diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs index 48d09f2c2b2a4..d676906ff5e78 100644 --- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs +++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs @@ -2828,6 +2828,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { } ProjectionElem::ConstantIndex { .. } | ProjectionElem::Subslice { .. } + | ProjectionElem::Subtype(_) | ProjectionElem::Index(_) => kind, }, place_ty.projection_ty(tcx, elem), diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs index f70263e9dcf01..c3cf7db32b149 100644 --- a/compiler/rustc_borrowck/src/diagnostics/mod.rs +++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs @@ -242,6 +242,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { ProjectionElem::Downcast(..) if opt.including_downcast => return None, ProjectionElem::Downcast(..) => (), ProjectionElem::OpaqueCast(..) => (), + ProjectionElem::Subtype(..) => (), ProjectionElem::Field(field, _ty) => { // FIXME(project-rfc_2229#36): print capture precisely here. if let Some(field) = self.is_upvar_field_projection(PlaceRef { @@ -322,7 +323,9 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { PlaceRef { local, projection: proj_base }.ty(self.body, self.infcx.tcx) } ProjectionElem::Downcast(..) => place.ty(self.body, self.infcx.tcx), - ProjectionElem::OpaqueCast(ty) => PlaceTy::from_ty(*ty), + ProjectionElem::Subtype(ty) | ProjectionElem::OpaqueCast(ty) => { + PlaceTy::from_ty(*ty) + } ProjectionElem::Field(_, field_type) => PlaceTy::from_ty(*field_type), }, }; diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs index a0edeec59d058..8ca57383e82d2 100644 --- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs +++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs @@ -159,6 +159,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> { [ .., ProjectionElem::Index(_) + | ProjectionElem::Subtype(_) | ProjectionElem::ConstantIndex { .. } | ProjectionElem::OpaqueCast { .. } | ProjectionElem::Subslice { .. } diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs index 8115c61e89d30..990f098efc5bf 100644 --- a/compiler/rustc_borrowck/src/lib.rs +++ b/compiler/rustc_borrowck/src/lib.rs @@ -1803,6 +1803,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { for (place_base, elem) in place.iter_projections().rev() { match elem { ProjectionElem::Index(_/*operand*/) | + ProjectionElem::Subtype(_) | ProjectionElem::OpaqueCast(_) | ProjectionElem::ConstantIndex { .. } | // assigning to P[i] requires P to be valid. @@ -2191,6 +2192,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { | ProjectionElem::Index(..) | ProjectionElem::ConstantIndex { .. } | ProjectionElem::Subslice { .. } + | ProjectionElem::Subtype(..) | ProjectionElem::OpaqueCast { .. } | ProjectionElem::Downcast(..) => { let upvar_field_projection = self.is_upvar_field_projection(place); diff --git a/compiler/rustc_borrowck/src/places_conflict.rs b/compiler/rustc_borrowck/src/places_conflict.rs index c02f6f3b68782..539d0837659c8 100644 --- a/compiler/rustc_borrowck/src/places_conflict.rs +++ b/compiler/rustc_borrowck/src/places_conflict.rs @@ -249,6 +249,7 @@ fn place_components_conflict<'tcx>( | (ProjectionElem::ConstantIndex { .. }, _, _) | (ProjectionElem::Subslice { .. }, _, _) | (ProjectionElem::OpaqueCast { .. }, _, _) + | (ProjectionElem::Subtype(_), _, _) | (ProjectionElem::Downcast { .. }, _, _) => { // Recursive case. This can still be disjoint on a // further iteration if this a shallow access and @@ -508,6 +509,7 @@ fn place_projection_conflict<'tcx>( | ProjectionElem::Field(..) | ProjectionElem::Index(..) | ProjectionElem::ConstantIndex { .. } + | ProjectionElem::Subtype(_) | ProjectionElem::OpaqueCast { .. } | ProjectionElem::Subslice { .. } | ProjectionElem::Downcast(..), diff --git a/compiler/rustc_borrowck/src/prefixes.rs b/compiler/rustc_borrowck/src/prefixes.rs index 6f28134986376..e9c9709bd1f1a 100644 --- a/compiler/rustc_borrowck/src/prefixes.rs +++ b/compiler/rustc_borrowck/src/prefixes.rs @@ -89,6 +89,9 @@ impl<'cx, 'tcx> Iterator for Prefixes<'cx, 'tcx> { cursor = cursor_base; continue 'cursor; } + ProjectionElem::Subtype(..) => { + panic!("Subtype projection is not allowed before borrow check") + } ProjectionElem::Deref => { // (handled below) } diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs index 9b952f3fe3625..e7b1a489f5d7c 100644 --- a/compiler/rustc_borrowck/src/type_check/mod.rs +++ b/compiler/rustc_borrowck/src/type_check/mod.rs @@ -716,6 +716,9 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> { } PlaceTy::from_ty(fty) } + ProjectionElem::Subtype(_) => { + bug!