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Migrate from recursion to iterate on qualify consts visitor impl #61023

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Merged
merged 1 commit into from
May 23, 2019
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Migrate from recursion to iterate on qualify consts visitor impl #61023

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94 changes: 48 additions & 46 deletions src/librustc_mir/transform/qualify_consts.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -930,58 +930,60 @@ impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
context: PlaceContext,
location: Location) {
debug!("visit_place: place={:?} context={:?} location={:?}", place, context, location);
self.super_place(place, context, location);
match *place {
Place::Base(PlaceBase::Local(_)) => {}
Place::Base(PlaceBase::Static(box Static{ kind: StaticKind::Promoted(_), .. })) => {
unreachable!()
}
Place::Base(PlaceBase::Static(box Static{ kind: StaticKind::Static(def_id), .. })) => {
if self.tcx
.get_attrs(def_id)
.iter()
.any(|attr| attr.check_name(sym::thread_local)) {
if self.mode != Mode::Fn {
span_err!(self.tcx.sess, self.span, E0625,
"thread-local statics cannot be \
accessed at compile-time");
}
return;
place.iterate(|place_base, place_projections| {
match place_base {
PlaceBase::Local(_) => {}
PlaceBase::Static(box Static{ kind: StaticKind::Promoted(_), .. }) => {
unreachable!()
}
PlaceBase::Static(box Static{ kind: StaticKind::Static(def_id), .. }) => {
if self.tcx
.get_attrs(*def_id)
.iter()
.any(|attr| attr.check_name(sym::thread_local)) {
if self.mode != Mode::Fn {
span_err!(self.tcx.sess, self.span, E0625,
"thread-local statics cannot be \
accessed at compile-time");
}
return;
}

// Only allow statics (not consts) to refer to other statics.
if self.mode == Mode::Static || self.mode == Mode::StaticMut {
if self.mode == Mode::Static && context.is_mutating_use() {
// this is not strictly necessary as miri will also bail out
// For interior mutability we can't really catch this statically as that
// goes through raw pointers and intermediate temporaries, so miri has
// to catch this anyway
self.tcx.sess.span_err(
self.span,
"cannot mutate statics in the initializer of another static",
);
// Only allow statics (not consts) to refer to other statics.
if self.mode == Mode::Static || self.mode == Mode::StaticMut {
if self.mode == Mode::Static && context.is_mutating_use() {
// this is not strictly necessary as miri will also bail out
// For interior mutability we can't really catch this statically as that
// goes through raw pointers and intermediate temporaries, so miri has
// to catch this anyway
self.tcx.sess.span_err(
self.span,
"cannot mutate statics in the initializer of another static",
);
}
return;
}
return;
}
unleash_miri!(self);
unleash_miri!(self);

if self.mode != Mode::Fn {
let mut err = struct_span_err!(self.tcx.sess, self.span, E0013,
"{}s cannot refer to statics, use \
a constant instead", self.mode);
if self.tcx.sess.teach(&err.get_code().unwrap()) {
err.note(
"Static and const variables can refer to other const variables. But a \
const variable cannot refer to a static variable."
);
err.help(
"To fix this, the value can be extracted as a const and then used."
);
if self.mode != Mode::Fn {
let mut err = struct_span_err!(self.tcx.sess, self.span, E0013,
"{}s cannot refer to statics, use \
a constant instead", self.mode);
if self.tcx.sess.teach(&err.get_code().unwrap()) {
err.note(
"Static and const variables can refer to other const variables. \
But a const variable cannot refer to a static variable."
);
err.help(
"To fix this, the value can be extracted as a const and then used."
);
}
err.emit()
}
err.emit()
}
}
Place::Projection(ref proj) => {

for proj in place_projections {
match proj.elem {
ProjectionElem::Deref => {
if context.is_mutating_use() {
Expand Down Expand Up @@ -1041,7 +1043,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
}
}
}
}
});
}

fn visit_operand(&mut self, operand: &Operand<'tcx>, location: Location) {
Expand Down