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Fixed interior mutable references causing a mark

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The mutability system now checks where derefs go through borrows in the
loan chain, and can correctly detect mutable borrows inside structs and
tuples.
This commit is contained in:
Isaac van Bakel 2017-08-01 15:06:14 +01:00
parent 400075d9d9
commit 8e4c9e4e9d
1 changed files with 32 additions and 25 deletions
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57
src/librustc_borrowck/borrowck/gather_loans/mod.rs
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@ -431,38 +431,45 @@ impl<'a, 'tcx> GatherLoanCtxt<'a, 'tcx> {
// }
// }
}
pub fn mark_loan_path_as_mutated(&self, loan_path: &LoanPath) {
//! For mutable loans of content whose mutability derives
//! from a local variable, mark the mutability decl as necessary.
match loan_path.kind {
LpVar(local_id) |
LpUpvar(ty::UpvarId{ var_id: local_id, closure_expr_id: _ }) => {
self.tcx().used_mut_nodes.borrow_mut().insert(local_id);
}
LpExtend(ref base, mc::McInherited, LpDeref(pointer_kind)) |
LpExtend(ref base, mc::McDeclared, LpDeref(pointer_kind)) => {
match base.kind {
LpVar(_) if pointer_kind != mc::Unique => {
// If you mutate the inside of a ref var, the var itself
// is not used mutably [Issue #25049]
// Unless it's a Box! (mc::Unique)
}
_ => {
self.mark_loan_path_as_mutated(&base);
let mut wrapped_path = Some(loan_path);
let mut through_borrow = false;
while let Some(current_path) = wrapped_path {
wrapped_path = match current_path.kind {
LpVar(local_id) => {
if !through_borrow {
self.tcx().used_mut_nodes.borrow_mut().insert(local_id);
}
None
}
}
LpDowncast(ref base, _) |
LpExtend(ref base, mc::McInherited, _) |
LpExtend(ref base, mc::McDeclared, _) => {
self.mark_loan_path_as_mutated(&base);
}
LpExtend(_, mc::McImmutable, _) => {
// Nothing to do.
}
LpUpvar(ty::UpvarId{ var_id: local_id, closure_expr_id: _ }) => {
self.tcx().used_mut_nodes.borrow_mut().insert(local_id);
None
}
LpExtend(ref base, mc::McInherited, LpDeref(pointer_kind)) |
LpExtend(ref base, mc::McDeclared, LpDeref(pointer_kind)) => {
if pointer_kind != mc::Unique {
through_borrow = true;
}
Some(base)
}
LpDowncast(ref base, _) |
LpExtend(ref base, mc::McInherited, _) |
LpExtend(ref base, mc::McDeclared, _) => {
Some(base)
}
LpExtend(_, mc::McImmutable, _) => {
// Nothing to do.
None
}
}
}
}
pub fn compute_gen_scope(&self,