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use rustc_data_structures::undo_log::UndoLogs;
use rustc_hir::OpaqueTyOrigin;
use rustc_middle::ty::{self, OpaqueHiddenType, OpaqueTypeKey, Ty};
use rustc_span::DUMMY_SP;
use crate::infer::{InferCtxtUndoLogs, UndoLog};
use super::{OpaqueTypeDecl, OpaqueTypeMap};
#[derive(Default, Debug, Clone)]
pub struct OpaqueTypeStorage<'tcx> {
/// Opaque types found in explicit return types and their
/// associated fresh inference variable. Writeback resolves these
/// variables to get the concrete type, which can be used to
/// 'de-opaque' OpaqueTypeDecl, after typeck is done with all functions.
pub opaque_types: OpaqueTypeMap<'tcx>,
}
impl<'tcx> OpaqueTypeStorage<'tcx> {
#[instrument(level = "debug")]
pub(crate) fn remove(&mut self, key: OpaqueTypeKey<'tcx>, idx: Option<OpaqueHiddenType<'tcx>>) {
if let Some(idx) = idx {
self.opaque_types.get_mut(&key).unwrap().hidden_type = idx;
} else {
match self.opaque_types.remove(&key) {
None => bug!("reverted opaque type inference that was never registered: {:?}", key),
Some(_) => {}
}
}
}
#[inline]
pub(crate) fn with_log<'a>(
&'a mut self,
undo_log: &'a mut InferCtxtUndoLogs<'tcx>,
) -> OpaqueTypeTable<'a, 'tcx> {
OpaqueTypeTable { storage: self, undo_log }
}
}
impl<'tcx> Drop for OpaqueTypeStorage<'tcx> {
fn drop(&mut self) {
if !self.opaque_types.is_empty() {
ty::tls::with(|tcx| {
tcx.sess.delay_span_bug(DUMMY_SP, &format!("{:?}", self.opaque_types))
});
}
}
}
pub struct OpaqueTypeTable<'a, 'tcx> {
storage: &'a mut OpaqueTypeStorage<'tcx>,
undo_log: &'a mut InferCtxtUndoLogs<'tcx>,
}
impl<'a, 'tcx> OpaqueTypeTable<'a, 'tcx> {
#[instrument(skip(self), level = "debug")]
pub(crate) fn register(
&mut self,
key: OpaqueTypeKey<'tcx>,
hidden_type: OpaqueHiddenType<'tcx>,
origin: OpaqueTyOrigin,
) -> Option<Ty<'tcx>> {
if let Some(decl) = self.storage.opaque_types.get_mut(&key) {
let prev = std::mem::replace(&mut decl.hidden_type, hidden_type);
self.undo_log.push(UndoLog::OpaqueTypes(key, Some(prev)));
return Some(prev.ty);
}
let decl = OpaqueTypeDecl { hidden_type, origin };
self.storage.opaque_types.insert(key, decl);
self.undo_log.push(UndoLog::OpaqueTypes(key, None));
None
}
}
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