1 files changed, 41 insertions, 0 deletions
diff --git a/vendor/chalk-ir-0.87.0/src/visit/visitors.rs b/vendor/chalk-ir-0.87.0/src/visit/visitors.rs
new file mode 100644
index 000000000..51c087840
--- /dev/null
+++ b/vendor/chalk-ir-0.87.0/src/visit/visitors.rs
@@ -0,0 +1,41 @@
+//! TypeVisitor helpers
+
+use crate::{BoundVar, ControlFlow, DebruijnIndex, Interner, TypeVisitable, TypeVisitor};
+
+/// TypeVisitor extensions.
+pub trait VisitExt<I: Interner>: TypeVisitable<I> {
+    /// Check whether there are free (non-bound) variables.
+    fn has_free_vars(&self, interner: I) -> bool {
+        let flow = self.visit_with(
+            &mut FindFreeVarsVisitor { interner },
+            DebruijnIndex::INNERMOST,
+        );
+        matches!(flow, ControlFlow::Break(_))
+    }
+}
+
+impl<T, I: Interner> VisitExt<I> for T where T: TypeVisitable<I> {}
+
+struct FindFreeVarsVisitor<I: Interner> {
+    interner: I,
+}
+
+impl<I: Interner> TypeVisitor<I> for FindFreeVarsVisitor<I> {
+    type BreakTy = ();
+
+    fn as_dyn(&mut self) -> &mut dyn TypeVisitor<I, BreakTy = Self::BreakTy> {
+        self
+    }
+
+    fn interner(&self) -> I {
+        self.interner
+    }
+
+    fn visit_free_var(
+        &mut self,
+        _bound_var: BoundVar,
+        _outer_binder: DebruijnIndex,
+    ) -> ControlFlow<()> {
+        ControlFlow::Break(())
+    }
+}