message: Derive an extra Debug
  Summary: Useful to have for debugging stuff.
diff: @@ -135,6 +135,7 @@ fn solve_bindings(
  }
  /// Structure containing all the inferred types.
  +#[derive(Debug)]
  pub struct TypeMap {
  codemap: CodeMap,
  bindings: HashMap<BindingId, (String, Span, Ty)>,
  