Auto merge of rust-lang#124934 - matthiaskrgr:rollup-eqor0ot, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - rust-lang#124893 (Make a minimal amount of region APIs public)
 - rust-lang#124919 (Add `ErrorGuaranteed` to `Recovered::Yes` and use it more.)
 - rust-lang#124923 (interpret/miri: better errors on failing offset_from)
 - rust-lang#124924 (chore: remove repetitive words)
 - rust-lang#124926 (Make `#![feature]` suggestion MaybeIncorrect)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_ast/src/ast.rs

@@ -1422,7 +1422,7 @@ pub enum ExprKind {
     /// of `if` / `while` expressions. (e.g., `if let 0 = x { .. }`).
     ///
     /// `Span` represents the whole `let pat = expr` statement.
-    Let(P<Pat>, P<Expr>, Span, Option<ErrorGuaranteed>),
+    Let(P<Pat>, P<Expr>, Span, Recovered),
     /// An `if` block, with an optional `else` block.
     ///
     /// `if expr { block } else { expr }`
@@ -2881,17 +2881,20 @@ pub struct FieldDef {
     pub is_placeholder: bool,
 }
 
+/// Was parsing recovery performed?
+#[derive(Copy, Clone, Debug, Encodable, Decodable, HashStable_Generic)]
+pub enum Recovered {
+    No,
+    Yes(ErrorGuaranteed),
+}
+
 /// Fields and constructor ids of enum variants and structs.
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub enum VariantData {
     /// Struct variant.
     ///
     /// E.g., `Bar { .. }` as in `enum Foo { Bar { .. } }`.
-    Struct {
-        fields: ThinVec<FieldDef>,
-        // FIXME: investigate making this a `Option<ErrorGuaranteed>`
-        recovered: bool,
-    },
+    Struct { fields: ThinVec<FieldDef>, recovered: Recovered },
     /// Tuple variant.
     ///
     /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.

compiler/rustc_ast_lowering/src/expr.rs

@@ -158,13 +158,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     let ohs = self.lower_expr(ohs);
                     hir::ExprKind::AddrOf(*k, *m, ohs)
                 }
-                ExprKind::Let(pat, scrutinee, span, is_recovered) => {
+                ExprKind::Let(pat, scrutinee, span, recovered) => {
                     hir::ExprKind::Let(self.arena.alloc(hir::LetExpr {
                         span: self.lower_span(*span),
                         pat: self.lower_pat(pat),
                         ty: None,
                         init: self.lower_expr(scrutinee),
-                        is_recovered: *is_recovered,
+                        recovered: *recovered,
                     }))
                 }
                 ExprKind::If(cond, then, else_opt) => {

compiler/rustc_ast_lowering/src/lib.rs

@@ -1283,7 +1283,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         fields.iter().enumerate().map(|f| this.lower_field_def(f)),
                     );
                     let span = t.span;
-                    let variant_data = hir::VariantData::Struct { fields, recovered: false };
+                    let variant_data =
+                        hir::VariantData::Struct { fields, recovered: ast::Recovered::No };
                     // FIXME: capture the generics from the outer adt.
                     let generics = hir::Generics::empty();
                     let kind = match t.kind {

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -494,7 +494,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 {
                     self.suggest_cloning(err, ty, expr, None, Some(move_spans));
                 } else if self.suggest_hoisting_call_outside_loop(err, expr) {
-                    // The place where the the type moves would be misleading to suggest clone.
+                    // The place where the type moves would be misleading to suggest clone.
                     // #121466
                     self.suggest_cloning(err, ty, expr, None, Some(move_spans));
                 }

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -1326,14 +1326,20 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         })
     }
 
-    // Evaluate whether `sup_region == sub_region`.
-    fn eval_equal(&self, r1: RegionVid, r2: RegionVid) -> bool {
+    /// Evaluate whether `sup_region == sub_region`.
+    ///
+    /// Panics if called before `solve()` executes,
+    // This is `pub` because it's used by unstable external borrowck data users, see `consumers.rs`.
+    pub fn eval_equal(&self, r1: RegionVid, r2: RegionVid) -> bool {
         self.eval_outlives(r1, r2) && self.eval_outlives(r2, r1)
     }
 
