Rollup of 10 pull requests

compiler/rustc_error_codes/src/error_codes.rs

@@ -103,7 +103,6 @@ E0198: include_str!("./error_codes/E0198.md"),
 E0199: include_str!("./error_codes/E0199.md"),
 E0200: include_str!("./error_codes/E0200.md"),
 E0201: include_str!("./error_codes/E0201.md"),
-E0202: include_str!("./error_codes/E0202.md"),
 E0203: include_str!("./error_codes/E0203.md"),
 E0204: include_str!("./error_codes/E0204.md"),
 E0205: include_str!("./error_codes/E0205.md"),

compiler/rustc_feature/src/active.rs

@@ -641,6 +641,9 @@ declare_features! (
     /// Allows `pub` on `macro_rules` items.
     (active, pub_macro_rules, "1.52.0", Some(78855), None),
 
+    /// Allows associated types in inherent impls.
+    (active, inherent_associated_types, "1.52.0", Some(8995), None),
+
     // -------------------------------------------------------------------------
     // feature-group-end: actual feature gates
     // -------------------------------------------------------------------------
@@ -666,6 +669,7 @@ pub const INCOMPLETE_FEATURES: &[Symbol] = &[
     sym::unsized_locals,
     sym::capture_disjoint_fields,
     sym::const_generics_defaults,
+    sym::inherent_associated_types,
 ];
 
 /// Some features are not allowed to be used together at the same time, if

compiler/rustc_interface/src/tests.rs

@@ -557,8 +557,9 @@ fn test_debugging_options_tracking_hash() {
     tracked!(function_sections, Some(false));
     tracked!(human_readable_cgu_names, true);
     tracked!(inline_in_all_cgus, Some(true));
-    tracked!(inline_mir_threshold, 123);
-    tracked!(inline_mir_hint_threshold, 123);
+    tracked!(inline_mir, Some(true));
+    tracked!(inline_mir_threshold, Some(123));
+    tracked!(inline_mir_hint_threshold, Some(123));
     tracked!(insert_sideeffect, true);
     tracked!(instrument_coverage, true);
     tracked!(instrument_mcount, true);

compiler/rustc_mir/src/transform/inline.rs

@@ -37,21 +37,27 @@ struct CallSite<'tcx> {
     source_info: SourceInfo,
 }
 
+/// Returns true if MIR inlining is enabled in the current compilation session.
+crate fn is_enabled(tcx: TyCtxt<'_>) -> bool {
+    if tcx.sess.opts.debugging_opts.instrument_coverage {
+        // Since `Inline` happens after `InstrumentCoverage`, the function-specific coverage
+        // counters can be invalidated, such as by merging coverage counter statements from
+        // a pre-inlined function into a different function. This kind of change is invalid,
+        // so inlining must be skipped. Note: This check is performed here so inlining can
+        // be disabled without preventing other optimizations (regardless of `mir_opt_level`).
+        return false;
+    }
+
+    if let Some(enabled) = tcx.sess.opts.debugging_opts.inline_mir {
+        return enabled;
+    }
+
+    tcx.sess.opts.debugging_opts.mir_opt_level >= 2
+}
+
 impl<'tcx> MirPass<'tcx> for Inline {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        // If you change this optimization level, also change the level in
-        // `mir_drops_elaborated_and_const_checked` for the call to `mir_inliner_callees`.
-        // Otherwise you will get an ICE about stolen MIR.
-        if tcx.sess.opts.debugging_opts.mir_opt_level < 2 {
-            return;
-        }
-
-        if tcx.sess.opts.debugging_opts.instrument_coverage {
-            // Since `Inline` happens after `InstrumentCoverage`, the function-specific coverage
-            // counters can be invalidated, such as by merging coverage counter statements from
-            // a pre-inlined function into a different function. This kind of change is invalid,
-            // so inlining must be skipped. Note: This check is performed here so inlining can
-            // be disabled without preventing other optimizations (regardless of `mir_opt_level`).
+        if !is_enabled(tcx) {
             return;
         }
 
@@ -343,9 +349,9 @@ impl Inliner<'tcx> {
         let tcx = self.tcx;
 
         let mut threshold = if callee_attrs.requests_inline() {
-            self.tcx.sess.opts.debugging_opts.inline_mir_hint_threshold
+            self.tcx.sess.opts.debugging_opts.inline_mir_hint_threshold.unwrap_or(100)
         } else {
-            self.tcx.sess.opts.debugging_opts.inline_mir_threshold
+            self.tcx.sess.opts.debugging_opts.inline_mir_threshold.unwrap_or(50)
         };
 