("ProjectionElem::Subtype shouldn't exist in borrowck") + } ProjectionElem::OpaqueCast(ty) => { let ty = self.sanitize_type(place, ty); let ty = self.cx.normalize(ty, location); @@ -2563,6 +2566,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> { | ProjectionElem::Subslice { .. } => { // other field access } + ProjectionElem::Subtype(_) => { + bug!("ProjectionElem::Subtype shouldn't exist in borrowck") + } } } } diff --git a/compiler/rustc_codegen_cranelift/src/base.rs b/compiler/rustc_codegen_cranelift/src/base.rs index 6d55fdc307401..0a451dad9d232 100644 --- a/compiler/rustc_codegen_cranelift/src/base.rs +++ b/compiler/rustc_codegen_cranelift/src/base.rs @@ -876,6 +876,7 @@ pub(crate) fn codegen_place<'tcx>( cplace = cplace.place_deref(fx); } PlaceElem::OpaqueCast(ty) => bug!("encountered OpaqueCast({ty}) in codegen"), + PlaceElem::Subtype(ty) => cplace = cplace.place_transmute_type(fx, fx.monomorphize(ty)), PlaceElem::Field(field, _ty) => { cplace = cplace.place_field(fx, field); } diff --git a/compiler/rustc_codegen_cranelift/src/value_and_place.rs b/compiler/rustc_codegen_cranelift/src/value_and_place.rs index d4273c0b593ac..45893a4f3ac43 100644 --- a/compiler/rustc_codegen_cranelift/src/value_and_place.rs +++ b/compiler/rustc_codegen_cranelift/src/value_and_place.rs @@ -674,6 +674,16 @@ impl<'tcx> CPlace<'tcx> { } } + /// Used for `ProjectionElem::Subtype`, `ty` has to be monomorphized before + /// passed on. + pub(crate) fn place_transmute_type( + self, + fx: &mut FunctionCx<'_, '_, 'tcx>, + ty: Ty<'tcx>, + ) -> CPlace<'tcx> { + CPlace { inner: self.inner, layout: fx.layout_of(ty) } + } + pub(crate) fn place_field( self, fx: &mut FunctionCx<'_, '_, 'tcx>, diff --git a/compiler/rustc_codegen_ssa/src/mir/place.rs b/compiler/rustc_codegen_ssa/src/mir/place.rs index f775711f87020..eb590a45a63f2 100644 --- a/compiler/rustc_codegen_ssa/src/mir/place.rs +++ b/compiler/rustc_codegen_ssa/src/mir/place.rs @@ -466,6 +466,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { mir::ProjectionElem::OpaqueCast(ty) => { bug!("encountered OpaqueCast({ty}) in codegen") } + mir::ProjectionElem::Subtype(ty) => cg_base.project_type(bx, self.monomorphize(ty)), mir::ProjectionElem::Index(index) => { let index = &mir::Operand::Copy(mir::Place::from(index)); let index = self.codegen_operand(bx, index); diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs index 94a5cc67d31c8..af7dfbef2ff81 100644 --- a/compiler/rustc_const_eval/src/interpret/eval_context.rs +++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs @@ -13,7 +13,7 @@ use rustc_middle::ty::layout::{ self, FnAbiError, FnAbiOfHelpers, FnAbiRequest, LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout, }; -use rustc_middle::ty::{self, GenericArgsRef, ParamEnv, Ty, TyCtxt, TypeFoldable}; +use rustc_middle::ty::{self, GenericArgsRef, ParamEnv, Ty, TyCtxt, TypeFoldable, Variance}; use rustc_mir_dataflow::storage::always_storage_live_locals; use rustc_session::Limit; use rustc_span::Span; @@ -384,7 +384,7 @@ pub(super) fn mir_assign_valid_types<'tcx>( // all normal lifetimes are erased, higher-ranked types with their // late-bound lifetimes are still around and can lead to type // differences. - if util::is_subtype(tcx, param_env, src.ty, dest.ty) { + if util::relate_types(tcx, param_env, Variance::Covariant, src.ty, dest.ty) { // Make sure the layout is equal, too -- just to be safe. Miri really // needs layout equality. For performance reason we skip this check when // the types are equal. Equal types *can* have different layouts when diff --git a/compiler/rustc_const_eval/src/interpret/projection.rs b/compiler/rustc_const_eval/src/interpret/projection.rs index f462c13816ee8..70df3d8fd782c 100644 --- a/compiler/rustc_const_eval/src/interpret/projection.rs +++ b/compiler/rustc_const_eval/src/interpret/projection.rs @@ -319,6 +319,8 @@ where OpaqueCast(ty) => { span_bug!(self.cur_span(), "OpaqueCast({ty}) encountered after borrowck") } + // We don't want anything happening here, this is here as a dummy. + Subtype(_) => base.transmute(base.layout(), self)?, Field(field, _) => self.project_field(base, field.index())?, Downcast(_, variant) => self.project_downcast(base, variant)?, Deref => self.deref_pointer(&base.to_op(self)?)