subtyping_projections

This commit is contained in:
ouz-a 2023-08-16 08:43:30 +03:00
parent 177091258c
commit 3148e6a993
28 changed files with 431 additions and 5 deletions

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@ -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),

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@ -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 {
@ -317,6 +318,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
PlaceRef { local, projection: [proj_base @ .., elem] } => match elem {
ProjectionElem::Deref
| ProjectionElem::Index(..)
| ProjectionElem::Subtype(..)
| ProjectionElem::ConstantIndex { .. }
| ProjectionElem::Subslice { .. } => {
PlaceRef { local, projection: proj_base }.ty(self.body, self.infcx.tcx)

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@ -159,6 +159,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
[
..,
ProjectionElem::Index(_)
| ProjectionElem::Subtype(_)
| ProjectionElem::ConstantIndex { .. }
| ProjectionElem::OpaqueCast { .. }
| ProjectionElem::Subslice { .. }

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@ -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);

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@ -243,6 +243,7 @@ fn place_components_conflict<'tcx>(
}
(ProjectionElem::Deref, _, Deep)
| (ProjectionElem::Subtype(_), _, _)
| (ProjectionElem::Deref, _, AccessDepth::Drop)
| (ProjectionElem::Field { .. }, _, _)
| (ProjectionElem::Index { .. }, _, _)
@ -359,6 +360,7 @@ fn place_projection_conflict<'tcx>(
(
ProjectionElem::Index(..),
ProjectionElem::Index(..)
| ProjectionElem::Subtype(..)
| ProjectionElem::ConstantIndex { .. }
| ProjectionElem::Subslice { .. },
)
@ -503,6 +505,7 @@ fn place_projection_conflict<'tcx>(
debug!("place_element_conflict: DISJOINT-OR-EQ-SLICE-SUBSLICES");
Overlap::EqualOrDisjoint
}
(ProjectionElem::Subtype(_), _) => Overlap::EqualOrDisjoint,
(
ProjectionElem::Deref
| ProjectionElem::Field(..)

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@ -89,6 +89,7 @@ impl<'cx, 'tcx> Iterator for Prefixes<'cx, 'tcx> {
cursor = cursor_base;
continue 'cursor;
}
ProjectionElem::Subtype(..) => continue 'cursor,
ProjectionElem::Deref => {
// (handled below)
}

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@ -621,6 +621,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
span_mirbug_and_err!(self, place, "deref of non-pointer {:?}", base_ty)
}))
}
ProjectionElem::Subtype(ty) => PlaceTy::from_ty(ty),
ProjectionElem::Index(i) => {
let index_ty = Place::from(i).ty(self.body(), tcx).ty;
if index_ty != tcx.types.usize {
@ -2556,6 +2557,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
}
}
ProjectionElem::Field(..)
| ProjectionElem::Subtype(..)
| ProjectionElem::Downcast(..)
| ProjectionElem::OpaqueCast(..)
| ProjectionElem::Index(..)

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@ -872,6 +872,9 @@ pub(crate) fn codegen_place<'tcx>(
for elem in place.projection {
match elem {
PlaceElem::Subtype(_) => {
continue;
}
PlaceElem::Deref => {
cplace = cplace.place_deref(fx);
}

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@ -499,6 +499,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
subslice
}
mir::ProjectionElem::Downcast(_, v) => cg_base.project_downcast(bx, v),
mir::ProjectionElem::Subtype(_) => continue,
};
}
debug!("codegen_place(place={:?}) => {:?}", place_ref, cg_base);

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@ -665,6 +665,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
let mut op = self.local_to_op(self.frame(), mir_place.local, layout)?;
// Using `try_fold` turned out to be bad for performance, hence the loop.
for elem in mir_place.projection.iter() {
if elem.is_subtype() {
continue;
}
op = self.project(&op, elem)?
}

