src/librustc_traits/generic_types.rs

   1 //! Utilities for creating generic types with bound vars in place of parameter values.
   2
   3 use rustc::ty::{self, Ty, TyCtxt};
   4 use rustc::ty::subst::{GenericArg, SubstsRef, InternalSubsts};
   5 use rustc::hir;
   6 use rustc::hir::def_id::DefId;
   7 use rustc_target::spec::abi;
   8
   9 crate fn bound(tcx: TyCtxt<'tcx>, index: u32) -> Ty<'tcx> {
  10     let ty = ty::Bound(
  11         ty::INNERMOST,
  12         ty::BoundVar::from_u32(index).into()
  13     );
  14     tcx.mk_ty(ty)
  15 }
  16
  17 crate fn raw_ptr(tcx: TyCtxt<'tcx>, mutbl: hir::Mutability) -> Ty<'tcx> {
  18     tcx.mk_ptr(ty::TypeAndMut {
  19         ty: bound(tcx, 0),
  20         mutbl,
  21     })
  22 }
  23
  24 crate fn fn_ptr(
  25     tcx: TyCtxt<'tcx>,
  26     arity_and_output: usize,
  27     c_variadic: bool,
  28     unsafety: hir::Unsafety,
  29     abi: abi::Abi,
  30 ) -> Ty<'tcx> {
  31     let inputs_and_output = tcx.mk_type_list(
  32         (0..arity_and_output).into_iter()
  33             .map(|i| ty::BoundVar::from(i))
  34             // DebruijnIndex(1) because we are going to inject these in a `PolyFnSig`
  35             .map(|var| tcx.mk_ty(ty::Bound(ty::DebruijnIndex::from(1usize), var.into())))
  36     );
  37
  38     let fn_sig = ty::Binder::bind(ty::FnSig {
  39         inputs_and_output,
  40         c_variadic,
  41         unsafety,
  42         abi,
  43     });
  44     tcx.mk_fn_ptr(fn_sig)
  45 }
  46
  47 crate fn type_list(tcx: TyCtxt<'tcx>, arity: usize) -> SubstsRef<'tcx> {
  48     tcx.mk_substs(
  49         (0..arity).into_iter()
  50             .map(|i| ty::BoundVar::from(i))
  51             .map(|var| tcx.mk_ty(ty::Bound(ty::INNERMOST, var.into())))
  52             .map(|ty| GenericArg::from(ty))
  53     )
  54 }
  55
  56 crate fn ref_ty(tcx: TyCtxt<'tcx>, mutbl: hir::Mutability) -> Ty<'tcx> {
  57     let region = tcx.mk_region(
  58         ty::ReLateBound(ty::INNERMOST, ty::BoundRegion::BrAnon(0))
  59     );
  60
  61     tcx.mk_ref(region, ty::TypeAndMut {
  62         ty: bound(tcx, 1),
  63         mutbl,
  64     })
  65 }
  66
  67 crate fn fn_def(tcx: TyCtxt<'tcx>, def_id: DefId) -> Ty<'tcx> {
  68     tcx.mk_ty(ty::FnDef(def_id, InternalSubsts::bound_vars_for_item(tcx, def_id)))
  69 }
  70
  71 crate fn closure(tcx: TyCtxt<'tcx>, def_id: DefId) -> Ty<'tcx> {
  72     tcx.mk_closure(def_id, InternalSubsts::bound_vars_for_item(tcx, def_id))
  73 }
  74
  75 crate fn generator(tcx: TyCtxt<'tcx>, def_id: DefId) -> Ty<'tcx> {
  76     tcx.mk_generator(
  77         def_id,
  78         InternalSubsts::bound_vars_for_item(tcx, def_id),
  79         hir::Movability::Movable
  80     )
  81 }