-    // Evaluate whether `sup_region: sub_region`.
+    /// Evaluate whether `sup_region: sub_region`.
+    ///
+    /// Panics if called before `solve()` executes,
+    // This is `pub` because it's used by unstable external borrowck data users, see `consumers.rs`.
     #[instrument(skip(self), level = "debug", ret)]
-    fn eval_outlives(&self, sup_region: RegionVid, sub_region: RegionVid) -> bool {
+    pub fn eval_outlives(&self, sup_region: RegionVid, sub_region: RegionVid) -> bool {
         debug!(
             "sup_region's value = {:?} universal={:?}",
             self.region_value_str(sup_region),
@@ -2246,7 +2252,10 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     }
 
     /// Access to the SCC constraint graph.
-    pub(crate) fn constraint_sccs(&self) -> &Sccs<RegionVid, ConstraintSccIndex> {
+    /// This can be used to quickly under-approximate the regions which are equal to each other
+    /// and their relative orderings.
+    // This is `pub` because it's used by unstable external borrowck data users, see `consumers.rs`.
+    pub fn constraint_sccs(&self) -> &Sccs<RegionVid, ConstraintSccIndex> {
         self.constraint_sccs.as_ref()
     }
 

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -40,7 +40,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// compares lifetimes directly, so we need to map the inference variables
     /// back to concrete lifetimes: `'static`, `ReEarlyParam` or `ReLateParam`.
     ///
-    /// First we map the regions in the the generic parameters `_Return<'1>` to
+    /// First we map the regions in the generic parameters `_Return<'1>` to
     /// their `external_name` giving `_Return<'a>`. This step is a bit involved.
     /// See the [rustc-dev-guide chapter] for more info.
     ///

compiler/rustc_builtin_macros/src/format.rs

@@ -7,14 +7,13 @@ use rustc_ast::{token, StmtKind};
 use rustc_ast::{
     Expr, ExprKind, FormatAlignment, FormatArgPosition, FormatArgPositionKind, FormatArgs,
     FormatArgsPiece, FormatArgument, FormatArgumentKind, FormatArguments, FormatCount,
-    FormatDebugHex, FormatOptions, FormatPlaceholder, FormatSign, FormatTrait,
+    FormatDebugHex, FormatOptions, FormatPlaceholder, FormatSign, FormatTrait, Recovered,
 };
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{Applicability, Diag, MultiSpan, PResult, SingleLabelManySpans};
 use rustc_expand::base::*;
 use rustc_lint_defs::builtin::NAMED_ARGUMENTS_USED_POSITIONALLY;
 use rustc_lint_defs::{BufferedEarlyLint, BuiltinLintDiag, LintId};
-use rustc_parse::parser::Recovered;
 use rustc_parse_format as parse;
 use rustc_span::symbol::{Ident, Symbol};
 use rustc_span::{BytePos, ErrorGuaranteed, InnerSpan, Span};
@@ -112,7 +111,7 @@ fn parse_args<'a>(ecx: &ExtCtxt<'a>, sp: Span, tts: TokenStream) -> PResult<'a,
                         _ => return Err(err),
                     }
                 }
-                Ok(Recovered::Yes) => (),
+                Ok(Recovered::Yes(_)) => (),
                 Ok(Recovered::No) => unreachable!(),
             }
         }

compiler/rustc_const_eval/messages.ftl

@@ -69,9 +69,6 @@ const_eval_deref_function_pointer =
     accessing {$allocation} which contains a function
 const_eval_deref_vtable_pointer =
     accessing {$allocation} which contains a vtable
-const_eval_different_allocations =
-    `{$name}` called on pointers into different allocations
-
 const_eval_division_by_zero =
     dividing by zero
 const_eval_division_overflow =
@@ -234,12 +231,18 @@ const_eval_not_enough_caller_args =
 const_eval_nullary_intrinsic_fail =
     could not evaluate nullary intrinsic
 
+const_eval_offset_from_different_allocations =
+    `{$name}` called on pointers into different allocations
+const_eval_offset_from_different_integers =
+    `{$name}` called on different pointers without provenance (i.e., without an associated allocation)
 const_eval_offset_from_overflow =
     `{$name}` called when first pointer is too far ahead of second
-
-const_eval_offset_from_test = out-of-bounds `offset_from`
+const_eval_offset_from_test =
+    out-of-bounds `offset_from`
 const_eval_offset_from_underflow =
     `{$name}` called when first pointer is too far before second
+const_eval_offset_from_unsigned_overflow =
+    `ptr_offset_from_unsigned` called when first pointer has smaller offset than second: {$a_offset} < {$b_offset}
 
 const_eval_operator_non_const =
     cannot call non-const operator in {const_eval_const_context}s
@@ -381,8 +384,6 @@ const_eval_unreachable = entering unreachable code
 const_eval_unreachable_unwind =
     unwinding past a stack frame that does not allow unwinding
 
