Rollup merge of rust-lang#97292 - compiler-errors:tcxify-rustc, r=davidtwco

Lifetime variance fixes for rustc

rust-lang#97287 migrates rustc to a `Ty` type that is invariant over its lifetime `'tcx`, so I need to fix a bunch of places that assume that `Ty<'a>` and `Ty<'b>` can be unified by shortening both to some common lifetime.

This is doable, since many lifetimes are already `'tcx`, so all this PR does is be a bit more explicit that elided lifetimes are actually `'tcx`.

Split out from rust-lang#97287 so the compiler team can review independently.

Author: Dylan-DPC

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -1,5 +1,6 @@
 use either::Either;
 use rustc_const_eval::util::CallKind;
+use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan};
 use rustc_hir as hir;
@@ -1622,10 +1623,10 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         location: Location,
         mpi: MovePathIndex,
     ) -> (Vec<MoveSite>, Vec<Location>) {
-        fn predecessor_locations<'a>(
-            body: &'a mir::Body<'_>,
+        fn predecessor_locations<'tcx, 'a>(
+            body: &'a mir::Body<'tcx>,
             location: Location,
-        ) -> impl Iterator<Item = Location> + 'a {
+        ) -> impl Iterator<Item = Location> + Captures<'tcx> + 'a {
             if location.statement_index == 0 {
                 let predecessors = body.predecessors()[location.block].to_vec();
                 Either::Left(predecessors.into_iter().map(move |bb| body.terminator_loc(bb)))

compiler/rustc_borrowck/src/member_constraints.rs

@@ -1,3 +1,4 @@
+use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_index::vec::IndexVec;
 use rustc_middle::infer::MemberConstraint;
@@ -140,11 +141,13 @@ where
     }
 }
 
-impl<R> MemberConstraintSet<'_, R>
+impl<'tcx, R> MemberConstraintSet<'tcx, R>
 where
     R: Copy + Hash + Eq,
 {
-    pub(crate) fn all_indices(&self) -> impl Iterator<Item = NllMemberConstraintIndex> + '_ {
+    pub(crate) fn all_indices(
+        &self,
+    ) -> impl Iterator<Item = NllMemberConstraintIndex> + Captures<'tcx> + '_ {
         self.constraints.indices()
     }
 
@@ -154,7 +157,7 @@ where
     pub(crate) fn indices(
         &self,
         member_region_vid: R,
-    ) -> impl Iterator<Item = NllMemberConstraintIndex> + '_ {
+    ) -> impl Iterator<Item = NllMemberConstraintIndex> + Captures<'tcx> + '_ {
         let mut next = self.first_constraints.get(&member_region_vid).cloned();
         std::iter::from_fn(move || -> Option<NllMemberConstraintIndex> {
             if let Some(current) = next {

compiler/rustc_borrowck/src/type_check/liveness/polonius.rs

@@ -10,17 +10,17 @@ use super::TypeChecker;
 type VarPointRelation = Vec<(Local, LocationIndex)>;
 type PathPointRelation = Vec<(MovePathIndex, LocationIndex)>;
 
-struct UseFactsExtractor<'me> {
+struct UseFactsExtractor<'me, 'tcx> {
     var_defined_at: &'me mut VarPointRelation,
     var_used_at: &'me mut VarPointRelation,
     location_table: &'me LocationTable,
     var_dropped_at: &'me mut VarPointRelation,
-    move_data: &'me MoveData<'me>,
+    move_data: &'me MoveData<'tcx>,
     path_accessed_at_base: &'me mut PathPointRelation,
 }
 
 // A Visitor to walk through the MIR and extract point-wise facts
-impl UseFactsExtractor<'_> {
+impl UseFactsExtractor<'_, '_> {
     fn location_to_index(&self, location: Location) -> LocationIndex {
         self.location_table.mid_index(location)
     }
@@ -53,7 +53,7 @@ impl UseFactsExtractor<'_> {
     }
 }
 
-impl Visitor<'_> for UseFactsExtractor<'_> {
+impl<'a, 'tcx> Visitor<'tcx> for UseFactsExtractor<'a, 'tcx> {
     fn visit_local(&mut self, &local: &Local, context: PlaceContext, location: Location) {
         match def_use::categorize(context) {
             Some(DefUse::Def) => self.insert_def(local, location),
@@ -63,7 +63,7 @@ impl Visitor<'_> for UseFactsExtractor<'_> {
         }
     }
 
-    fn visit_place(&mut self, place: &Place<'_>, context: PlaceContext, location: Location) {
+    fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
         self.super_place(place, context, location);
         match context {
             PlaceContext::NonMutatingUse(_) => {
@@ -82,11 +82,11 @@ impl Visitor<'_> for UseFactsExtractor<'_> {
     }
 }
 
