bug fixes and performance improvements

src/interner/mod.rs

@@ -0,0 +1,9 @@
+mod monotype;
+mod multitype;
+mod token;
+mod display;
+
+pub use monotype::TypedInterner;
+pub use multitype::Interner;
+pub use token::Token;
+pub use display::{DisplayBundle, InternedDisplay};