Rollup of 8 pull requests

compiler/rustc_borrowck/src/type_check/free_region_relations.rs

@@ -256,7 +256,6 @@ impl UniversalRegionRelationsBuilder<'cx, 'tcx> {
                 debug!("build: input_or_output={:?}", ty);
                 // We add implied bounds from both the unnormalized and normalized ty
                 // See issue #87748
-                let constraints_implied_1 = self.add_implied_bounds(ty);
                 let TypeOpOutput { output: norm_ty, constraints: constraints1, .. } = self
                     .param_env
                     .and(type_op::normalize::Normalize::new(ty))
@@ -284,10 +283,9 @@ impl UniversalRegionRelationsBuilder<'cx, 'tcx> {
                 // }
                 // ```
                 // Both &Self::Bar and &() are WF
-                let constraints_implied_2 =
-                    if ty != norm_ty { self.add_implied_bounds(norm_ty) } else { None };
+                let constraints_implied = self.add_implied_bounds(norm_ty);
                 normalized_inputs_and_output.push(norm_ty);
-                constraints1.into_iter().chain(constraints_implied_1).chain(constraints_implied_2)
+                constraints1.into_iter().chain(constraints_implied)
             })
             .collect();
 

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -394,10 +394,12 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             sym::transmute => {
                 self.copy_op_transmute(&args[0], dest)?;
             }
-            sym::assert_inhabited => {
+            sym::assert_inhabited | sym::assert_zero_valid | sym::assert_uninit_valid => {
                 let ty = instance.substs.type_at(0);
                 let layout = self.layout_of(ty)?;
 
+                // For *all* intrinsics we first check `is_uninhabited` to give a more specific
+                // error message.
                 if layout.abi.is_uninhabited() {
                     // The run-time intrinsic panics just to get a good backtrace; here we abort
                     // since there is no problem showing a backtrace even for aborts.
@@ -409,6 +411,28 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         ),
                     )?;
                 }
+                if intrinsic_name == sym::assert_zero_valid
+                    && !layout.might_permit_raw_init(self, /*zero:*/ true)
+                {
+                    M::abort(
+                        self,
+                        format!(
+                            "aborted execution: attempted to zero-initialize type `{}`, which is invalid",
+                            ty
+                        ),
+                    )?;
+                }
+                if intrinsic_name == sym::assert_uninit_valid
+                    && !layout.might_permit_raw_init(self, /*zero:*/ false)
+                {
+                    M::abort(
+                        self,
+                        format!(
+                            "aborted execution: attempted to leave type `{}` uninitialized, which is invalid",
+                            ty
+                        ),
+                    )?;
+                }
             }
             sym::simd_insert => {
                 let index = u64::from(self.read_scalar(&args[1])?.to_u32()?);

compiler/rustc_const_eval/src/transform/mod.rs

@@ -1,5 +1,3 @@
 pub mod check_consts;
 pub mod promote_consts;
 pub mod validate;
-
-pub use rustc_middle::mir::MirPass;

compiler/rustc_const_eval/src/transform/promote_consts.rs

@@ -27,7 +27,6 @@ use std::cell::Cell;
 use std::{cmp, iter, mem};
 
 use crate::transform::check_consts::{qualifs, ConstCx};
-use crate::transform::MirPass;
 
 /// A `MirPass` for promotion.
 ///

compiler/rustc_const_eval/src/transform/validate.rs

@@ -1,14 +1,13 @@
 //! Validates the MIR to ensure that invariants are upheld.
 
