1 files changed, 73 insertions, 0 deletions
diff --git a/vendor/chalk-solve-0.87.0/src/clauses/builtin_traits/discriminant_kind.rs b/vendor/chalk-solve-0.87.0/src/clauses/builtin_traits/discriminant_kind.rs
new file mode 100644
index 000000000..27d49df75
--- /dev/null
+++ b/vendor/chalk-solve-0.87.0/src/clauses/builtin_traits/discriminant_kind.rs
@@ -0,0 +1,73 @@
+use crate::clauses::ClauseBuilder;
+use crate::{Interner, RustIrDatabase, TraitRef, WellKnownTrait};
+use chalk_ir::{
+    AliasTy, Floundered, Normalize, ProjectionTy, Substitution, Ty, TyKind, TyVariableKind,
+};
+
+pub fn add_discriminant_clauses<I: Interner>(
+    db: &dyn RustIrDatabase<I>,
+    builder: &mut ClauseBuilder<'_, I>,
+    self_ty: Ty<I>,
+) -> Result<(), Floundered> {
+    let interner = db.interner();
+
+    let can_determine_discriminant = match self_ty.data(interner).kind {
+        TyKind::Adt(..)
+        | TyKind::Array(..)
+        | TyKind::Tuple(..)
+        | TyKind::Slice(..)
+        | TyKind::Raw(..)
+        | TyKind::Ref(..)
+        | TyKind::Scalar(_)
+        | TyKind::Str
+        | TyKind::Never
+        | TyKind::FnDef(..)
+        | TyKind::Generator(..)
+        | TyKind::Closure(..)
+        | TyKind::GeneratorWitness(..)
+        | TyKind::Foreign(_)
+        | TyKind::Dyn(_)
+        | TyKind::Function(..)
+        | TyKind::InferenceVar(_, TyVariableKind::Integer)
+        | TyKind::InferenceVar(_, TyVariableKind::Float) => true,
+        TyKind::OpaqueType(..)
+        | TyKind::Alias(_)
+        | TyKind::BoundVar(_)
+        | TyKind::Placeholder(_)
+        | TyKind::AssociatedType(..)
+        | TyKind::Error
+        | TyKind::InferenceVar(..) => false,
+    };
+
+    if !can_determine_discriminant {
+        return Err(Floundered);
+    }
+
+    let disc_ty = db.discriminant_type(self_ty.clone());
+
+    let trait_id = db
+        .well_known_trait_id(WellKnownTrait::DiscriminantKind)
+        .unwrap();
+    let trait_datum = db.trait_datum(trait_id);
+
+    let associated_ty_id = trait_datum.associated_ty_ids[0];
+    let substitution = Substitution::from1(interner, self_ty);
+
+    let trait_ref = TraitRef {
+        trait_id,
+        substitution: substitution.clone(),
+    };
+
+    let normalize = Normalize {
+        alias: AliasTy::Projection(ProjectionTy {
+            associated_ty_id,
+            substitution,
+        }),
+        ty: disc_ty,
+    };
+
+    builder.push_fact(trait_ref);
+    builder.push_fact(normalize);
+
+    Ok(())
+}