         // Give a bonus functions with a small number of blocks,

compiler/rustc_mir/src/transform/mod.rs

@@ -430,8 +430,7 @@ fn mir_drops_elaborated_and_const_checked<'tcx>(
         let def = ty::WithOptConstParam::unknown(did);
 
         // Do not compute the mir call graph without said call graph actually being used.
-        // Keep this in sync with the mir inliner's optimization level.
-        if tcx.sess.opts.debugging_opts.mir_opt_level >= 2 {
+        if inline::is_enabled(tcx) {
             let _ = tcx.mir_inliner_callees(ty::InstanceDef::Item(def));
         }
     }

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -662,7 +662,7 @@ impl<'a> Parser<'a> {
                     let x = self.parse_seq_to_before_end(
                         &token::Gt,
                         SeqSep::trailing_allowed(token::Comma),
-                        |p| p.parse_ty(),
+                        |p| p.parse_generic_arg(),
                     );
                     match x {
                         Ok((_, _, false)) => {

compiler/rustc_parse/src/parser/path.rs

@@ -545,7 +545,7 @@ impl<'a> Parser<'a> {
 
     /// Parse a generic argument in a path segment.
     /// This does not include constraints, e.g., `Item = u8`, which is handled in `parse_angle_arg`.
-    fn parse_generic_arg(&mut self) -> PResult<'a, Option<GenericArg>> {
+    pub(super) fn parse_generic_arg(&mut self) -> PResult<'a, Option<GenericArg>> {
         let start = self.token.span;
         let arg = if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
             // Parse lifetime argument.

compiler/rustc_parse/src/parser/ty.rs

@@ -360,12 +360,20 @@ impl<'a> Parser<'a> {
             }
             Err(err) => return Err(err),
         };
+
         let ty = if self.eat(&token::Semi) {
-            TyKind::Array(elt_ty, self.parse_anon_const_expr()?)
+            let mut length = self.parse_anon_const_expr()?;
+            if let Err(e) = self.expect(&token::CloseDelim(token::Bracket)) {
+                // Try to recover from `X<Y, ...>` when `X::<Y, ...>` works
+                self.check_mistyped_turbofish_with_multiple_type_params(e, &mut length.value)?;
+                self.expect(&token::CloseDelim(token::Bracket))?;
+            }
+            TyKind::Array(elt_ty, length)
         } else {
+            self.expect(&token::CloseDelim(token::Bracket))?;
             TyKind::Slice(elt_ty)
         };
-        self.expect(&token::CloseDelim(token::Bracket))?;
+
         Ok(ty)
     }
 

compiler/rustc_session/src/options.rs

@@ -957,9 +957,11 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         (default: no)"),
     incremental_verify_ich: bool = (false, parse_bool, [UNTRACKED],
         "verify incr. comp. hashes of green query instances (default: no)"),
-    inline_mir_threshold: usize = (50, parse_uint, [TRACKED],
+    inline_mir: Option<bool> = (None, parse_opt_bool, [TRACKED],
+        "enable MIR inlining (default: no)"),
+    inline_mir_threshold: Option<usize> = (None, parse_opt_uint, [TRACKED],
         "a default MIR inlining threshold (default: 50)"),
-    inline_mir_hint_threshold: usize = (100, parse_uint, [TRACKED],
+    inline_mir_hint_threshold: Option<usize> = (None, parse_opt_uint, [TRACKED],
         "inlining threshold for functions with inline hint (default: 100)"),
     inline_in_all_cgus: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "control whether `#[inline]` functions are in all CGUs"),

compiler/rustc_span/src/symbol.rs

@@ -634,6 +634,7 @@ symbols! {
         index_mut,
         infer_outlives_requirements,
         infer_static_outlives_requirements,
+        inherent_associated_types,
         inlateout,
         inline,
         inline_const,

compiler/rustc_trait_selection/src/traits/auto_trait.rs

@@ -77,7 +77,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
         ty: Ty<'tcx>,
         orig_env: ty::ParamEnv<'tcx>,
         trait_did: DefId,
-        mut auto_trait_callback: impl FnMut(&InferCtxt<'_, 'tcx>, AutoTraitInfo<'tcx>) -> A,
+        mut auto_trait_callback: impl FnMut(AutoTraitInfo<'tcx>) -> A,
     ) -> AutoTraitResult<A> {
         let tcx = self.tcx;
 
@@ -211,7 +211,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
 
             let info = AutoTraitInfo { full_user_env, region_data, vid_to_region };
 
