips64",
     target_arch = "s390x",
     target_arch = "sparc64",
     target_arch = "riscv64",
     target_arch = "wasm64",
-)))]
+))]
 pub const MIN_ALIGN: usize = 16;
 // The allocator on the esp-idf platform guarantees 4 byte alignment.
-#[cfg(all(any(
+#[cfg(any(
     all(target_arch = "riscv32", target_os = "espidf"),
     all(target_arch = "xtensa", target_os = "espidf"),
-)))]
+))]
 pub const MIN_ALIGN: usize = 4;
 
 pub unsafe fn realloc_fallback(

src/bootstrap/builder.rs

@@ -644,6 +644,7 @@ impl<'a> Builder<'a> {
                 test::CrateLibrustc,
                 test::CrateRustdoc,
                 test::CrateRustdocJsonTypes,
+                test::CrateJsonDocLint,
                 test::Linkcheck,
                 test::TierCheck,
                 test::ReplacePlaceholderTest,

src/bootstrap/test.rs

@@ -90,6 +90,42 @@ fn try_run_quiet(builder: &Builder<'_>, cmd: &mut Command) -> bool {
     true
 }
 
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub struct CrateJsonDocLint {
+    host: TargetSelection,
+}
+
+impl Step for CrateJsonDocLint {
+    type Output = ();
+    const ONLY_HOSTS: bool = true;
+    const DEFAULT: bool = true;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        run.path("src/tools/jsondoclint")
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        run.builder.ensure(CrateJsonDocLint { host: run.target });
+    }
+
+    fn run(self, builder: &Builder<'_>) {
+        let bootstrap_host = builder.config.build;
+        let compiler = builder.compiler(0, bootstrap_host);
+
+        let cargo = tool::prepare_tool_cargo(
+            builder,
+            compiler,
+            Mode::ToolBootstrap,
+            bootstrap_host,
+            "test",
+            "src/tools/jsondoclint",
+            SourceType::InTree,
+            &[],
+        );
+        try_run(builder, &mut cargo.into());
+    }
+}
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub struct Linkcheck {
     host: TargetSelection,

src/librustdoc/doctest.rs

@@ -19,7 +19,7 @@ use rustc_span::edition::Edition;
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::sym;
 use rustc_span::{BytePos, FileName, Pos, Span, DUMMY_SP};
-use rustc_target::spec::TargetTriple;
+use rustc_target::spec::{Target, TargetTriple};
 use tempfile::Builder as TempFileBuilder;
 
 use std::env;
@@ -293,6 +293,16 @@ struct UnusedExterns {
     unused_extern_names: Vec<String>,
 }
 
+fn add_exe_suffix(input: String, target: &TargetTriple) -> String {
+    let exe_suffix = match target {
+        TargetTriple::TargetTriple(_) => Target::expect_builtin(target).options.exe_suffix,
+        TargetTriple::TargetJson { contents, .. } => {
+            Target::from_json(contents.parse().unwrap()).unwrap().0.options.exe_suffix
+        }
+    };
+    input + &exe_suffix
+}
+
 fn run_test(
     test: &str,
     crate_name: &str,
@@ -313,7 +323,9 @@ fn run_test(
     let (test, line_offset, supports_color) =
         make_test(test, Some(crate_name), lang_string.test_harness, opts, edition, Some(test_id));
 
-    let output_file = outdir.path().join("rust_out");
+    // Make sure we emit well-formed executable names for our target.
+    let rust_out = add_exe_suffix("rust_out".to_owned(), &target);
+    let output_file = outdir.path().join(rust_out);
 
     let rustc_binary = rustdoc_options
         .test_builder