?.into(), diff --git a/compiler/rustc_const_eval/src/transform/check_consts/check.rs b/compiler/rustc_const_eval/src/transform/check_consts/check.rs index 9d00ade477aae..d380849fefefd 100644 --- a/compiler/rustc_const_eval/src/transform/check_consts/check.rs +++ b/compiler/rustc_const_eval/src/transform/check_consts/check.rs @@ -664,6 +664,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> { | ProjectionElem::Downcast(..) | ProjectionElem::OpaqueCast(..) | ProjectionElem::Subslice { .. } + | ProjectionElem::Subtype(..) | ProjectionElem::Field(..) | ProjectionElem::Index(_) => {} } diff --git a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs index 34e9b76c4844e..de3186a53c165 100644 --- a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs +++ b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs @@ -306,6 +306,7 @@ where ProjectionElem::Index(index) if in_local(index) => return true, ProjectionElem::Deref + | ProjectionElem::Subtype(_) | ProjectionElem::Field(_, _) | ProjectionElem::OpaqueCast(_) | ProjectionElem::ConstantIndex { .. } diff --git a/compiler/rustc_const_eval/src/transform/promote_consts.rs b/compiler/rustc_const_eval/src/transform/promote_consts.rs index 4a9977add78c0..8ede3bdd2b60a 100644 --- a/compiler/rustc_const_eval/src/transform/promote_consts.rs +++ b/compiler/rustc_const_eval/src/transform/promote_consts.rs @@ -357,7 +357,9 @@ impl<'tcx> Validator<'_, 'tcx> { return Err(Unpromotable); } - ProjectionElem::ConstantIndex { .. } | ProjectionElem::Subslice { .. } => {} + ProjectionElem::ConstantIndex { .. } + | ProjectionElem::Subtype(_) + | ProjectionElem::Subslice { .. } => {} ProjectionElem::Index(local) => { let mut promotable = false; diff --git a/compiler/rustc_const_eval/src/transform/validate.rs b/compiler/rustc_const_eval/src/transform/validate.rs index 18b22882e7d08..4711f7b47cccc 100644 --- a/compiler/rustc_const_eval/src/transform/validate.rs +++ b/compiler/rustc_const_eval/src/transform/validate.rs @@ -7,7 +7,7 @@ use rustc_infer::traits::Reveal; use rustc_middle::mir::interpret::Scalar; use rustc_middle::mir::visit::{NonUseContext, PlaceContext, Visitor}; use rustc_middle::mir::*; -use rustc_middle::ty::{self, InstanceDef, ParamEnv, Ty, TyCtxt, TypeVisitableExt}; +use rustc_middle::ty::{self, InstanceDef, ParamEnv, Ty, TyCtxt, TypeVisitableExt, Variance}; use rustc_mir_dataflow::impls::MaybeStorageLive; use rustc_mir_dataflow::storage::always_storage_live_locals; use rustc_mir_dataflow::{Analysis, ResultsCursor}; @@ -16,6 +16,8 @@ use rustc_target::spec::abi::Abi; use crate::util::is_within_packed; +use crate::util::relate_types; + #[derive(Copy, Clone, Debug, PartialEq, Eq)] enum EdgeKind { Unwind, @@ -602,7 +604,15 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> { return true; } - crate::util::is_subtype(self.tcx, self.param_env, src, dest) + // After borrowck subtyping should be fully explicit via + // `Subtype` projections. + let variance = if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) { + Variance::Invariant + } else { + Variance::Covariant + }; + + crate::util::relate_types(self.tcx, self.param_env, variance, src, dest) } } @@ -753,6 +763,23 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> { } } } + ProjectionElem::Subtype(ty) => { + if !relate_types( + self.tcx, + self.param_env, + Variance::Covariant, + ty, + place_ref.ty(&self.body.local_decls, self.tcx).ty, + ) { + self.fail( + location, + format!( + "Failed subtyping {ty:#?} and {:#?}", + place_ref.ty(&self.body.local_decls, self.tcx).ty + ), + ) + } + } _ => {} } self.super_projection_elem(place_ref, elem, context, location); @@ -1088,6 +1115,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> { // LHS and RHS of the assignment must have the same type. let left_ty = dest.ty(&self.body.local_decls, self.tcx).ty; let right_ty = rvalue.ty(&self.body.local_decls, self.tcx); + if !self.mir_assign_valid_types(right_ty, left_ty) { self.fail( location, diff --git a/compiler/rustc_const_eval/src/util/compare_types.rs b/compiler/rustc_const_eval/src/util/compare_types.rs index 83376c8e99289..265ca0c7884ce 100644 --- a/compiler/rustc_const_eval/src/util/compare_types.rs +++ b/compiler/rustc_const_eval/src/util/compare_types.rs @@ -5,7 +5,7 @@ use rustc_infer::infer::TyCtxtInferExt; use rustc_middle::traits::{DefiningAnchor, ObligationCause}; -use rustc_middle::ty::{ParamEnv, Ty, TyCtxt}; +use rustc_middle::ty::{ParamEnv, Ty, TyCtxt, Variance}; use rustc_trait_selection::traits::ObligationCtxt; /// Returns whether the two types are equal up to subtyping. @@ -24,16 +24,22 @@ pub fn is_equal_up_to_subtyping<'tcx>( } // Check for subtyping in either