-            AutoTraitResult::PositiveImpl(auto_trait_callback(&infcx, info))
+            AutoTraitResult::PositiveImpl(auto_trait_callback(info))
         })
     }
 }

compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs

@@ -11,7 +11,7 @@ use rustc_hir::lang_items::LangItem;
 use rustc_hir::{ExprKind, ItemKind, Node};
 use rustc_infer::infer;
 use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty::{self, Ty};
+use rustc_middle::ty::{self, Binder, Ty};
 use rustc_span::symbol::kw;
 
 use std::iter;
@@ -487,6 +487,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let found = self.resolve_vars_with_obligations(found);
         if let hir::FnRetTy::Return(ty) = fn_decl.output {
             let ty = AstConv::ast_ty_to_ty(self, ty);
+            let ty = self.tcx.erase_late_bound_regions(Binder::bind(ty));
             let ty = self.normalize_associated_types_in(expr.span, ty);
             if self.can_coerce(found, ty) {
                 err.multipart_suggestion(

compiler/rustc_typeck/src/collect/type_of.rs

@@ -1,4 +1,3 @@
-use crate::errors::AssocTypeOnInherentImpl;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{Applicability, ErrorReported, StashKey};
 use rustc_hir as hir;
@@ -294,7 +293,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
             }
             ImplItemKind::TyAlias(ref ty) => {
                 if tcx.impl_trait_ref(tcx.hir().get_parent_did(hir_id).to_def_id()).is_none() {
-                    report_assoc_ty_on_inherent_impl(tcx, item.span);
+                    check_feature_inherent_assoc_ty(tcx, item.span);
                 }
 
                 icx.to_ty(ty)
@@ -746,6 +745,16 @@ fn infer_placeholder_type(
     })
 }
 
-fn report_assoc_ty_on_inherent_impl(tcx: TyCtxt<'_>, span: Span) {
-    tcx.sess.emit_err(AssocTypeOnInherentImpl { span });
+fn check_feature_inherent_assoc_ty(tcx: TyCtxt<'_>, span: Span) {
+    if !tcx.features().inherent_associated_types {
+        use rustc_session::parse::feature_err;
+        use rustc_span::symbol::sym;
+        feature_err(
+            &tcx.sess.parse_sess,
+            sym::inherent_associated_types,
+            span,
+            "inherent associated types are unstable",
+        )
+        .emit();
+    }
 }

compiler/rustc_typeck/src/errors.rs

@@ -82,13 +82,6 @@ pub struct CopyImplOnTypeWithDtor {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
-#[error = "E0202"]
-pub struct AssocTypeOnInherentImpl {
-    #[message = "associated types are not yet supported in inherent impls (see #8995)"]
-    pub span: Span,
-}
-
 #[derive(SessionDiagnostic)]
 #[error = "E0203"]
 pub struct MultipleRelaxedDefaultBounds {

library/alloc/src/lib.rs

@@ -104,6 +104,11 @@
 #![feature(fundamental)]
 #![feature(inplace_iteration)]
 #![feature(int_bits_const)]
+// Technically, this is a bug in rustdoc: rustdoc sees the documentation on `#[lang = slice_alloc]`
+// blocks is for `&[T]`, which also has documentation using this feature in `core`, and gets mad
+// that the feature-gate isn't enabled. Ideally, it wouldn't check for the feature gate for docs
+// from other crates, but since this can only appear for lang items, it doesn't seem worth fixing.
+#![feature(intra_doc_pointers)]
 #![feature(lang_items)]
 #![feature(layout_for_ptr)]
 #![feature(maybe_uninit_ref)]

library/alloc/src/slice.rs

@@ -1,6 +1,6 @@
 //! A dynamically-sized view into a contiguous sequence, `[T]`.
 //!
-//! *[See also the slice primitive type](../../std/primitive.slice.html).*
+//! *[See also the slice primitive type](slice).*
 //!
 //! Slices are a view into a block of memory represented as a pointer and a
 //! length.
@@ -71,12 +71,12 @@
 //!   [`.chunks`], [`.windows`] and more.
 //!
 //! [`Hash`]: core::hash::Hash
-//! [`.iter`]: ../../std/primitive.slice.html#method.iter
-//! [`.iter_mut`]: ../../std/primitive.slice.html#method.iter_mut
-//! [`.split`]: ../../std/primitive.slice.html#method.split
-//! [`.splitn`]: ../../std/primitive.slice.html#method.splitn
-//! [`.chunks`]: ../../std/primitive.slice.html#method.chunks
-//! [`.windows`]: ../../std/primitive.slice.html#method.windows
+//! [`.iter`]: slice::iter
+//! [`.iter_mut`]: slice::iter_mut
+//! [`.split`]: slice::split
+//! [`.splitn`]: slice::splitn
+//! [`.chunks`]: slice::chunks
+//! [`.windows`]: slice::windows
 #![stable(feature = "rust1", since = "1.0.0")]
 // Many of the usings in this module are only used in the test configuration.
 // It's cleaner to just turn off the unused_imports warning than to fix them.
@@ -673,7 +673,7 @@ impl [u8] {
 // Extension traits for slices over specific kinds of data
 ////////////////////////////////////////////////////////////////////////////////
 
