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use rustc::hir;
use rustc::mir::ProjectionElem;
use rustc::mir::{Local, Mir, Place, Mutability};
use rustc::ty::{self, TyCtxt};
use borrow_check::borrow_set::LocalsStateAtExit;
crate trait PlaceExt<'tcx> {
fn ignore_borrow(
&self,
tcx: TyCtxt<'_, '_, 'tcx>,
mir: &Mir<'tcx>,
locals_state_at_exit: &LocalsStateAtExit,
) -> bool;
fn root_local(&self) -> Option<Local>;
}
impl<'tcx> PlaceExt<'tcx> for Place<'tcx> {
fn ignore_borrow(
&self,
tcx: TyCtxt<'_, '_, 'tcx>,
mir: &Mir<'tcx>,
locals_state_at_exit: &LocalsStateAtExit,
) -> bool {
match self {
Place::Promoted(_) => false,
Place::Local(index) => {
match locals_state_at_exit {
LocalsStateAtExit::AllAreInvalidated => false,
LocalsStateAtExit::SomeAreInvalidated { has_storage_dead_or_moved } => {
let ignore = !has_storage_dead_or_moved.contains(*index) &&
mir.local_decls[*index].mutability == Mutability::Not;
debug!("ignore_borrow: local {:?} => {:?}", index, ignore);
ignore
}
}
}
Place::Static(static_) => {
tcx.is_static(static_.def_id) == Some(hir::Mutability::MutMutable)
}
Place::Projection(proj) => match proj.elem {
ProjectionElem::Field(..)
| ProjectionElem::Downcast(..)
| ProjectionElem::Subslice { .. }
| ProjectionElem::ConstantIndex { .. }
| ProjectionElem::Index(_) => proj.base.ignore_borrow(
tcx, mir, locals_state_at_exit),
ProjectionElem::Deref => {
let ty = proj.base.ty(mir, tcx).to_ty(tcx);
match ty.sty {
ty::RawPtr(..) | ty::Ref(_, _, hir::MutImmutable) => true,
_ => proj.base.ignore_borrow(tcx, mir, locals_state_at_exit),
}
}
},
}
}
fn root_local(&self) -> Option<Local> {
let mut p = self;
loop {
match p {
Place::Projection(pi) => p = &pi.base,
Place::Promoted(_) |
Place::Static(_) => return None,
Place::Local(l) => return Some(*l),
}
}
}
}