use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts};
use rustc_middle::ty::{self, adjustment::PointerCast, Instance, InstanceDef, Ty, TyCtxt};
use rustc_middle::ty::{Binder, TraitPredicate, TraitRef};
-use rustc_mir_dataflow::impls::MaybeMutBorrowedLocals;
use rustc_mir_dataflow::{self, Analysis};
use rustc_span::{sym, Span, Symbol};
use rustc_trait_selection::traits::error_reporting::InferCtxtExt;
use std::ops::Deref;
use super::ops::{self, NonConstOp, Status};
-use super::qualifs::{self, CustomEq, HasMutInterior, NeedsNonConstDrop};
+use super::qualifs::{self, CustomEq, HasMutInterior, NeedsDrop, NeedsNonConstDrop};
use super::resolver::FlowSensitiveAnalysis;
-use super::{is_lang_panic_fn, is_lang_special_const_fn, ConstCx, Qualif};
+use super::{ConstCx, Qualif};
use crate::const_eval::is_unstable_const_fn;
-// We are using `MaybeMutBorrowedLocals` as a proxy for whether an item may have been mutated
-// through a pointer prior to the given point. This is okay even though `MaybeMutBorrowedLocals`
-// kills locals upon `StorageDead` because a local will never be used after a `StorageDead`.
-type IndirectlyMutableResults<'mir, 'tcx> =
- rustc_mir_dataflow::ResultsCursor<'mir, 'tcx, MaybeMutBorrowedLocals<'mir, 'tcx>>;
-
type QualifResults<'mir, 'tcx, Q> =
rustc_mir_dataflow::ResultsCursor<'mir, 'tcx, FlowSensitiveAnalysis<'mir, 'mir, 'tcx, Q>>;
#[derive(Default)]
pub struct Qualifs<'mir, 'tcx> {
has_mut_interior: Option<QualifResults<'mir, 'tcx, HasMutInterior>>,
- needs_drop: Option<QualifResults<'mir, 'tcx, NeedsNonConstDrop>>,
- indirectly_mutable: Option<IndirectlyMutableResults<'mir, 'tcx>>,
+ needs_drop: Option<QualifResults<'mir, 'tcx, NeedsDrop>>,
+ needs_non_const_drop: Option<QualifResults<'mir, 'tcx, NeedsNonConstDrop>>,
}
impl Qualifs<'mir, 'tcx> {
- pub fn indirectly_mutable(
+ /// Returns `true` if `local` is `NeedsDrop` at the given `Location`.
+ ///
+ /// Only updates the cursor if absolutely necessary
+ pub fn needs_drop(
&mut self,
ccx: &'mir ConstCx<'mir, 'tcx>,
local: Local,
location: Location,
) -> bool {
- let indirectly_mutable = self.indirectly_mutable.get_or_insert_with(|| {
- let ConstCx { tcx, body, param_env, .. } = *ccx;
-
- // We can use `unsound_ignore_borrow_on_drop` here because custom drop impls are not
- // allowed in a const.
- //
- // FIXME(ecstaticmorse): Someday we want to allow custom drop impls. How do we do this
- // without breaking stable code?
- MaybeMutBorrowedLocals::mut_borrows_only(tcx, &body, param_env)
- .unsound_ignore_borrow_on_drop()
+ let ty = ccx.body.local_decls[local].ty;
+ if !NeedsDrop::in_any_value_of_ty(ccx, ty) {
+ return false;
+ }
+
+ let needs_drop = self.needs_drop.get_or_insert_with(|| {
+ let ConstCx { tcx, body, .. } = *ccx;
+
+ FlowSensitiveAnalysis::new(NeedsDrop, ccx)
.into_engine(tcx, &body)
- .pass_name("const_qualification")
.iterate_to_fixpoint()
.into_results_cursor(&body)
});
- indirectly_mutable.seek_before_primary_effect(location);
- indirectly_mutable.get().contains(local)
+ needs_drop.seek_before_primary_effect(location);
+ needs_drop.get().contains(local)
}
- /// Returns `true` if `local` is `NeedsDrop` at the given `Location`.
+ /// Returns `true` if `local` is `NeedsNonConstDrop` at the given `Location`.