-/// Helper trait for [`[T]::concat`](../../std/primitive.slice.html#method.concat).
+/// Helper trait for [`[T]::concat`](slice::concat).
 ///
 /// Note: the `Item` type parameter is not used in this trait,
 /// but it allows impls to be more generic.
@@ -708,19 +708,19 @@ pub trait Concat<Item: ?Sized> {
     /// The resulting type after concatenation
     type Output;
 
-    /// Implementation of [`[T]::concat`](../../std/primitive.slice.html#method.concat)
+    /// Implementation of [`[T]::concat`](slice::concat)
     #[unstable(feature = "slice_concat_trait", issue = "27747")]
     fn concat(slice: &Self) -> Self::Output;
 }
 
-/// Helper trait for [`[T]::join`](../../std/primitive.slice.html#method.join)
+/// Helper trait for [`[T]::join`](slice::join)
 #[unstable(feature = "slice_concat_trait", issue = "27747")]
 pub trait Join<Separator> {
     #[unstable(feature = "slice_concat_trait", issue = "27747")]
     /// The resulting type after concatenation
     type Output;
 
-    /// Implementation of [`[T]::join`](../../std/primitive.slice.html#method.join)
+    /// Implementation of [`[T]::join`](slice::join)
     #[unstable(feature = "slice_concat_trait", issue = "27747")]
     fn join(slice: &Self, sep: Separator) -> Self::Output;
 }

library/alloc/src/str.rs

@@ -1,6 +1,6 @@
 //! Unicode string slices.
 //!
-//! *[See also the `str` primitive type](../../std/primitive.str.html).*
+//! *[See also the `str` primitive type](str).*
 //!
 //! The `&str` type is one of the two main string types, the other being `String`.
 //! Unlike its `String` counterpart, its contents are borrowed.

library/alloc/src/string.rs

@@ -495,7 +495,7 @@ impl String {
     /// `from_utf8_lossy()` will replace any invalid UTF-8 sequences with
     /// [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD], which looks like this: �
     ///
-    /// [byteslice]: ../../std/primitive.slice.html
+    /// [byteslice]: prim@slice
     /// [U+FFFD]: core::char::REPLACEMENT_CHARACTER
     ///
     /// If you are sure that the byte slice is valid UTF-8, and you don't want

library/alloc/src/vec/mod.rs

@@ -216,7 +216,7 @@ mod spec_extend;
 /// # Slicing
 ///
 /// A `Vec` can be mutable. Slices, on the other hand, are read-only objects.
-/// To get a [slice], use [`&`]. Example:
+/// To get a [slice][prim@slice], use [`&`]. Example:
 ///
 /// ```
 /// fn read_slice(slice: &[usize]) {
@@ -369,8 +369,6 @@ mod spec_extend;
 /// [`reserve`]: Vec::reserve
 /// [`MaybeUninit`]: core::mem::MaybeUninit
 /// [owned slice]: Box
-/// [slice]: ../../std/primitive.slice.html
-/// [`&`]: ../../std/primitive.reference.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "vec_type")]
 pub struct Vec<T, #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global> {
@@ -2517,7 +2515,7 @@ impl<T, A: Allocator> Vec<T, A> {
 /// This implementation is specialized for slice iterators, where it uses [`copy_from_slice`] to
 /// append the entire slice at once.
 ///
-/// [`copy_from_slice`]: ../../std/primitive.slice.html#method.copy_from_slice
+/// [`copy_from_slice`]: slice::copy_from_slice
 #[stable(feature = "extend_ref", since = "1.2.0")]
 impl<'a, T: Copy + 'a, A: Allocator + 'a> Extend<&'a T> for Vec<T, A> {
     fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) {

library/core/src/alloc/layout.rs

@@ -164,7 +164,6 @@ impl Layout {
     ///       [`Layout::for_value`] on a reference to an extern type tail.
     ///     - otherwise, it is conservatively not allowed to call this function.
     ///
-    /// [slice]: ../../std/primitive.slice.html
     /// [trait object]: ../../book/ch17-02-trait-objects.html
     /// [extern type]: ../../unstable-book/language-features/extern-types.html
     #[unstable(feature = "layout_for_ptr", issue = "69835")]

library/core/src/array/iter.rs

@@ -9,8 +9,6 @@ use crate::{
 };
 
 /// A by-value [array] iterator.
-///
-/// [array]: ../../std/primitive.array.html
 #[stable(feature = "array_value_iter", since = "1.51.0")]
 pub struct IntoIter<T, const N: usize> {
     /// This is the array we are iterating over.