1.6. Release notes for version 6.12.2
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## 1.6. Release notes for version 6.12.2

The significant changes to the various parts of the compiler are listed in the following sections. There have also been numerous bug fixes and performance improvements over the 6.10 branch.

### 1.6.1. Compiler and Runtime system

- A new flag `-no-rtsopts` flag allows you to disable parsing of `+RTS ...` options by the run-time system.

  In some use-cases, when a program can be run as another user, this can cause security problems. For example, `myprog -tsomefile` will overwrite `somefile` if the other user has permissions to do so.

- The mingw installation bundled with GHC on Windows now includes a C++ compiler again.

- Support for the FreeBSD, Dragonfly and Haiku OSes has been improved.

- Datatypes with a context but no constructors, e.g.

      data Show a => T a

  are accepted again.

- Importing qualified names is now an error.

- `ghc-pkg` now ensures that the conf files it writes are UTF8.

- The parsing of tracing flags has changed; see Section 4.15.6, “Tracing” for details.

### 1.6.2. Template Haskell

- A bug in the kind parser has been fixed.

### 1.6.3. Libraries

#### 1.6.3.1. array

- No change; version 0.3.0.0.

#### 1.6.3.2. base

- Version number 4.2.0.1 (was 4.2.0.0)

#### 1.6.3.3. bytestring

- Version number 0.9.1.6 (was 0.9.1.5).

#### 1.6.3.4. Cabal

- Version number 1.8.0.4 (was 1.8.0.2)

- `Distribution.ModuleName.simple` has been deprecated; use `Distribution.ModuleName.fromString` instead.

#### 1.6.3.5. containers

- No change; version 0.3.0.0.

#### 1.6.3.6. directory

- Version number 1.0.1.1 (was 1.0.1.0)

- `System.Directory.doesFileExist` on Unix-like OSes now correctly identifies various types of special file as files.

#### 1.6.3.7. dph (dph-base, dph-par, dph-prim-interface, dph-prim-par, dph-prim-seq, dph-seq)

- All the dph packages are version 0.4.0.

#### 1.6.3.8. extensible-exceptions

- No change; version 0.1.1.1.

#### 1.6.3.9. filepath

- Version number 1.1.0.4 (was 1.1.0.3)

#### 1.6.3.10. ghc-binary

- This is an internal package, and should not be used.

#### 1.6.3.11. ghc-prim

- No change; version 0.2.0.0.

#### 1.6.3.12. haskell98

- No change; version 1.0.1.1.

#### 1.6.3.13. hpc

- Version number 0.5.0.5 (was 0.5.0.4)

#### 1.6.3.14. integer-gmp

- Version number 0.2.0.1 (was 0.2.0.0)

#### 1.6.3.15. integer-simple

- No change; version 0.1.0.0.

#### 1.6.3.16. old-locale

- No change; version 1.0.0.2.

#### 1.6.3.17. old-time

- Version number 1.0.0.4 (was 1.0.0.3)

#### 1.6.3.18. pretty

- No change; version 1.0.1.1.

#### 1.6.3.19. process

- No change; version 1.0.1.2.

#### 1.6.3.20. random

- No change; version 1.0.0.2.

#### 1.6.3.21. syb

- No change; version 0.1.0.2.

#### 1.6.3.22. template-haskell

- Version number 2.4.0.1 (was 2.4.0.0)

#### 1.6.3.23. time

- No change; version 1.1.4.

#### 1.6.3.24. unix

- Version number 2.4.0.1 (was 2.4.0.0)

#### 1.6.3.25. Win32

- Version number 2.2.0.2 (was 2.2.0.1)

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