direction. - is_subtype(tcx, param_env, src, dest) || is_subtype(tcx, param_env, dest, src) + relate_types(tcx, param_env, Variance::Covariant, src, dest) + || relate_types(tcx, param_env, Variance::Covariant, dest, src) } /// Returns whether `src` is a subtype of `dest`, i.e. `src <: dest`. /// +/// When validating assignments, the variance should be `Covariant`. When checking +/// during `MirPhase` >= `MirPhase::Runtime(RuntimePhase::Initial)` variance should be `Invariant` +/// because we want to check for type equality. +/// /// This mostly ignores opaque types as it can be used in constraining contexts /// while still computing the final underlying type. -pub fn is_subtype<'tcx>( +pub fn relate_types<'tcx>( tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, + variance: Variance, src: Ty<'tcx>, dest: Ty<'tcx>, ) -> bool { @@ -48,7 +54,7 @@ pub fn is_subtype<'tcx>( let cause = ObligationCause::dummy(); let src = ocx.normalize(&cause, param_env, src); let dest = ocx.normalize(&cause, param_env, dest); - match ocx.sub(&cause, param_env, src, dest) { + match ocx.relate(&cause, param_env, variance, src, dest) { Ok(()) => {} Err(_) => return false, }; diff --git a/compiler/rustc_const_eval/src/util/mod.rs b/compiler/rustc_const_eval/src/util/mod.rs index 0aef7fa469e4b..040b3071e6f87 100644 --- a/compiler/rustc_const_eval/src/util/mod.rs +++ b/compiler/rustc_const_eval/src/util/mod.rs @@ -7,7 +7,7 @@ mod type_name; pub use self::alignment::{is_disaligned, is_within_packed}; pub use self::check_validity_requirement::check_validity_requirement; -pub use self::compare_types::{is_equal_up_to_subtyping, is_subtype}; +pub use self::compare_types::{is_equal_up_to_subtyping, relate_types}; pub use self::type_name::type_name; /// Classify whether an operator is "left-homogeneous", i.e., the LHS has the diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs index 76567c3f6b0a0..9361d32a0d571 100644 --- a/compiler/rustc_middle/src/mir/pretty.rs +++ b/compiler/rustc_middle/src/mir/pretty.rs @@ -1103,6 +1103,7 @@ fn pre_fmt_projection(projection: &[PlaceElem<'_>], fmt: &mut Formatter<'_>) -> for &elem in projection.iter().rev() { match elem { ProjectionElem::OpaqueCast(_) + | ProjectionElem::Subtype(_) | ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => { write!(fmt, "(").unwrap(); @@ -1125,6 +1126,9 @@ fn post_fmt_projection(projection: &[PlaceElem<'_>], fmt: &mut Formatter<'_>) -> ProjectionElem::OpaqueCast(ty) => { write!(fmt, " as {ty})")?; } + ProjectionElem::Subtype(ty) => { + write!(fmt, " as subtype {ty})")?; + } ProjectionElem::Downcast(Some(name), _index) => { write!(fmt, " as {name})")?; } diff --git a/compiler/rustc_middle/src/mir/statement.rs b/compiler/rustc_middle/src/mir/statement.rs index 5ac108bc82900..5864acaed7b23 100644 --- a/compiler/rustc_middle/src/mir/statement.rs +++ b/compiler/rustc_middle/src/mir/statement.rs @@ -57,6 +57,7 @@ impl ProjectionElem { Self::Field(_, _) | Self::Index(_) | Self::OpaqueCast(_) + | Self::Subtype(_) | Self::ConstantIndex { .. } | Self::Subslice { .. } | Self::Downcast(_, _) => false, @@ -70,6 +71,7 @@ impl ProjectionElem { Self::Deref | Self::Index(_) => false, Self::Field(_, _) | Self::OpaqueCast(_) + | Self::Subtype(_) | Self::ConstantIndex { .. } | Self::Subslice { .. } | Self::Downcast(_, _) => true, @@ -95,6 +97,7 @@ impl ProjectionElem { | Self::Field(_, _) => true, Self::ConstantIndex { from_end: true, .. } | Self::Index(_) + | Self::Subtype(_) | Self::OpaqueCast(_) | Self::Subslice { .. } => false, } diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs index 55f895f73b48b..49f4def6dfb63 100644 --- a/compiler/rustc_middle/src/mir/syntax.rs +++ b/compiler/rustc_middle/src/mir/syntax.rs @@ -1075,6 +1075,18 @@ pub enum ProjectionElem { /// Like an explicit cast from an opaque type to a concrete type, but without /// requiring an intermediate variable. OpaqueCast(T), + + /// A `Subtype(T)` projection is applied to any `StatementKind::Assign` where + /// type of lvalue doesn't match the type of rvalue, the primary goal is making subtyping + /// explicit during optimizations and codegen. + /// + /// This projection doesn't impact the runtime behavior of the program except for potentially changing + /// some type metadata of the interpreter or codegen backend. + /// + /// This goal is achieved with mir_transform pass `Subtyper`, which runs right after + /// borrowchecker, as we only care about subtyping that can affect trait selection and + /// `TypeId`. + Subtype(T), } /// Alias for projections as they appear in places, where