-use super::MirPass;
 use rustc_index::bit_set::BitSet;
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::mir::interpret::Scalar;
 use rustc_middle::mir::traversal;
 use rustc_middle::mir::visit::{PlaceContext, Visitor};
 use rustc_middle::mir::{
-    AggregateKind, BasicBlock, Body, BorrowKind, Local, Location, MirPhase, Operand, PlaceElem,
-    PlaceRef, ProjectionElem, Rvalue, SourceScope, Statement, StatementKind, Terminator,
+    AggregateKind, BasicBlock, Body, BorrowKind, Local, Location, MirPass, MirPhase, Operand,
+    PlaceElem, PlaceRef, ProjectionElem, Rvalue, SourceScope, Statement, StatementKind, Terminator,
     TerminatorKind, START_BLOCK,
 };
 use rustc_middle::ty::fold::BottomUpFolder;

compiler/rustc_errors/src/emitter.rs

@@ -214,7 +214,7 @@ pub trait Emitter {
 
     /// Formats the substitutions of the primary_span
     ///
-    /// The are a lot of conditions to this method, but in short:
+    /// There are a lot of conditions to this method, but in short:
     ///
     /// * If the current `Diagnostic` has only one visible `CodeSuggestion`,
     ///   we format the `help` suggestion depending on the content of the
@@ -736,7 +736,9 @@ impl EmitterWriter {
 
         let line_offset = buffer.num_lines();
 
-        let left = margin.left(source_string.len()); // Left trim
+        // Left trim
+        let left = margin.left(source_string.len());
+
         // Account for unicode characters of width !=0 that were removed.
         let left = source_string
             .chars()
@@ -1623,18 +1625,27 @@ impl EmitterWriter {
             suggestions.iter().take(MAX_SUGGESTIONS)
         {
             notice_capitalization |= only_capitalization;
-            // Only show underline if the suggestion spans a single line and doesn't cover the
-            // entirety of the code output. If you have multiple replacements in the same line
-            // of code, show the underline.
-            let show_underline = !(parts.len() == 1 && parts[0].snippet.trim() == complete.trim())
-                && complete.lines().count() == 1;
 
             let has_deletion = parts.iter().any(|p| p.is_deletion());
             let is_multiline = complete.lines().count() > 1;
 
-            let show_diff = has_deletion && !is_multiline;
+            enum DisplaySuggestion {
+                Underline,
+                Diff,
+                None,
+            }
+
+            let show_code_change = if has_deletion && !is_multiline {
+                DisplaySuggestion::Diff
+            } else if (parts.len() != 1 || parts[0].snippet.trim() != complete.trim())
+                && !is_multiline
+            {
+                DisplaySuggestion::Underline
+            } else {
+                DisplaySuggestion::None
+            };
 
-            if show_diff {
+            if let DisplaySuggestion::Diff = show_code_change {
                 row_num += 1;
             }
 
@@ -1657,7 +1668,7 @@ impl EmitterWriter {
                     &self.maybe_anonymized(line_start + line_pos),
                     Style::LineNumber,
                 );
-                if show_diff {
+                if let DisplaySuggestion::Diff = show_code_change {
                     // Add the line number for both addition and removal to drive the point home.
                     //
                     // N - fn foo<A: T>(bar: A) {
@@ -1727,7 +1738,7 @@ impl EmitterWriter {
             let mut offsets: Vec<(usize, isize)> = Vec::new();
             // Only show an underline in the suggestions if the suggestion is not the
             // entirety of the code being shown and the displayed code is not multiline.
-            if show_underline {
+            if let DisplaySuggestion::Diff | DisplaySuggestion::Underline = show_code_change {
                 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
                 for part in parts {
                     let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
@@ -1755,7 +1766,7 @@ impl EmitterWriter {
                     assert!(underline_start >= 0 && underline_end >= 0);
                     let padding: usize = max_line_num_len + 3;
                     for p in underline_start..underline_end {
-                        if !show_diff {
+                        if let DisplaySuggestion::Underline = show_code_change {
                             // If this is a replacement, underline with `^`, if this is an addition
                             // underline with `+`.
                             buffer.putc(
@@ -1766,7 +1777,7 @@ impl EmitterWriter {
                             );
                         }
                     }
-                    if show_diff {
+                    if let DisplaySuggestion::Diff = show_code_change {
                         // Colorize removal with red in diff format.
                         buffer.set_style_range(
                             row_num - 2,
@@ -1797,7 +1808,7 @@ impl EmitterWriter {
             // if we elided some lines, add an ellipsis
             if lines.next().is_some() {
                 buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber);
-            } else if !show_underline {
+            } else if let DisplaySuggestion::None = show_code_change {
                 draw_col_separator_no_space(&mut buffer, row_num, max_line_num_len + 1);
                 row_num += 1;
             }
@@ -2083,7 +2094,7 @@ const OUTPUT_REPLACEMENTS: &[(char, &str)] = &[
     ('\t', "    "),   // We do our own tab replacement
     ('\u{200D}', ""), // Replace ZWJ with nothing for consistent terminal output of grapheme clusters.
     ('\u{202A}', ""), // The following unicode text flow control characters are inconsistently
-    ('\u{202B}', ""), // supported accross CLIs and can cause confusion due to the bytes on disk
+    ('\u{202B}', ""), // supported across CLIs and can cause confusion due to the bytes on disk
     ('\u{202D}', ""), // not corresponding to the visible source code, so we replace them always.
     ('\u{202E}', ""),
     ('\u{2066}', ""),