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@ -332,6 +332,7 @@ where
self.project_constant_index(base, offset, min_length, from_end)?
}
Subslice { from, to, from_end } => self.project_subslice(base, from, to, from_end)?,
Subtype(ty) => base.transmute(self.layout_of(ty)?, self)?,
})
}
}

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@ -664,6 +664,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
| ProjectionElem::Downcast(..)
| ProjectionElem::OpaqueCast(..)
| ProjectionElem::Subslice { .. }
| ProjectionElem::Subtype(..)
| ProjectionElem::Field(..)
| ProjectionElem::Index(_) => {}
}

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@ -306,6 +306,7 @@ where
ProjectionElem::Index(index) if in_local(index) => return true,
ProjectionElem::Deref
| ProjectionElem::Subtype(_)
| ProjectionElem::Field(_, _)
| ProjectionElem::OpaqueCast(_)
| ProjectionElem::ConstantIndex { .. }

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@ -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;

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@ -608,6 +608,29 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
fn visit_operand(&mut self, operand: &Operand<'tcx>, location: Location) {
match operand {
Operand::Copy(place) | Operand::Move(place) => {
if let Some(stmt) = self.body.stmt_at(location).left() {
match &stmt.kind {
StatementKind::Assign(box (lval, rvalue)) => {
let place_ty = place.ty(&self.body.local_decls, self.tcx).ty;
let lval_ty = lval.ty(&self.body.local_decls, self.tcx).ty;
if !place.is_subtype()
&& place_ty != lval_ty
&& rvalue.ty(&self.body.local_decls, self.tcx) != lval_ty
&& (rvalue.ty(&self.body.local_decls, self.tcx).is_closure()
!= lval_ty.is_closure())
{
self.fail(location, format!("Subtyping is not allowed between types {place_ty:#?} and {lval_ty:#?}"))
}
}
_ => (),
}
}
}
_ => (),
}
// This check is somewhat expensive, so only run it when -Zvalidate-mir is passed.
if self.tcx.sess.opts.unstable_opts.validate_mir
&& self.mir_phase < MirPhase::Runtime(RuntimePhase::Initial)
@ -1088,6 +1111,7 @@ 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,

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@ -1075,6 +1075,8 @@ pub enum ProjectionElem<V, T> {
/// Like an explicit cast from an opaque type to a concrete type, but without
/// requiring an intermediate variable.
OpaqueCast(T),
Subtype(T),
}
/// Alias for projections as they appear in places, where the base is a place

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@ -111,6 +111,7 @@ impl<'tcx> PlaceTy<'tcx> {
}
ProjectionElem::Field(f, fty) => PlaceTy::from_ty(handle_field(&self, f, fty)),
ProjectionElem::OpaqueCast(ty) => PlaceTy::from_ty(handle_opaque_cast(&self, ty)),
ProjectionElem::Subtype(_) => PlaceTy::from_ty(self.ty),
};
debug!("projection_ty self: {:?} elem: {:?} yields: {:?}", self, elem, answer);
answer

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@ -1110,6 +1110,7 @@ macro_rules! visit_place_fns {
if ty != new_ty { Some(PlaceElem::OpaqueCast(new_ty)) } else { None }
}
PlaceElem::Deref
| PlaceElem::Subtype { .. }
| PlaceElem::ConstantIndex { .. }
| PlaceElem::Subslice { .. }
| PlaceElem::Downcast(..) => None,
@ -1175,7 +1176,9 @@ 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) => {

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@ -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 { .. } => (),
}

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@ -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()),
}
}
}

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@ -112,6 +112,9 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
let mut union_path = None;
for (place_ref, elem) in data.rev_lookup.un_derefer.iter_projections(place.as_ref()) {
if elem.is_subtype() {
continue;
}
let body = self.builder.body;
let tcx = self.builder.tcx;
let place_ty = place_ref.ty(body, tcx).ty;