the base is a place diff --git a/compiler/rustc_middle/src/mir/tcx.rs b/compiler/rustc_middle/src/mir/tcx.rs index 01c04f6389050..44ae75e2de701 100644 --- a/compiler/rustc_middle/src/mir/tcx.rs +++ b/compiler/rustc_middle/src/mir/tcx.rs @@ -69,7 +69,7 @@ impl<'tcx> PlaceTy<'tcx> { param_env: ty::ParamEnv<'tcx>, elem: &ProjectionElem, mut handle_field: impl FnMut(&Self, FieldIdx, T) -> Ty<'tcx>, - mut handle_opaque_cast: impl FnMut(&Self, T) -> Ty<'tcx>, + mut handle_opaque_cast_and_subtype: impl FnMut(&Self, T) -> Ty<'tcx>, ) -> PlaceTy<'tcx> where V: ::std::fmt::Debug, @@ -110,7 +110,12 @@ impl<'tcx> PlaceTy<'tcx> { PlaceTy { ty: self.ty, variant_index: Some(index) } } ProjectionElem::Field(f, fty) => PlaceTy::from_ty(handle_field(&self, f, fty)), - ProjectionElem::OpaqueCast(ty) => PlaceTy::from_ty(handle_opaque_cast(&self, ty)), + ProjectionElem::OpaqueCast(ty) => { + PlaceTy::from_ty(handle_opaque_cast_and_subtype(&self, ty)) + } + ProjectionElem::Subtype(ty) => { + PlaceTy::from_ty(handle_opaque_cast_and_subtype(&self, ty)) + } }; debug!("projection_ty self: {:?} elem: {:?} yields: {:?}", self, elem, answer); answer diff --git a/compiler/rustc_middle/src/mir/visit.rs b/compiler/rustc_middle/src/mir/visit.rs index 51ec6da1ac8ea..60f78bef0afc7 100644 --- a/compiler/rustc_middle/src/mir/visit.rs +++ b/compiler/rustc_middle/src/mir/visit.rs @@ -1109,6 +1109,11 @@ macro_rules! visit_place_fns { self.visit_ty(&mut new_ty, TyContext::Location(location)); if ty != new_ty { Some(PlaceElem::OpaqueCast(new_ty)) } else { None } } + PlaceElem::Subtype(ty) => { + let mut new_ty = ty; + self.visit_ty(&mut new_ty, TyContext::Location(location)); + if ty != new_ty { Some(PlaceElem::Subtype(new_ty)) } else { None } + } PlaceElem::Deref | PlaceElem::ConstantIndex { .. } | PlaceElem::Subslice { .. } @@ -1175,7 +1180,9 @@ macro_rules! visit_place_fns { location: Location, ) { match elem { - ProjectionElem::OpaqueCast(ty) | ProjectionElem::Field(_, ty) => { + ProjectionElem::OpaqueCast(ty) + | ProjectionElem::Subtype(ty) + | ProjectionElem::Field(_, ty) => { self.visit_ty(ty, TyContext::Location(location)); } ProjectionElem::Index(local) => { diff --git a/compiler/rustc_mir_build/src/build/expr/as_place.rs b/compiler/rustc_mir_build/src/build/expr/as_place.rs index 2e7ef265a93c2..4aff406b37686 100644 --- a/compiler/rustc_mir_build/src/build/expr/as_place.rs +++ b/compiler/rustc_mir_build/src/build/expr/as_place.rs @@ -102,7 +102,7 @@ fn convert_to_hir_projections_and_truncate_for_capture( continue; } // These do not affect anything, they just make sure we know the right type. - ProjectionElem::OpaqueCast(_) => continue, + ProjectionElem::OpaqueCast(_) | ProjectionElem::Subtype(..) => continue, ProjectionElem::Index(..) | ProjectionElem::ConstantIndex { .. } | ProjectionElem::Subslice { .. } => { @@ -709,6 +709,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { ProjectionElem::Field(..) | ProjectionElem::Downcast(..) | ProjectionElem::OpaqueCast(..) + | ProjectionElem::Subtype(..) | ProjectionElem::ConstantIndex { .. } | ProjectionElem::Subslice { .. } => (), } diff --git a/compiler/rustc_mir_dataflow/src/move_paths/abs_domain.rs b/compiler/rustc_mir_dataflow/src/move_paths/abs_domain.rs index 7806e8f45d3ad..2a7f23ef6d251 100644 --- a/compiler/rustc_mir_dataflow/src/move_paths/abs_domain.rs +++ b/compiler/rustc_mir_dataflow/src/move_paths/abs_domain.rs @@ -57,6 +57,7 @@ impl<'tcx> Lift for PlaceElem<'tcx> { ProjectionElem::ConstantIndex { offset, min_length, from_end } } ProjectionElem::Downcast(a, u) => ProjectionElem::Downcast(a, u), + ProjectionElem::Subtype(ty) => ProjectionElem::Subtype(ty.lift()), } } } diff --git a/compiler/rustc_mir_dataflow/src/move_paths/builder.rs b/compiler/rustc_mir_dataflow/src/move_paths/builder.rs index 9ced3a7f3cd66..7a5b3585d5971 100644 --- a/compiler/rustc_mir_dataflow/src/move_paths/builder.rs +++ b/compiler/rustc_mir_dataflow/src/move_paths/builder.rs @@ -227,10 +227,13 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> { } _ => bug!("Unexpected type {place_ty:#?