Annotation extension needs a flag

[simonmar]

There's no flag to enable the annotations extension, as far as I can tell.

[igloo]

Annotations are pragmas, which we haven't historically had extensions for. Some options:

• Do nothing.
• Ignore (but warn about) ANN pragmas if TemplateHaskell is off (I infer from the docs that they rely on TH). If they are a well-behaved pragma then ignoring them won't affect the correctness of the code.
• Add an extension for annotations.
• Add an extension for each pragma GHC knows about.

[igloo]

Consensus was "do nothing".

[nomeata]

Can you please reconsider option two? On Debian, we have several arches where ghci does not work. It is already a pitty that we cannot build any TH-using library there, but now we also have to remove anything using annotation, e.g. haskell-vector.

Thanks, Joachim