compiler/rustc_trait_selection/src/solve/infcx_ext.rs

   1 use rustc_infer::infer::canonical::CanonicalVarValues;
   2 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
   3 use rustc_infer::infer::InferCtxt;
   4 use rustc_infer::traits::query::NoSolution;
   5 use rustc_middle::ty::Ty;
   6 use rustc_span::DUMMY_SP;
   7
   8 use crate::solve::ExternalConstraints;
   9
  10 use super::{Certainty, QueryResult, Response};
  11
  12 /// Methods used inside of the canonical queries of the solver.
  13 pub(super) trait InferCtxtExt<'tcx> {
  14     fn next_ty_infer(&self) -> Ty<'tcx>;
  15
  16     fn make_canonical_response(
  17         &self,
  18         var_values: CanonicalVarValues<'tcx>,
  19         certainty: Certainty,
  20     ) -> QueryResult<'tcx>;
  21 }
  22
  23 impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
  24     fn next_ty_infer(&self) -> Ty<'tcx> {
  25         self.next_ty_var(TypeVariableOrigin {
  26             kind: TypeVariableOriginKind::MiscVariable,
  27             span: DUMMY_SP,
  28         })
  29     }
  30
  31     fn make_canonical_response(
  32         &self,
  33         var_values: CanonicalVarValues<'tcx>,
  34         certainty: Certainty,
  35     ) -> QueryResult<'tcx> {
  36         let external_constraints = take_external_constraints(self)?;
  37
  38         Ok(self.canonicalize_response(Response { var_values, external_constraints, certainty }))
  39     }
  40 }
  41
  42 #[instrument(level = "debug", skip(infcx), ret)]
  43 fn take_external_constraints<'tcx>(
  44     infcx: &InferCtxt<'tcx>,
  45 ) -> Result<ExternalConstraints<'tcx>, NoSolution> {
  46     let region_obligations = infcx.take_registered_region_obligations();
  47     let opaque_types = infcx.take_opaque_types_for_query_response();
  48     Ok(ExternalConstraints {
  49         // FIXME: Now that's definitely wrong :)
  50         //
  51         // Should also do the leak check here I think
  52         regions: drop(region_obligations),
  53         opaque_types,
  54     })
  55 }