-pub(super) fn populate_access_facts<'tcx>(
-    typeck: &mut TypeChecker<'_, 'tcx>,
+pub(super) fn populate_access_facts<'a, 'tcx>(
+    typeck: &mut TypeChecker<'a, 'tcx>,
     body: &Body<'tcx>,
     location_table: &LocationTable,
-    move_data: &MoveData<'_>,
+    move_data: &MoveData<'tcx>,
     dropped_at: &mut Vec<(Local, Location)>,
 ) {
     debug!("populate_access_facts()");

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -197,7 +197,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         size: Size,
         align: Align,
         kind: MemoryKind<M::MemoryKind>,
-    ) -> InterpResult<'static, Pointer<M::PointerTag>> {
+    ) -> InterpResult<'tcx, Pointer<M::PointerTag>> {
         let alloc = Allocation::uninit(size, align, M::PANIC_ON_ALLOC_FAIL)?;
         Ok(self.allocate_raw_ptr(alloc, kind))
     }
@@ -402,7 +402,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         msg: CheckInAllocMsg,
         alloc_size: impl FnOnce(AllocId, Size, M::TagExtra) -> InterpResult<'tcx, (Size, Align, T)>,
     ) -> InterpResult<'tcx, Option<T>> {
-        fn check_offset_align(offset: u64, align: Align) -> InterpResult<'static> {
+        fn check_offset_align<'tcx>(offset: u64, align: Align) -> InterpResult<'tcx> {
             if offset % align.bytes() == 0 {
                 Ok(())
             } else {
@@ -654,7 +654,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         &self,
         id: AllocId,
         liveness: AllocCheck,
-    ) -> InterpResult<'static, (Size, Align)> {
+    ) -> InterpResult<'tcx, (Size, Align)> {
         // # Regular allocations
         // Don't use `self.get_raw` here as that will
         // a) cause cycles in case `id` refers to a static

compiler/rustc_const_eval/src/interpret/place.rs

@@ -1011,7 +1011,7 @@ where
         &mut self,
         layout: TyAndLayout<'tcx>,
         kind: MemoryKind<M::MemoryKind>,
-    ) -> InterpResult<'static, MPlaceTy<'tcx, M::PointerTag>> {
+    ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {
         let ptr = self.allocate_ptr(layout.size, layout.align.abi, kind)?;
         Ok(MPlaceTy::from_aligned_ptr(ptr.into(), layout))
     }

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs

@@ -98,7 +98,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         &self,
         anon_region: Region<'tcx>,
         replace_region: Region<'tcx>,
-    ) -> Option<AnonymousParamInfo<'_>> {
+    ) -> Option<AnonymousParamInfo<'tcx>> {
         find_param_with_region(self.tcx(), anon_region, replace_region)
     }
 

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

@@ -171,7 +171,7 @@ impl<Tag> Allocation<Tag> {
 
     /// Try to create an Allocation of `size` bytes, failing if there is not enough memory
     /// available to the compiler to do so.
-    pub fn uninit(size: Size, align: Align, panic_on_fail: bool) -> InterpResult<'static, Self> {
+    pub fn uninit<'tcx>(size: Size, align: Align, panic_on_fail: bool) -> InterpResult<'tcx, Self> {
         let bytes = Box::<[u8]>::try_new_zeroed_slice(size.bytes_usize()).map_err(|_| {
             // This results in an error that can happen non-deterministically, since the memory
             // available to the compiler can change between runs. Normally queries are always

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

@@ -397,90 +397,90 @@ impl<'tcx, Tag: Provenance> Scalar<Tag> {
     /// Converts the scalar to produce an unsigned integer of the given size.
     /// Fails if the scalar is a pointer.
     #[inline]
-    pub fn to_uint(self, size: Size) -> InterpResult<'static, u128> {
+    pub fn to_uint(self, size: Size) -> InterpResult<'tcx, u128> {
         self.to_bits(size)
     }
 
     /// Converts the scalar to produce a `u8`. Fails if the scalar is a pointer.
-    pub fn to_u8(self) -> InterpResult<'static, u8> {
+    pub fn to_u8(self) -> InterpResult<'tcx, u8> {
         self.to_uint(Size::from_bits(8)).map(|v| u8::try_from(v).unwrap())
     }
 
     /// Converts the scalar to produce a `u16`. Fails if the scalar is a pointer.
-    pub fn to_u16(self) -> InterpResult<'static, u16> {
+    pub fn to_u16(self) -> InterpResult<'tcx, u16> {
         self.to_uint(Size::from_bits(16)).map(|v| u16::try_from(v).unwrap())
     }
 