compiler/rustc_mir_transform/src/lib.rs

@@ -27,7 +27,7 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_index::vec::IndexVec;
 use rustc_middle::mir::visit::Visitor as _;
-use rustc_middle::mir::{dump_mir, traversal, Body, ConstQualifs, MirPhase, Promoted};
+use rustc_middle::mir::{dump_mir, traversal, Body, ConstQualifs, MirPass, MirPhase, Promoted};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, TyCtxt, TypeFoldable};
 use rustc_span::{Span, Symbol};
@@ -78,7 +78,6 @@ mod unreachable_prop;
 use rustc_const_eval::transform::check_consts;
 use rustc_const_eval::transform::promote_consts;
 use rustc_const_eval::transform::validate;
-pub use rustc_const_eval::transform::MirPass;
 use rustc_mir_dataflow::rustc_peek;
 
 pub fn provide(providers: &mut Providers) {

compiler/rustc_typeck/src/check/compare_method.rs

@@ -264,14 +264,9 @@ fn compare_predicate_entailment<'tcx>(
         // First liberate late bound regions and subst placeholders
         let trait_sig = tcx.liberate_late_bound_regions(impl_m.def_id, tcx.fn_sig(trait_m.def_id));
         let trait_sig = trait_sig.subst(tcx, trait_to_placeholder_substs);
-        // Next, add all inputs and output as well-formed tys. Importantly,
-        // we have to do this before normalization, since the normalized ty may
-        // not contain the input parameters. See issue #87748.
-        wf_tys.extend(trait_sig.inputs_and_output.iter());
         let trait_sig =
             inh.normalize_associated_types_in(impl_m_span, impl_m_hir_id, param_env, trait_sig);
-        // Also add the resulting inputs and output as well-formed.
-        // This probably isn't strictly necessary.
+        // Add the resulting inputs and output as well-formed.
         wf_tys.extend(trait_sig.inputs_and_output.iter());
         let trait_fty = tcx.mk_fn_ptr(ty::Binder::dummy(trait_sig));
 

compiler/rustc_typeck/src/check/mod.rs

@@ -391,7 +391,6 @@ fn typeck_with_fallback<'tcx>(
             let mut wf_tys = FxHashSet::default();
             // Compute the fty from point of view of inside the fn.
             let fn_sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), fn_sig);
-            wf_tys.extend(fn_sig.inputs_and_output.iter());
             let fn_sig = inh.normalize_associated_types_in(
                 body.value.span,
                 body_id.hir_id,

compiler/rustc_typeck/src/check/wfcheck.rs

@@ -1334,11 +1334,6 @@ fn check_fn_or_method<'fcx, 'tcx>(
 ) {
     let sig = fcx.tcx.liberate_late_bound_regions(def_id, sig);
 