}"), }, - // `OpaqueCast` only transmutes the type, so no moves there and - // `Downcast` only changes information about a `Place` without moving + // `OpaqueCast`:Only transmutes the type, so no moves there. + // `Downcast` :Only changes information about a `Place` without moving. + // `Subtype` :Only transmutes the type, so moves. // So it's safe to skip these. - ProjectionElem::OpaqueCast(_) | ProjectionElem::Downcast(_, _) => (), + ProjectionElem::OpaqueCast(_) + | ProjectionElem::Subtype(_) + | ProjectionElem::Downcast(_, _) => (), } if union_path.is_none() { // inlined from add_move_path because of a borrowck conflict with the iterator diff --git a/compiler/rustc_mir_transform/src/add_subtyping_projections.rs b/compiler/rustc_mir_transform/src/add_subtyping_projections.rs new file mode 100644 index 0000000000000..1cc049d5a2265 --- /dev/null +++ b/compiler/rustc_mir_transform/src/add_subtyping_projections.rs @@ -0,0 +1,66 @@ +use crate::MirPass; +use rustc_index::IndexVec; +use rustc_middle::mir::patch::MirPatch; +use rustc_middle::mir::visit::MutVisitor; +use rustc_middle::mir::*; +use rustc_middle::ty::TyCtxt; + +pub struct Subtyper; + +pub struct SubTypeChecker<'a, 'tcx> { + tcx: TyCtxt<'tcx>, + patcher: MirPatch<'tcx>, + local_decls: &'a IndexVec>, +} + +impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeChecker<'a, 'tcx> { + fn tcx(&self) -> TyCtxt<'tcx> { + self.tcx + } + + fn visit_assign( + &mut self, + place: &mut Place<'tcx>, + rvalue: &mut Rvalue<'tcx>, + location: Location, + ) { + let mut place_ty = place.ty(self.local_decls, self.tcx).ty; + let mut rval_ty = rvalue.ty(self.local_decls, self.tcx); + // Not erasing this causes `Free Regions` errors in validator, + // when rval is `ReStatic`. + rval_ty = self.tcx.erase_regions_ty(rval_ty); + place_ty = self.tcx.erase_regions(place_ty); + if place_ty != rval_ty { + let temp = self + .patcher + .new_temp(rval_ty, self.local_decls[place.as_ref().local].source_info.span); + let new_place = Place::from(temp); + self.patcher.add_assign(location, new_place, rvalue.clone()); + let subtyped = new_place.project_deeper(&[ProjectionElem::Subtype(place_ty)], self.tcx); + *rvalue = Rvalue::Use(Operand::Move(subtyped)); + } + } +} + +// Aim here is to do this kind of transformation: +// +// let place: place_ty = rval; +// // gets transformed to +// let temp: rval_ty = rval; +// let place: place_ty = temp as place_ty; +// +pub fn subtype_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { + let patch = MirPatch::new(body); + let mut checker = SubTypeChecker { tcx, patcher: patch, local_decls: &body.local_decls }; + + for (bb, data) in body.basic_blocks.as_mut_preserves_cfg().iter_enumerated_mut() { + checker.visit_basic_block_data(bb, data); + } + checker.patcher.apply(body); +} + +impl<'tcx> MirPass<'tcx> for Subtyper { + fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { + subtype_finder(tcx, body); + } +} diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs index 449bade332261..56bdc5a171acc 100644 --- a/compiler/rustc_mir_transform/src/gvn.rs +++ b/compiler/rustc_mir_transform/src/gvn.rs @@ -306,6 +306,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { } ProjectionElem::Downcast(name, index) => ProjectionElem::Downcast(name, index), ProjectionElem::OpaqueCast(ty) => ProjectionElem::OpaqueCast(ty), + ProjectionElem::Subtype(ty) => ProjectionElem::Subtype(ty), }; value = self.insert(Value::Projection(value, proj)); } diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs index ebd61f8ad9532..b53e0852c0970 100644 --- a/compiler/rustc_mir_transform/src/inline.rs +++ b/compiler/rustc_mir_transform/src/inline.rs @@ -218,7 +218,13 @@ impl<'tcx> Inliner<'tcx> { // Normally, this shouldn't be required, but trait normalization failure can create a // validation ICE. let output_type = callee_body.return_ty(); - if !util::is_subtype(self.tcx, self.param_env, output_type, destination_ty) { + if !util::relate_types( + self.tcx, + self.param_env, + ty::Variance::Covariant, + output_type, + destination_ty, + ) { trace!(?output_type, ?destination_ty); return Err("failed to normalize return type"); } @@ -248,7 +254,13 @@ impl<'tcx> Inliner<'tcx> { self_arg_ty.into_iter().chain(arg_tuple_tys).zip(callee_body.args_iter()) { let input_type = callee_body.local_decls[input].ty; - if !util::is_subtype(self.tcx, self.param_env, input_type, arg_ty) { + if !util::relate_types( + self.tcx, + self.param_env, + ty::Variance::Covariant, + input_type, + arg_ty, + ) { trace!(?arg_ty, ?input_type); return Err("failed to normalize tuple argument type"); } @@ -257,7 +269,13 @@ impl<'tcx> Inliner<'tcx> { for (arg, input) in args.iter().zip(callee_body.args_iter()) { let input_type = callee_body.local_decls[input].ty; let arg_ty = arg.ty(&caller_body.local_decls, self.tcx); - if !util::is_subtype(self.tcx, self.param_env, input_type, arg_ty) { + if !util::relate_types( + self.tcx, + self.param_env, + ty::Variance::Covariant, + input_type, + arg_ty, + ) { trace!