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treat generator fields like unions

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This commit is contained in:
Ralf Jung 2018-11-20 16:19:24 +01:00
parent 7f1077700c
commit 6befe6784f
1 changed files with 22 additions and 2 deletions
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24
src/librustc_mir/interpret/visitor.rs
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@ -158,7 +158,9 @@ macro_rules! make_value_visitor {
) -> EvalResult<'tcx> {
self.walk_aggregate(v, fields)
}
/// Called each time we recurse down to a field, passing in old and new value.
/// Called each time we recurse down to a field of a "product-like" aggregate
/// (structs, tuples, arrays and the like, but not enums), passing in old and new value.
/// This gives the visitor the chance to track the stack of nested fields that
/// we are descending through.
#[inline(always)]
@ -171,6 +173,19 @@ macro_rules! make_value_visitor {
self.visit_value(new_val)
}
/// Called for recursing into the field of a generator. These are not known to be
/// initialized, so we treat them like unions.
#[inline(always)]
fn visit_generator_field(
&mut self,
_old_val: Self::V,
_field: usize,
new_val: Self::V,
) -> EvalResult<'tcx> {
self.visit_union(new_val)
}
/// Called when recursing into an enum variant.
#[inline(always)]
fn visit_variant(
&mut self,
@ -300,7 +315,12 @@ macro_rules! make_value_visitor {
match v.layout().ty.sty {
ty::Generator(..) => {
let field = v.project_field(self.ecx(), 0)?;
self.visit_aggregate(v, std::iter::once(Ok(field)))
self.visit_aggregate(v, std::iter::once(Ok(field)))?;
for i in 1..offsets.len() {
let field = v.project_field(self.ecx(), i as u64)?;
self.visit_generator_field(v, i, field)?;
}
Ok(())
}
_ => {
// FIXME: We collect in a vec because otherwise there are lifetime