     /// Converts the scalar to produce a `u32`. Fails if the scalar is a pointer.
-    pub fn to_u32(self) -> InterpResult<'static, u32> {
+    pub fn to_u32(self) -> InterpResult<'tcx, u32> {
         self.to_uint(Size::from_bits(32)).map(|v| u32::try_from(v).unwrap())
     }
 
     /// Converts the scalar to produce a `u64`. Fails if the scalar is a pointer.
-    pub fn to_u64(self) -> InterpResult<'static, u64> {
+    pub fn to_u64(self) -> InterpResult<'tcx, u64> {
         self.to_uint(Size::from_bits(64)).map(|v| u64::try_from(v).unwrap())
     }
 
     /// Converts the scalar to produce a `u128`. Fails if the scalar is a pointer.
-    pub fn to_u128(self) -> InterpResult<'static, u128> {
+    pub fn to_u128(self) -> InterpResult<'tcx, u128> {
         self.to_uint(Size::from_bits(128))
     }
 
     /// Converts the scalar to produce a machine-pointer-sized unsigned integer.
     /// Fails if the scalar is a pointer.
-    pub fn to_machine_usize(self, cx: &impl HasDataLayout) -> InterpResult<'static, u64> {
+    pub fn to_machine_usize(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, u64> {
         let b = self.to_uint(cx.data_layout().pointer_size)?;
         Ok(u64::try_from(b).unwrap())
     }
 
     /// Converts the scalar to produce a signed integer of the given size.
     /// Fails if the scalar is a pointer.
     #[inline]
-    pub fn to_int(self, size: Size) -> InterpResult<'static, i128> {
+    pub fn to_int(self, size: Size) -> InterpResult<'tcx, i128> {
         let b = self.to_bits(size)?;
         Ok(size.sign_extend(b) as i128)
     }
 
     /// Converts the scalar to produce an `i8`. Fails if the scalar is a pointer.
-    pub fn to_i8(self) -> InterpResult<'static, i8> {
+    pub fn to_i8(self) -> InterpResult<'tcx, i8> {
         self.to_int(Size::from_bits(8)).map(|v| i8::try_from(v).unwrap())
     }
 
     /// Converts the scalar to produce an `i16`. Fails if the scalar is a pointer.
-    pub fn to_i16(self) -> InterpResult<'static, i16> {
+    pub fn to_i16(self) -> InterpResult<'tcx, i16> {
         self.to_int(Size::from_bits(16)).map(|v| i16::try_from(v).unwrap())
     }
 
     /// Converts the scalar to produce an `i32`. Fails if the scalar is a pointer.
-    pub fn to_i32(self) -> InterpResult<'static, i32> {
+    pub fn to_i32(self) -> InterpResult<'tcx, i32> {
         self.to_int(Size::from_bits(32)).map(|v| i32::try_from(v).unwrap())
     }
 
     /// Converts the scalar to produce an `i64`. Fails if the scalar is a pointer.
-    pub fn to_i64(self) -> InterpResult<'static, i64> {
+    pub fn to_i64(self) -> InterpResult<'tcx, i64> {
         self.to_int(Size::from_bits(64)).map(|v| i64::try_from(v).unwrap())
     }
 
     /// Converts the scalar to produce an `i128`. Fails if the scalar is a pointer.
-    pub fn to_i128(self) -> InterpResult<'static, i128> {
+    pub fn to_i128(self) -> InterpResult<'tcx, i128> {
         self.to_int(Size::from_bits(128))
     }
 
     /// Converts the scalar to produce a machine-pointer-sized signed integer.
     /// Fails if the scalar is a pointer.
-    pub fn to_machine_isize(self, cx: &impl HasDataLayout) -> InterpResult<'static, i64> {
+    pub fn to_machine_isize(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, i64> {
         let b = self.to_int(cx.data_layout().pointer_size)?;
         Ok(i64::try_from(b).unwrap())
     }
 
     #[inline]
-    pub fn to_f32(self) -> InterpResult<'static, Single> {
+    pub fn to_f32(self) -> InterpResult<'tcx, Single> {
         // Going through `u32` to check size and truncation.
         Ok(Single::from_bits(self.to_u32()?.into()))
     }
 
     #[inline]
-    pub fn to_f64(self) -> InterpResult<'static, Double> {
+    pub fn to_f64(self) -> InterpResult<'tcx, Double> {
         // Going through `u64` to check size and truncation.
         Ok(Double::from_bits(self.to_u64()?.into()))
     }
@@ -534,7 +534,7 @@ impl<Tag> ScalarMaybeUninit<Tag> {
     }
 