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@ -0,0 +1,57 @@
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 SubTypeCheker<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
patcher: MirPatch<'tcx>,
local_decls: &'a IndexVec<Local, LocalDecl<'tcx>>,
}
impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeCheker<'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 place_ty = place.ty(self.local_decls, self.tcx);
let rval_ty = rvalue.ty(self.local_decls, self.tcx);
if place_ty.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).project_deeper(&[ProjectionElem::Subtype(place_ty.ty)], self.tcx);
self.patcher.add_assign(location, new_place, rvalue.clone());
let new_rval = Rvalue::Use(Operand::Move(new_place));
*rvalue = new_rval;
}
}
}
pub fn subtype_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
let patch = MirPatch::new(body);
let mut checker = SubTypeCheker { 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);
}
}

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@ -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,

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@ -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(_) => {},
}
}

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@ -0,0 +1,262 @@
- // MIR for `main` before Subtyper
+ // MIR for `main` after Subtyper
| User Type Annotations
| 0: user_ty: Canonical { value: TypeOf(DefId(5:284 ~ alloc[be7e]::boxed::{impl#0}::new), UserArgs { args: [^0], user_self_ty: Some(UserSelfTy { impl_def_id: DefId(5:282 ~ alloc[be7e]::boxed::{impl#0}), self_ty: std::boxed::Box<^1, ^2> }) }), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/mir_subtyping.rs:34:10: 34:18, inferred_ty: fn(Foo<fn(&u8)>) -> std::boxed::Box<Foo<fn(&u8)>> {std::boxed::Box::<Foo<fn(&u8)>>::new}
| 1: user_ty: Canonical { value: Ty(fn(&'static u8)), max_universe: U0, variables: [] }, span: $DIR/mir_subtyping.rs:34:23: 34:48, inferred_ty: fn(&u8)
| 2: user_ty: Canonical { value: Ty(std::boxed::Box<dyn GetInner<Assoc = std::string::String>>), max_universe: U1, variables: [CanonicalVarInfo { kind: Region(U1) }] }, span: $DIR/mir_subtyping.rs:34:10: 34:87, inferred_ty: std::boxed::Box<dyn GetInner<Assoc = std::string::String>>
| 3: user_ty: Canonical { value: TypeOf(DefId(5:284 ~ alloc[be7e]::boxed::{impl#0}::new), UserArgs { args: [^0], user_self_ty: Some(UserSelfTy { impl_def_id: DefId(5:282 ~ alloc[be7e]::boxed::{impl#0}), self_ty: std::boxed::Box<^1, ^2> }) }), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/mir_subtyping.rs:35:10: 35:18, inferred_ty: fn(Foo<for<'a> fn(&'a u8)>) -> std::boxed::Box<Foo<for<'a> fn(&'a u8)>> {std::boxed::Box::<Foo<for<'a> fn(&'a u8)>>::new}
| 4: user_ty: Canonical { value: Ty(std::boxed::Box<dyn GetInner<Assoc = [usize; 3]>>), max_universe: U1, variables: [CanonicalVarInfo { kind: Region(U1) }] }, span: $DIR/mir_subtyping.rs:35:10: 35:83, inferred_ty: std::boxed::Box<dyn GetInner<Assoc = [usize; 3]>>