(?arg_ty, ?input_type); return Err("failed to normalize argument type"); } diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs index 754f2ee837682..22381844d6dc2 100644 --- a/compiler/rustc_mir_transform/src/lib.rs +++ b/compiler/rustc_mir_transform/src/lib.rs @@ -54,6 +54,7 @@ mod check_packed_ref; pub mod check_unsafety; mod remove_place_mention; // This pass is public to allow external drivers to perform MIR cleanup +mod add_subtyping_projections; pub mod cleanup_post_borrowck; mod const_debuginfo; mod const_goto; @@ -466,6 +467,7 @@ pub fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<' /// After this series of passes, no lifetime analysis based on borrowing can be done. fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { let passes: &[&dyn MirPass<'tcx>] = &[ + &add_subtyping_projections::Subtyper, &cleanup_post_borrowck::CleanupPostBorrowck, &remove_noop_landing_pads::RemoveNoopLandingPads, &simplify::SimplifyCfg::EarlyOpt, diff --git a/compiler/rustc_trait_selection/src/traits/engine.rs b/compiler/rustc_trait_selection/src/traits/engine.rs index 820973dc090ad..015e38b2ac085 100644 --- a/compiler/rustc_trait_selection/src/traits/engine.rs +++ b/compiler/rustc_trait_selection/src/traits/engine.rs @@ -23,6 +23,7 @@ use rustc_middle::traits::query::NoSolution; use rustc_middle::ty::error::TypeError; use rustc_middle::ty::ToPredicate; use rustc_middle::ty::TypeFoldable; +use rustc_middle::ty::Variance; use rustc_middle::ty::{self, Ty, TyCtxt}; use rustc_session::config::TraitSolver; @@ -156,6 +157,20 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> { .map(|infer_ok| self.register_infer_ok_obligations(infer_ok)) } + pub fn relate>( + &self, + cause: &ObligationCause<'tcx>, + param_env: ty::ParamEnv<'tcx>, + variance: Variance, + expected: T, + actual: T, + ) -> Result<(), TypeError<'tcx>> { + self.infcx + .at(cause, param_env) + .relate(DefineOpaqueTypes::Yes, expected, variance, actual) + .map(|infer_ok| self.register_infer_ok_obligations(infer_ok)) + } + /// Checks whether `expected` is a supertype of `actual`: `expected :> actual`. pub fn sup>( &self, diff --git a/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs b/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs index 17233058c9c93..55f9cb27ad4db 100644 --- a/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs +++ b/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs @@ -272,6 +272,7 @@ fn check_place<'tcx>(tcx: TyCtxt<'tcx>, place: Place<'tcx>, span: Span, body: &B | ProjectionElem::Downcast(..) | ProjectionElem::Subslice { .. } | ProjectionElem::Deref + | ProjectionElem::Subtype(_) | ProjectionElem::Index(_) => {}, } } diff --git a/tests/mir-opt/inline/inline_generator.main.Inline.panic-abort.diff b/tests/mir-opt/inline/inline_generator.main.Inline.panic-abort.diff index 6779003b6930e..4a816e024c58a 100644 --- a/tests/mir-opt/inline/inline_generator.main.Inline.panic-abort.diff +++ b/tests/mir-opt/inline/inline_generator.main.Inline.panic-abort.diff @@ -7,11 +7,12 @@ let mut _2: std::pin::Pin<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>; let mut _3: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8}; let mut _4: {generator@$DIR/inline_generator.rs:16:5: 16:8}; -+ let mut _5: bool; ++ let mut _6: bool; scope 1 { debug _r => _1; } + scope 2 (inlined g) { ++ let mut _5: {generator@$DIR/inline_generator.rs:16:5: 16:8}; + } + scope 3 (inlined Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>::new) { + debug pointer => _3; @@ -22,10 +23,10 @@ + } + } + scope 6 (inlined g::{closure#0}) { -+ debug a => _5; -+ let mut _6: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8}; -+ let mut _7: u32; -+ let mut _8: i32; ++ debug a => _6; ++ let mut _7: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8}; ++ let mut _8: u32; ++ let mut _9: i32; + } bb0: { @@ -34,21 +35,24 @@ StorageLive(_3); StorageLive(_4); - _4 = g() -> [return: bb1, unwind unreachable]; -+ _4 = {generator@$DIR/inline_generator.rs:16:5: 16:8 (#0)}; ++ StorageLive(_5); ++ _5 = {generator@$DIR/inline_generator.rs:16:5: 16:8 (#0)}; ++ _4 = move (_5 as subtype {generator@$DIR/inline_generator.rs:16:5: 16:8}); ++ StorageDead(_5); + _3 = &mut _4; + _2 = Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}> { pointer: move _3 }; + StorageDead(_3); -+ StorageLive(_5); -+ _5 = const false; -+ _6 = (_2.0: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8}); -+ _7 = discriminant((*_6)); -+ switchInt(move _7) -> [0: bb3, 1: bb7, 3: bb8, otherwise: