1 files changed, 34 insertions, 0 deletions
diff --git a/vendor/chalk-engine/src/derived.rs b/vendor/chalk-engine/src/derived.rs
new file mode 100644
index 000000000..b3cdc3d0d
--- /dev/null
+++ b/vendor/chalk-engine/src/derived.rs
@@ -0,0 +1,34 @@
+// These impls for PartialEq, Eq, etc are written by hand. This is
+// because the `#[derive()]` would add requirements onto the context
+// object that are not needed.
+
+use super::*;
+use std::cmp::{Eq, PartialEq};
+use std::hash::{Hash, Hasher};
+use std::mem;
+
+///////////////////////////////////////////////////////////////////////////
+
+impl<I: Interner> PartialEq for Literal<I> {
+    fn eq(&self, other: &Literal<I>) -> bool {
+        match (self, other) {
+            (Literal::Positive(goal1), Literal::Positive(goal2))
+            | (Literal::Negative(goal1), Literal::Negative(goal2)) => goal1 == goal2,
+
+            _ => false,
+        }
+    }
+}
+
+impl<I: Interner> Eq for Literal<I> {}
+
+impl<I: Interner> Hash for Literal<I> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        mem::discriminant(self).hash(state);
+        match self {
+            Literal::Positive(goal) | Literal::Negative(goal) => {
+                goal.hash(state);
+            }
+        }
+    }
+}