compiler/rustc_middle/src/traits/solve.rs

   1 use std::ops::ControlFlow;
   2
   3 use rustc_data_structures::intern::Interned;
   4
   5 use crate::ty::{FallibleTypeFolder, Ty, TypeFoldable, TypeFolder, TypeVisitable, TypeVisitor};
   6
   7 #[derive(Debug, PartialEq, Eq, Copy, Clone, Hash)]
   8 pub struct ExternalConstraints<'tcx>(pub(crate) Interned<'tcx, ExternalConstraintsData<'tcx>>);
   9
  10 impl<'tcx> std::ops::Deref for ExternalConstraints<'tcx> {
  11     type Target = ExternalConstraintsData<'tcx>;
  12
  13     fn deref(&self) -> &Self::Target {
  14         &*self.0
  15     }
  16 }
  17
  18 /// Additional constraints returned on success.
  19 #[derive(Debug, PartialEq, Eq, Clone, Hash, Default)]
  20 pub struct ExternalConstraintsData<'tcx> {
  21     // FIXME: implement this.
  22     pub regions: (),
  23     pub opaque_types: Vec<(Ty<'tcx>, Ty<'tcx>)>,
  24 }
  25
  26 impl<'tcx> TypeFoldable<'tcx> for ExternalConstraints<'tcx> {
  27     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
  28         Ok(FallibleTypeFolder::tcx(folder).intern_external_constraints(ExternalConstraintsData {
  29             regions: (),
  30             opaque_types: self
  31                 .opaque_types
  32                 .iter()
  33                 .map(|opaque| opaque.try_fold_with(folder))
  34                 .collect::<Result<_, F::Error>>()?,
  35         }))
  36     }
  37
  38     fn fold_with<F: TypeFolder<'tcx>>(self, folder: &mut F) -> Self {
  39         TypeFolder::tcx(folder).intern_external_constraints(ExternalConstraintsData {
  40             regions: (),
  41             opaque_types: self.opaque_types.iter().map(|opaque| opaque.fold_with(folder)).collect(),
  42         })
  43     }
  44 }
  45
  46 impl<'tcx> TypeVisitable<'tcx> for ExternalConstraints<'tcx> {
  47     fn visit_with<V: TypeVisitor<'tcx>>(
  48         &self,
  49         visitor: &mut V,
  50     ) -> std::ops::ControlFlow<V::BreakTy> {
  51         self.regions.visit_with(visitor)?;
  52         self.opaque_types.visit_with(visitor)?;
  53         ControlFlow::Continue(())
  54     }
  55 }