| 5: user_ty: Canonical { value: TypeOf(DefId(5:284 ~ alloc[be7e]::boxed::{impl#0}::new), UserArgs { args: [^0], user_self_ty: Some(UserSelfTy { impl_def_id: DefId(5:282 ~ alloc[be7e]::boxed::{impl#0}), self_ty: std::boxed::Box<^1, ^2> }) }), max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }] }, span: $DIR/mir_subtyping.rs:37:20: 37:28, inferred_ty: fn(Foo<for<'a> fn(&'a u8)>) -> std::boxed::Box<Foo<for<'a> fn(&'a u8)>> {std::boxed::Box::<Foo<for<'a> fn(&'a u8)>>::new}
| 6: user_ty: Canonical { value: Ty(std::boxed::Box<Foo<fn(&'static u8)>>), max_universe: U0, variables: [] }, span: $DIR/mir_subtyping.rs:38:20: 38:57, inferred_ty: std::boxed::Box<Foo<fn(&u8)>>
| 7: user_ty: Canonical { value: Ty(std::boxed::Box<dyn GetInner<Assoc = std::string::String>>), max_universe: U1, variables: [CanonicalVarInfo { kind: Region(U1) }] }, span: $DIR/mir_subtyping.rs:39:19: 39:64, inferred_ty: std::boxed::Box<dyn GetInner<Assoc = std::string::String>>
|
fn main() -> () {
let mut _0: ();
let _1: Wrapper;
let mut _2: for<'a> fn(&'a u8);
let _3: ();
let mut _4: std::boxed::Box<dyn GetInner<Assoc = std::string::String>>;
let mut _5: std::boxed::Box<dyn GetInner<Assoc = std::string::String>>;
let mut _6: std::boxed::Box<Foo<fn(&u8)>>;
let mut _7: Foo<fn(&u8)>;
let mut _8: fn(&u8);
let mut _9: fn(&u8);
let _10: ();
let mut _11: std::boxed::Box<dyn GetInner<Assoc = [usize; 3]>>;
let mut _12: std::boxed::Box<dyn GetInner<Assoc = [usize; 3]>>;
let mut _13: std::boxed::Box<Foo<for<'a> fn(&'a u8)>>;
let mut _14: Foo<for<'a> fn(&'a u8)>;
let mut _15: for<'a> fn(&'a u8);
let mut _17: Foo<for<'a> fn(&'a u8)>;
let mut _18: for<'b> fn(&'b u8);
let mut _20: std::boxed::Box<Foo<fn(&u8)>>;
let mut _22: std::boxed::Box<dyn GetInner<Assoc = std::string::String>>;
let mut _23: std::boxed::Box<Foo<fn(&u8)>>;
let mut _25: &mut dyn GetInner<Assoc = std::string::String>;
let _26: ();
let mut _27: std::string::String;
+ let mut _28: std::boxed::Box<Foo<for<'a> fn(&'a u8)>>;
scope 1 {
debug wrapper => _1;
let _16: std::boxed::Box<Foo<for<'a> fn(&'a u8)>>;
scope 2 {
debug hr_fnptr => _16;
let _19: std::boxed::Box<Foo<fn(&u8)>>;
scope 3 {
debug lr_fnptr => _19;
let mut _21: std::boxed::Box<dyn GetInner<Assoc = std::string::String>>;
scope 4 {
debug any => _21;
let _24: std::string::String;
scope 5 {
debug evil_string => _24;
}
}
}
}
}
bb0: {
StorageLive(_1);
StorageLive(_2);
_2 = useful as for<'a> fn(&'a u8) (PointerCoercion(ReifyFnPointer));
_1 = Wrapper(move _2);
StorageDead(_2);
FakeRead(ForLet(None), _1);
StorageLive(_3);
StorageLive(_4);
StorageLive(_5);
StorageLive(_6);
StorageLive(_7);
StorageLive(_8);
StorageLive(_9);
_9 = useful as for<'a> fn(&'a u8) (PointerCoercion(ReifyFnPointer));
AscribeUserType(_9, o, UserTypeProjection { base: UserType(1), projs: [] });
_8 = _9;
_7 = Foo::<fn(&u8)>(move _8);
StorageDead(_8);
_6 = Box::<Foo<fn(&u8)>>::new(move _7) -> [return: bb1, unwind: bb28];
}
bb1: {
_5 = move _6 as std::boxed::Box<dyn GetInner<Assoc = std::string::String>> (PointerCoercion(Unsize));
drop(_6) -> [return: bb2, unwind: bb28];
}
bb2: {
StorageDead(_7);
StorageDead(_6);
AscribeUserType(_5, o, UserTypeProjection { base: UserType(2), projs: [] });
_4 = move _5;
_3 = std::mem::drop::<Box<dyn GetInner<Assoc = String>>>(move _4) -> [return: bb3, unwind: bb26];
}
bb3: {
StorageDead(_4);
drop(_5) -> [return: bb4, unwind: bb28];
}
bb4: {
StorageDead(_9);
StorageDead(_5);
StorageDead(_3);