-    // Unnormalized types in signature are WF too
-    implied_bounds.extend(sig.inputs());
-    // FIXME(#27579) return types should not be implied bounds
-    implied_bounds.insert(sig.output());
-
     // Normalize the input and output types one at a time, using a different
     // `WellFormedLoc` for each. We cannot call `normalize_associated_types`
     // on the entire `FnSig`, since this would use the same `WellFormedLoc`

library/core/src/intrinsics.rs

@@ -860,12 +860,14 @@ extern "rust-intrinsic" {
     /// zero-initialization: This will statically either panic, or do nothing.
     ///
     /// This intrinsic does not have a stable counterpart.
+    #[rustc_const_unstable(feature = "const_assert_type2", issue = "none")]
     pub fn assert_zero_valid<T>();
 
     /// A guard for unsafe functions that cannot ever be executed if `T` has invalid
     /// bit patterns: This will statically either panic, or do nothing.
     ///
     /// This intrinsic does not have a stable counterpart.
+    #[rustc_const_unstable(feature = "const_assert_type2", issue = "none")]
     pub fn assert_uninit_valid<T>();
 
     /// Gets a reference to a static `Location` indicating where it was called.

library/core/src/iter/traits/iterator.rs

@@ -1023,6 +1023,7 @@ pub trait Iterator {
     /// assert_eq!(iter.next(), None);
     /// ```
     #[inline]
+    #[doc(alias = "drop_while")]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>
     where

src/test/debuginfo/rc_arc.rs

@@ -1,4 +1,4 @@
-// pretty-printers are not loaded
+// ignore-windows-gnu: pretty-printers are not loaded
 // compile-flags:-g
 
 // min-gdb-version: 8.1

src/test/ui/consts/assert-type-intrinsics.rs

@@ -0,0 +1,22 @@
+// error-pattern: any use of this value will cause an error
+
+#![feature(never_type)]
+#![feature(const_maybe_uninit_assume_init, const_assert_type2)]
+#![feature(core_intrinsics)]
+
+use std::intrinsics;
+
+#[allow(invalid_value)]
+fn main() {
+    use std::mem::MaybeUninit;
+
+    const _BAD1: () = unsafe {
+        MaybeUninit::<!>::uninit().assume_init();
+    };
+    const _BAD2: () = unsafe {
+        intrinsics::assert_uninit_valid::<bool>();
+    };
+    const _BAD3: () = unsafe {
+        intrinsics::assert_zero_valid::<&'static i32>();
+    };
+}

src/test/ui/consts/assert-type-intrinsics.stderr

@@ -0,0 +1,39 @@
+error: any use of this value will cause an error
+  --> $DIR/assert-type-intrinsics.rs:14:9
+   |
+LL | /     const _BAD1: () = unsafe {
+LL | |         MaybeUninit::<!>::uninit().assume_init();
+   | |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to instantiate uninhabited type `!`
+LL | |     };
+   | |______-
+   |
+   = note: `#[deny(const_err)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+
+error: any use of this value will cause an error
+  --> $DIR/assert-type-intrinsics.rs:17:9
+   |
+LL | /     const _BAD2: () = unsafe {
+LL | |         intrinsics::assert_uninit_valid::<bool>();
+   | |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to leave type `bool` uninitialized, which is invalid
+LL | |     };
+   | |______-
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+
+error: any use of this value will cause an error
+  --> $DIR/assert-type-intrinsics.rs:20:9
+   |
+LL | /     const _BAD3: () = unsafe {
+LL | |         intrinsics::assert_zero_valid::<&'static i32>();
+   | |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to zero-initialize type `&i32`, which is invalid
+LL | |     };
+   | |______-
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+
+error: aborting due to 3 previous errors
+

src/test/ui/fn/implied-bounds-unnorm-associated-type.nll.stderr

@@ -0,0 +1,14 @@
+error: lifetime may not live long enough
+  --> $DIR/implied-bounds-unnorm-associated-type.rs:14:5
+   |
+LL | fn f<'a, 'b>(s: &'b str, _: <&'a &'b () as Trait>::Type) -> &'a str {
+   |      --  -- lifetime `'b` defined here
+   |      |
+   |      lifetime `'a` defined here
+LL |     s
+   |     ^ returning this value requires that `'b` must outlive `'a`
+   |
+   = help: consider adding the following bound: `'b: 'a`
+
+error: aborting due to previous error
+