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use rustc_middle::mir::visit::Visitor;
use rustc_middle::mir::{Constant, ConstantKind, Location};
use rustc_middle::ty::ConstKind;
pub struct RequiredConstsVisitor<'a, 'tcx> {
required_consts: &'a mut Vec<Constant<'tcx>>,
}
impl<'a, 'tcx> RequiredConstsVisitor<'a, 'tcx> {
pub fn new(required_consts: &'a mut Vec<Constant<'tcx>>) -> Self {
RequiredConstsVisitor { required_consts }
}
}
impl<'tcx> Visitor<'tcx> for RequiredConstsVisitor<'_, 'tcx> {
fn visit_constant(&mut self, constant: &Constant<'tcx>, _: Location) {
let literal = constant.literal;
match literal {
ConstantKind::Ty(c) => match c.kind() {
ConstKind::Param(_) => {}
_ => bug!("only ConstKind::Param should be encountered here, got {:#?}", c),
},
ConstantKind::Unevaluated(..) => self.required_consts.push(*constant),
ConstantKind::Val(..) => {}
}
}
}