src/librustc_mir/monomorphize/mod.rs

   1 use rustc::traits;
   2 use rustc::ty::adjustment::CustomCoerceUnsized;
   3 use rustc::ty::{self, Ty, TyCtxt};
   4
   5 pub mod collector;
   6 pub mod partitioning;
   7
   8 pub fn custom_coerce_unsize_info<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
   9                                            source_ty: Ty<'tcx>,
  10                                            target_ty: Ty<'tcx>)
  11                                            -> CustomCoerceUnsized {
  12     let def_id = tcx.lang_items().coerce_unsized_trait().unwrap();
  13
  14     let trait_ref = ty::Binder::bind(ty::TraitRef {
  15         def_id: def_id,
  16         substs: tcx.mk_substs_trait(source_ty, &[target_ty.into()])
  17     });
  18
  19     match tcx.codegen_fulfill_obligation( (ty::ParamEnv::reveal_all(), trait_ref)) {
  20         traits::VtableImpl(traits::VtableImplData { impl_def_id, .. }) => {
  21             tcx.coerce_unsized_info(impl_def_id).custom_kind.unwrap()
  22         }
  23         vtable => {
  24             bug!("invalid CoerceUnsized vtable: {:?}", vtable);
  25         }
  26     }
  27 }