1 files changed, 78 insertions, 0 deletions
diff --git a/compiler/rustc_trait_selection/src/solve/infcx_ext.rs b/compiler/rustc_trait_selection/src/solve/infcx_ext.rs
new file mode 100644
index 000000000..42f597c78
--- /dev/null
+++ b/compiler/rustc_trait_selection/src/solve/infcx_ext.rs
@@ -0,0 +1,78 @@
+use rustc_infer::infer::at::ToTrace;
+use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
+use rustc_infer::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime};
+use rustc_infer::traits::query::NoSolution;
+use rustc_infer::traits::ObligationCause;
+use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
+use rustc_middle::ty::{self, Ty, TypeFoldable};
+use rustc_span::DUMMY_SP;
+
+use super::Goal;
+
+/// Methods used inside of the canonical queries of the solver.
+///
+/// Most notably these do not care about diagnostics information.
+/// If you find this while looking for methods to use outside of the
+/// solver, you may look at the implementation of these method for
+/// help.
+pub(super) trait InferCtxtExt<'tcx> {
+    fn next_ty_infer(&self) -> Ty<'tcx>;
+    fn next_const_infer(&self, ty: Ty<'tcx>) -> ty::Const<'tcx>;
+
+    fn eq<T: ToTrace<'tcx>>(
+        &self,
+        param_env: ty::ParamEnv<'tcx>,
+        lhs: T,
+        rhs: T,
+    ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution>;
+
+    fn instantiate_bound_vars_with_infer<T: TypeFoldable<'tcx> + Copy>(
+        &self,
+        value: ty::Binder<'tcx, T>,
+    ) -> T;
+}
+
+impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
+    fn next_ty_infer(&self) -> Ty<'tcx> {
+        self.next_ty_var(TypeVariableOrigin {
+            kind: TypeVariableOriginKind::MiscVariable,
+            span: DUMMY_SP,
+        })
+    }
+    fn next_const_infer(&self, ty: Ty<'tcx>) -> ty::Const<'tcx> {
+        self.next_const_var(
+            ty,
+            ConstVariableOrigin { kind: ConstVariableOriginKind::MiscVariable, span: DUMMY_SP },
+        )
+    }
+
+    #[instrument(level = "debug", skip(self, param_env), ret)]
+    fn eq<T: ToTrace<'tcx>>(
+        &self,
+        param_env: ty::ParamEnv<'tcx>,
+        lhs: T,
+        rhs: T,
+    ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution> {
+        self.at(&ObligationCause::dummy(), param_env)
+            .define_opaque_types(false)
+            .eq(lhs, rhs)
+            .map(|InferOk { value: (), obligations }| {
+                obligations.into_iter().map(|o| o.into()).collect()
+            })
+            .map_err(|e| {
+                debug!(?e, "failed to equate");
+                NoSolution
+            })
+    }
+
+    fn instantiate_bound_vars_with_infer<T: TypeFoldable<'tcx> + Copy>(
+        &self,
+        value: ty::Binder<'tcx, T>,
+    ) -> T {
+        self.replace_bound_vars_with_fresh_vars(
+            DUMMY_SP,
+            LateBoundRegionConversionTime::HigherRankedType,
+            value,
+        )
+    }
+}