     #[inline]
-    pub fn check_init(self) -> InterpResult<'static, Scalar<Tag>> {
+    pub fn check_init<'tcx>(self) -> InterpResult<'tcx, Scalar<Tag>> {
         match self {
             ScalarMaybeUninit::Scalar(scalar) => Ok(scalar),
             ScalarMaybeUninit::Uninit => throw_ub!(InvalidUninitBytes(None)),

compiler/rustc_middle/src/mir/mod.rs

@@ -13,6 +13,7 @@ use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef};
 use crate::ty::{self, List, Ty, TyCtxt};
 use crate::ty::{AdtDef, InstanceDef, Region, ScalarInt, UserTypeAnnotationIndex};
 
+use rustc_data_structures::captures::Captures;
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def::{CtorKind, Namespace};
 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
@@ -484,7 +485,7 @@ impl<'tcx> Body<'tcx> {
 
     /// Returns an iterator over all user-declared mutable locals.
     #[inline]
-    pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
+    pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + Captures<'tcx> + 'a {
         (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
             let local = Local::new(index);
             let decl = &self.local_decls[local];
@@ -498,7 +499,9 @@ impl<'tcx> Body<'tcx> {
 
     /// Returns an iterator over all user-declared mutable arguments and locals.
     #[inline]
-    pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
+    pub fn mut_vars_and_args_iter<'a>(
+        &'a self,
+    ) -> impl Iterator<Item = Local> + Captures<'tcx> + 'a {
         (1..self.local_decls.len()).filter_map(move |index| {
             let local = Local::new(index);
             let decl = &self.local_decls[local];

compiler/rustc_middle/src/mir/patch.rs

@@ -192,7 +192,7 @@ impl<'tcx> MirPatch<'tcx> {
         }
     }
 
-    pub fn source_info_for_location(&self, body: &Body<'_>, loc: Location) -> SourceInfo {
+    pub fn source_info_for_location(&self, body: &Body<'tcx>, loc: Location) -> SourceInfo {
         let data = match loc.block.index().checked_sub(body.basic_blocks().len()) {
             Some(new) => &self.new_blocks[new],
             None => &body[loc.block],

compiler/rustc_middle/src/traits/mod.rs

@@ -115,8 +115,6 @@ impl Hash for ObligationCause<'_> {
     }
 }
 
-const MISC_OBLIGATION_CAUSE_CODE: ObligationCauseCode<'static> = MiscObligation;
-
 impl<'tcx> ObligationCause<'tcx> {
     #[inline]
     pub fn new(
@@ -201,7 +199,7 @@ pub struct UnifyReceiverContext<'tcx> {
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Lift, Default)]
 pub struct InternedObligationCauseCode<'tcx> {
-    /// `None` for `MISC_OBLIGATION_CAUSE_CODE` (a common case, occurs ~60% of
+    /// `None` for `ObligationCauseCode::MiscObligation` (a common case, occurs ~60% of
     /// the time). `Some` otherwise.
     code: Option<Lrc<ObligationCauseCode<'tcx>>>,
 }
@@ -210,7 +208,11 @@ impl<'tcx> ObligationCauseCode<'tcx> {
     #[inline(always)]
     fn into(self) -> InternedObligationCauseCode<'tcx> {
         InternedObligationCauseCode {
-            code: if let MISC_OBLIGATION_CAUSE_CODE = self { None } else { Some(Lrc::new(self)) },
+            code: if let ObligationCauseCode::MiscObligation = self {
+                None
+            } else {
+                Some(Lrc::new(self))
+            },
         }
     }
 }
@@ -219,7 +221,7 @@ impl<'tcx> std::ops::Deref for InternedObligationCauseCode<'tcx> {
     type Target = ObligationCauseCode<'tcx>;
 
     fn deref(&self) -> &Self::Target {
-        self.code.as_deref().unwrap_or(&MISC_OBLIGATION_CAUSE_CODE)
+        self.code.as_deref().unwrap_or(&ObligationCauseCode::MiscObligation)
     }
 }
 

compiler/rustc_middle/src/ty/layout.rs

@@ -2163,7 +2163,7 @@ impl<'tcx> SizeSkeleton<'tcx> {
         }
     }
 
-    pub fn same_size(self, other: SizeSkeleton<'_>) -> bool {
+    pub fn same_size(self, other: SizeSkeleton<'tcx>) -> bool {
         match (self, other) {
             (SizeSkeleton::Known(a), SizeSkeleton::Known(b)) => a == b,
             (SizeSkeleton::Pointer { tail: a, .. }, SizeSkeleton::Pointer { tail: b, .. }) => {