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Add variance constraints for const params

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This commit is contained in:
Dominik Stolz 2021-10-07 23:14:33 +02:00
parent ca8078d7b2
commit 8b141a24d0
1 changed files with 25 additions and 5 deletions
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30
compiler/rustc_typeck/src/variance/constraints.rs
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@ -223,8 +223,8 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
self.add_constraints_from_region(current, lt, variance_i)
}
GenericArgKind::Type(ty) => self.add_constraints_from_ty(current, ty, variance_i),
GenericArgKind::Const(_) => {
// Consts impose no constraints.
GenericArgKind::Const(val) => {
self.add_constraints_from_const(current, val, variance_i)
}
}
}
@ -263,7 +263,8 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
self.add_constraints_from_mt(current, &ty::TypeAndMut { ty, mutbl }, variance);
}
ty::Array(typ, _) => {
ty::Array(typ, len) => {
self.add_constraints_from_const(current, len, variance);
self.add_constraints_from_ty(current, typ, variance);
}
@ -385,13 +386,32 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
self.add_constraints_from_region(current, lt, variance_i)
}
GenericArgKind::Type(ty) => self.add_constraints_from_ty(current, ty, variance_i),
GenericArgKind::Const(_) => {
// Consts impose no constraints.
GenericArgKind::Const(val) => {
self.add_constraints_from_const(current, val, variance)
}
}
}
}
/// Adds constraints appropriate for a const expression `val`
/// in a context with ambient variance `variance`
fn add_constraints_from_const(
&mut self,
current: &CurrentItem,
val: &ty::Const<'tcx>,
variance: VarianceTermPtr<'a>,
) {
debug!("add_constraints_from_const(val={:?}, variance={:?})", val, variance);
match &val.val {
ty::ConstKind::Unevaluated(uv) => {
let substs = uv.substs(self.tcx());
self.add_constraints_from_invariant_substs(current, substs, variance);
}
_ => {}
}
}
/// Adds constraints appropriate for a function with signature
/// `sig` appearing in a context with ambient variance `variance`
fn add_constraints_from_sig(