///
/// Only updates the cursor if absolutely necessary
- pub fn needs_drop(
+ pub fn needs_non_const_drop(
&mut self,
ccx: &'mir ConstCx<'mir, 'tcx>,
local: Local,
return false;
}
- let needs_drop = self.needs_drop.get_or_insert_with(|| {
+ let needs_non_const_drop = self.needs_non_const_drop.get_or_insert_with(|| {
let ConstCx { tcx, body, .. } = *ccx;
FlowSensitiveAnalysis::new(NeedsNonConstDrop, ccx)
.into_results_cursor(&body)
});
- needs_drop.seek_before_primary_effect(location);
- needs_drop.get().contains(local) || self.indirectly_mutable(ccx, local, location)
+ needs_non_const_drop.seek_before_primary_effect(location);
+ needs_non_const_drop.get().contains(local)
}
/// Returns `true` if `local` is `HasMutInterior` at the given `Location`.
});
has_mut_interior.seek_before_primary_effect(location);
- has_mut_interior.get().contains(local) || self.indirectly_mutable(ccx, local, location)
+ has_mut_interior.get().contains(local)
}
fn in_return_place(
.into_results_cursor(&ccx.body);
cursor.seek_after_primary_effect(return_loc);
- cursor.contains(RETURN_PLACE)
+ cursor.get().contains(RETURN_PLACE)
}
};
ConstQualifs {
needs_drop: self.needs_drop(ccx, RETURN_PLACE, return_loc),
+ needs_non_const_drop: self.needs_non_const_drop(ccx, RETURN_PLACE, return_loc),
has_mut_interior: self.has_mut_interior(ccx, RETURN_PLACE, return_loc),
custom_eq,
error_occured,
Binder::dummy(TraitPredicate {
trait_ref,
constness: ty::BoundConstness::ConstIfConst,
+ polarity: ty::ImplPolarity::Positive,
}),
);
}
// At this point, we are calling a function, `callee`, whose `DefId` is known...
- if is_lang_special_const_fn(tcx, callee) {
- // `begin_panic` and `panic_display` are generic functions that accept
- // types other than str. Check to enforce that only str can be used in
- // const-eval.
-
- // const-eval of the `begin_panic` fn assumes the argument is `&str`
- if Some(callee) == tcx.lang_items().begin_panic_fn() {
- match args[0].ty(&self.ccx.body.local_decls, tcx).kind() {
- ty::Ref(_, ty, _) if ty.is_str() => (),
- _ => self.check_op(ops::PanicNonStr),
- }
- }
- // const-eval of the `panic_display` fn assumes the argument is `&&str`
- if Some(callee) == tcx.lang_items().panic_display() {
- match args[0].ty(&self.ccx.body.local_decls, tcx).kind() {
- ty::Ref(_, ty, _) if matches!(ty.kind(), ty::Ref(_, ty, _) if ty.is_str()) =>
- {}
- _ => self.check_op(ops::PanicNonStr),
- }
+ // `begin_panic` and `panic_display` are generic functions that accept
+ // types other than str. Check to enforce that only str can be used in
+ // const-eval.
+
+ // const-eval of the `begin_panic` fn assumes the argument is `&str`
+ if Some(callee) == tcx.lang_items().begin_panic_fn() {
+ match args[0].ty(&self.ccx.body.local_decls, tcx).kind() {
+ ty::Ref(_, ty, _) if ty.is_str() => return,
+ _ => self.check_op(ops::PanicNonStr),
}
+ }
- if is_lang_panic_fn(tcx, callee) {
- // run stability check on non-panic special const fns.
- return;
+ // const-eval of the `panic_display` fn assumes the argument is `&&str`
+ if Some(callee) == tcx.lang_items().panic_display() {
+ match args[0].ty(&self.ccx.body.local_decls, tcx).kind() {
+ ty::Ref(_, ty, _) if matches!(ty.kind(), ty::Ref(_, ty, _) if ty.is_str()) =>
+ {
+ return;
+ }
+ _ => self.check_op(ops::PanicNonStr),
}
}
}
// Forbid all `Drop` terminators unless the place being dropped is a local with no
- // projections that cannot be `NeedsDrop`.
+ // projections that cannot be `NeedsNonConstDrop`.
TerminatorKind::Drop { place: dropped_place, .. }
| TerminatorKind::DropAndReplace { place: dropped_place, .. } => {
// If we are checking live drops after drop-elaboration, don't emit duplicate
return;
}
- let needs_drop = if let Some(local) = dropped_place.as_local() {
+ let needs_non_const_drop = if let Some(local) = dropped_place.as_local() {
// Use the span where the local was declared as the span of the drop error.
err_span = self.body.local_decls[local].source_info.span;
- self.qualifs.needs_drop(self.ccx, local, location)
+ self.qualifs.needs_non_const_drop(self.ccx, local, location)
} else {
true
};
- if needs_drop {
+ if needs_non_const_drop {
self.check_op_spanned(
ops::LiveDrop { dropped_at: Some(terminator.source_info.span) },
err_span,
projects / rust.git / blobdiff