# Release 1.6.1 (2013-10-28)

This is primarily a bug fix release. Changes of interest are:

- Nix 1.6 accidentally changed the semantics of antiquoted paths in strings, such as `"${/foo}/bar"`. This release reverts to the Nix 1.5.3 behaviour.

- Previously, Nix optimised expressions such as `"${expr}"` to expr. Thus it neither checked whether expr could be coerced to a string, nor applied such coercions. This meant that `"${123}"` evaluatued to `123`, and `"${./foo}"` evaluated to `./foo` (even though `"${./foo} "` evaluates to `"/nix/store/hash-foo "`). Nix now checks the type of antiquoted expressions and applies coercions.

- Nix now shows the exact position of undefined variables. In particular, undefined variable errors in a `with` previously didn't show any position information, so this makes it a lot easier to fix such errors.

- Undefined variables are now treated consistently. Previously, the `tryEval` function would catch undefined variables inside a `with` but not outside. Now `tryEval` never catches undefined variables.

- Bash completion in `nix-shell` now works correctly.

- Stack traces are less verbose: they no longer show calls to builtin functions and only show a single line for each derivation on the call stack.

- New built-in function: `builtins.typeOf`, which returns the type of its argument as a string.