-const_eval_unsigned_offset_from_overflow =
-    `ptr_offset_from_unsigned` called when first pointer has smaller offset than second: {$a_offset} < {$b_offset}
 const_eval_unsized_local = unsized locals are not supported
 const_eval_unstable_const_fn = `{$def_path}` is not yet stable as a const fn
 

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -8,21 +8,16 @@ use rustc_middle::ty::layout::{LayoutOf as _, ValidityRequirement};
 use rustc_middle::ty::GenericArgsRef;
 use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_middle::{
-    mir::{
-        self,
-        interpret::{
-            Allocation, ConstAllocation, GlobalId, InterpResult, PointerArithmetic, Scalar,
-        },
-        BinOp, ConstValue, NonDivergingIntrinsic,
-    },
+    mir::{self, BinOp, ConstValue, NonDivergingIntrinsic},
     ty::layout::TyAndLayout,
 };
 use rustc_span::symbol::{sym, Symbol};
 use rustc_target::abi::Size;
 
 use super::{
-    memory::MemoryKind, util::ensure_monomorphic_enough, CheckInAllocMsg, ImmTy, InterpCx,
-    MPlaceTy, Machine, OpTy, Pointer,
+    memory::MemoryKind, util::ensure_monomorphic_enough, Allocation, CheckInAllocMsg,
+    ConstAllocation, GlobalId, ImmTy, InterpCx, InterpResult, MPlaceTy, Machine, OpTy, Pointer,
+    PointerArithmetic, Scalar,
 };
 
 use crate::fluent_generated as fluent;
@@ -249,22 +244,30 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     match (self.ptr_try_get_alloc_id(a), self.ptr_try_get_alloc_id(b)) {
                         (Err(a), Err(b)) => {
                             // Neither pointer points to an allocation.
-                            // If these are inequal or null, this *will* fail the deref check below.
+                            // This is okay only if they are the same.
+                            if a != b {
+                                // We'd catch this below in the "dereferenceable" check, but
+                                // show a nicer error for this particular case.
+                                throw_ub_custom!(
+                                    fluent::const_eval_offset_from_different_integers,
+                                    name = intrinsic_name,
+                                );
+                            }
                             (a, b)
                         }
                         (Err(_), _) | (_, Err(_)) => {
                             // We managed to find a valid allocation for one pointer, but not the other.
                             // That means they are definitely not pointing to the same allocation.
                             throw_ub_custom!(
-                                fluent::const_eval_different_allocations,
+                                fluent::const_eval_offset_from_different_allocations,
                                 name = intrinsic_name,
                             );
                         }
                         (Ok((a_alloc_id, a_offset, _)), Ok((b_alloc_id, b_offset, _))) => {
                             // Found allocation for both. They must be into the same allocation.
                             if a_alloc_id != b_alloc_id {
                                 throw_ub_custom!(
-                                    fluent::const_eval_different_allocations,
+                                    fluent::const_eval_offset_from_different_allocations,
                                     name = intrinsic_name,
                                 );
                             }
@@ -286,7 +289,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         // a < b
                         if intrinsic_name == sym::ptr_offset_from_unsigned {
                             throw_ub_custom!(
-                                fluent::const_eval_unsigned_offset_from_overflow,
+                                fluent::const_eval_offset_from_unsigned_overflow,
                                 a_offset = a_offset,
                                 b_offset = b_offset,
                             );

compiler/rustc_expand/src/placeholders.rs

@@ -174,7 +174,10 @@ pub(crate) fn placeholder(
         }]),
         AstFragmentKind::Variants => AstFragment::Variants(smallvec![ast::Variant {
             attrs: Default::default(),
-            data: ast::VariantData::Struct { fields: Default::default(), recovered: false },
+            data: ast::VariantData::Struct {
+                fields: Default::default(),
+                recovered: ast::Recovered::No
+            },
             disr_expr: None,
             id,
             ident,