StorageLive(_10);
StorageLive(_11);
StorageLive(_12);
StorageLive(_13);
StorageLive(_14);
StorageLive(_15);
_15 = useful as for<'a> fn(&'a u8) (PointerCoercion(ReifyFnPointer));
_14 = Foo::<for<'a> fn(&'a u8)>(move _15);
StorageDead(_15);
_13 = Box::<Foo<for<'a> fn(&'a u8)>>::new(move _14) -> [return: bb5, unwind: bb28];
}
bb5: {
_12 = move _13 as std::boxed::Box<dyn GetInner<Assoc = [usize; 3]>> (PointerCoercion(Unsize));
drop(_13) -> [return: bb6, unwind: bb28];
}
bb6: {
StorageDead(_14);
StorageDead(_13);
AscribeUserType(_12, o, UserTypeProjection { base: UserType(4), projs: [] });
_11 = move _12;
_10 = std::mem::drop::<Box<dyn GetInner<Assoc = [usize; 3]>>>(move _11) -> [return: bb7, unwind: bb24];
}
bb7: {
StorageDead(_11);
drop(_12) -> [return: bb8, unwind: bb28];
}
bb8: {
StorageDead(_12);
StorageDead(_10);
StorageLive(_16);
StorageLive(_17);
StorageLive(_18);
_18 = (_1.0: for<'b> fn(&'b u8));
_17 = Foo::<for<'a> fn(&'a u8)>(move _18);
StorageDead(_18);
_16 = Box::<Foo<for<'a> fn(&'a u8)>>::new(move _17) -> [return: bb9, unwind: bb28];
}
bb9: {
StorageDead(_17);
FakeRead(ForLet(None), _16);
StorageLive(_19);
StorageLive(_20);
- _20 = move _16;
+ _20 = move (_16 Subtyped as Box<Foo<fn(&u8)>>;
AscribeUserType(_20, o, UserTypeProjection { base: UserType(6), projs: [] });
_19 = move _20;
FakeRead(ForLet(None), _19);
drop(_20) -> [return: bb10, unwind: bb22];
}
bb10: {
StorageDead(_20);
StorageLive(_21);
StorageLive(_22);
StorageLive(_23);
_23 = move _19;
_22 = move _23 as std::boxed::Box<dyn GetInner<Assoc = std::string::String>> (PointerCoercion(Unsize));
drop(_23) -> [return: bb11, unwind: bb22];
}
bb11: {
StorageDead(_23);
AscribeUserType(_22, o, UserTypeProjection { base: UserType(7), projs: [] });
_21 = move _22;
FakeRead(ForLet(None), _21);
drop(_22) -> [return: bb12, unwind: bb21];
}
bb12: {
StorageDead(_22);
StorageLive(_24);
StorageLive(_25);
_25 = &mut (*_21);
_24 = <dyn GetInner<Assoc = String> as GetInner>::muahaha(move _25) -> [return: bb13, unwind: bb21];
}
bb13: {
StorageDead(_25);
FakeRead(ForLet(None), _24);
StorageLive(_26);
StorageLive(_27);
_27 = move _24;
_26 = std::mem::drop::<String>(move _27) -> [return: bb14, unwind: bb19];
}
bb14: {
StorageDead(_27);
StorageDead(_26);
_0 = const ();
drop(_24) -> [return: bb15, unwind: bb21];
}
bb15: {
StorageDead(_24);
drop(_21) -> [return: bb16, unwind: bb22];
}
bb16: {
StorageDead(_21);
drop(_19) -> [return: bb17, unwind: bb23];
}
bb17: {
StorageDead(_19);
drop(_16) -> [return: bb18, unwind: bb28];
}
bb18: {
StorageDead(_16);
StorageDead(_1);
return;
}
bb19 (cleanup): {
drop(_27) -> [return: bb20, unwind terminate];
}
bb20 (cleanup): {
drop(_24) -> [return: bb21, unwind terminate];
}
bb21 (cleanup): {
drop(_21) -> [return: bb22, unwind terminate];
}
bb22 (cleanup): {
drop(_19) -> [return: bb23, unwind terminate];
}
bb23 (cleanup): {
drop(_16) -> [return: bb28, unwind terminate];
}
bb24 (cleanup): {
drop(_11) -> [return: bb25, unwind terminate];
}
bb25 (cleanup): {
drop(_12) -> [return: bb28, unwind terminate];
}
bb26 (cleanup): {
drop(_4) -> [return: bb27, unwind terminate];
}
bb27 (cleanup): {
drop(_5) -> [return: bb28, unwind terminate];
}
bb28 (cleanup): {
resume;
}
}