bb9]; ++ StorageLive(_6); ++ _6 = const false; ++ _7 = (_2.0: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8}); ++ _8 = discriminant((*_7)); ++ switchInt(move _8) -> [0: bb3, 1: bb7, 3: bb8, otherwise: bb9]; } bb1: { - _3 = &mut _4; - _2 = Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>::new(move _3) -> [return: bb2, unwind unreachable]; -+ StorageDead(_5); ++ StorageDead(_6); + StorageDead(_2); + drop(_4) -> [return: bb2, unwind unreachable]; } @@ -65,8 +69,8 @@ bb3: { - StorageDead(_2); - drop(_4) -> [return: bb4, unwind unreachable]; -+ StorageLive(_8); -+ switchInt(_5) -> [0: bb4, otherwise: bb5]; ++ StorageLive(_9); ++ switchInt(_6) -> [0: bb4, otherwise: bb5]; } bb4: { @@ -74,18 +78,18 @@ - _0 = const (); - StorageDead(_1); - return; -+ _8 = const 13_i32; ++ _9 = const 13_i32; + goto -> bb6; + } + + bb5: { -+ _8 = const 7_i32; ++ _9 = const 7_i32; + goto -> bb6; + } + + bb6: { -+ _1 = GeneratorState::::Yielded(move _8); -+ discriminant((*_6)) = 3; ++ _1 = GeneratorState::::Yielded(move _9); ++ discriminant((*_7)) = 3; + goto -> bb1; + } + @@ -94,10 +98,10 @@ + } + + bb8: { -+ StorageLive(_8); -+ StorageDead(_8); -+ _1 = GeneratorState::::Complete(_5); -+ discriminant((*_6)) = 1; ++ StorageLive(_9); ++ StorageDead(_9); ++ _1 = GeneratorState::::Complete(_6); ++ discriminant((*_7)) = 1; + goto -> bb1; + } + diff --git a/tests/mir-opt/inline/inline_generator.main.Inline.panic-unwind.diff b/tests/mir-opt/inline/inline_generator.main.Inline.panic-unwind.diff index 31744be99ec64..2b910cd6543c8 100644 --- a/tests/mir-opt/inline/inline_generator.main.Inline.panic-unwind.diff +++ b/tests/mir-opt/inline/inline_generator.main.Inline.panic-unwind.diff @@ -7,11 +7,12 @@ let mut _2: std::pin::Pin<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>; let mut _3: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8}; let mut _4: {generator@$DIR/inline_generator.rs:16:5: 16:8}; -+ let mut _5: bool; ++ let mut _6: bool; scope 1 { debug _r => _1; } + scope 2 (inlined g) { ++ let mut _5: {generator@$DIR/inline_generator.rs:16:5: 16:8}; + } + scope 3 (inlined Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>::new) { + debug pointer => _3; @@ -22,10 +23,10 @@ + } + } + scope 6 (inlined g::{closure#0}) { -+ debug a => _5; -+ let mut _6: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8}; -+ let mut _7: u32; -+ let mut _8: i32; ++ debug a => _6; ++ let mut _7: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8}; ++ let mut _8: u32; ++ let mut _9: i32; + } bb0: { @@ -37,7 +38,10 @@ - } - - bb1: { -+ _4 = {generator@$DIR/inline_generator.rs:16:5: 16:8 (#0)}; ++ StorageLive(_5); ++ _5 = {generator@$DIR/inline_generator.rs:16:5: 16:8 (#0)}; ++ _4 = move (_5 as subtype {generator@$DIR/inline_generator.rs:16:5: 16:8}); ++ StorageDead(_5); _3 = &mut _4; - _2 = Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>::new(move _3) -> [return: bb2, unwind: bb5]; - } @@ -46,16 +50,16 @@ + _2 = Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}> { pointer: move _3 }; StorageDead(_3); - _1 = <{generator@$DIR/inline_generator.rs:16:5: 16:8} as Generator>::resume(move _2, const false) -> [return: bb3, unwind: bb5]; -+ StorageLive(_5); -+ _5 = const false; -+ _6 = (_2.0: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8}); -+ _7 = discriminant((*_6)); -+ switchInt(move _7) -> [0: bb5, 1: bb9, 3: bb10, otherwise: bb11]; ++ StorageLive(_6); ++ _6 = const false; ++ _7 = (_2.0: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8}); ++ _8 = discriminant((*_7)); ++ switchInt(move _8) -> [0: bb5, 1: bb9, 3: bb10, otherwise: bb11]; } - bb3: { + bb1: { -+ StorageDead(_5); ++ StorageDead(_6); StorageDead(_2); - drop(_4) -> [return: bb4, unwind: bb6]; + drop(_4) -> [return: bb2, unwind: bb4]; @@ -81,23 +85,23 @@ + } + + bb5: { -+ StorageLive(_8); -+ switchInt(_5) -> [0: bb6, otherwise: bb7]; ++ StorageLive(_9); ++ switchInt(_6) -> [0: bb6, otherwise: bb7]; + } + + bb6: { -+ _8 = const 13_i32; ++ _9 = const 13_i32; + goto -> bb8; + } + + bb7: { -+ _8 = const 7_i32; ++ _9 = const 7_i32; + goto -> bb8; + } + + bb8: { -+ _1 = GeneratorState::::Yielded(move _8); -+ discriminant((*_6)) = 3; ++ _1 = GeneratorState::::Yielded(move _9); ++ discriminant((*_7)) = 3; + goto -> bb1; + } + @@ -106,10 +110,10 @@ + } + + bb10: { -+ StorageLive(_8); -+ StorageDead(_8); -+ _1 = GeneratorState::::Complete(_5); -+ discriminant((*_6)) = 1; ++ StorageLive(_9); ++ StorageDead(_9); ++ _1 = GeneratorState::::Complete(_6); ++ discriminant((*_7)) = 1; + goto -> bb1; + } +