View File

@ -0,0 +1,43 @@
// compile-flags: -Z mir-opt-level=0
// EMIT_MIR mir_subtyping.main.Subtyper.diff
#![allow(coherence_leak_check)]
struct Foo<T: 'static>(T);
fn useful<'a>(_: &'a u8) {}
pub struct Wrapper(for<'b> fn(&'b u8));
trait GetInner {
type Assoc;
fn muahaha(&mut self) -> Self::Assoc;
}
impl GetInner for Foo<fn(&'static u8)> {
type Assoc = String;
fn muahaha(&mut self) -> String {
panic!("cant do it boss")
}
}
impl GetInner for Foo<for<'a> fn(&'a u8)> {
type Assoc = [usize; 3];
fn muahaha(&mut self) -> [usize; 3] {
[100; 3]
}
}
fn main() {
let wrapper = Wrapper(useful);
drop(Box::new(Foo(useful as fn(&'static u8))) as Box<dyn GetInner<Assoc = String>>);
drop(Box::new(Foo(useful as fn(&u8))) as Box<dyn GetInner<Assoc = [usize; 3]>>);
let hr_fnptr = Box::new(Foo::<for<'a> fn(&'a u8)>(wrapper.0));
let lr_fnptr = hr_fnptr as Box<Foo<fn(&'static u8)>>;
let mut any = lr_fnptr as Box<dyn GetInner<Assoc = String>>;
let evil_string = any.muahaha();
drop(evil_string);
}

View File

@ -22,6 +22,7 @@ fn main() -> () {
let _24: i32;
let mut _26: *const i32;
let _27: ();
let mut _29: [closure@main::{closure#0}];
scope 1 {
debug x => _1;
let _3: &mut i32;
@ -105,7 +106,7 @@ fn main() -> () {
StorageLive(_14);
_14 = {closure@main::{closure#0}};
Retag(_14);
_13 = move _14 as for<'a> fn(&'a i32) -> &'a i32 (PointerCoercion(ClosureFnPointer(Normal)));
_13 = move (_14 Subtyped as for<'a> fn(&'a i32) -> &'a i32 as for<'a> fn(&'a i32) -> &'a i32 (PointerCoercion(ClosureFnPointer(Normal)));
StorageDead(_14);
StorageLive(_15);
StorageLive(_16);

View File

@ -22,6 +22,7 @@ fn main() -> () {
let _24: i32;
let mut _26: *const i32;
let _27: ();
let mut _29: [closure@main::{closure#0}];
scope 1 {
debug x => _1;
let _3: &mut i32;
@ -105,7 +106,7 @@ fn main() -> () {
StorageLive(_14);
_14 = {closure@main::{closure#0}};
Retag(_14);
_13 = move _14 as for<'a> fn(&'a i32) -> &'a i32 (PointerCoercion(ClosureFnPointer(Normal)));
_13 = move (_14 Subtyped as for<'a> fn(&'a i32) -> &'a i32 as for<'a> fn(&'a i32) -> &'a i32 (PointerCoercion(ClosureFnPointer(Normal)));
StorageDead(_14);
StorageLive(_15);
StorageLive(_16);