Data family constructors defined in GHCi are not in scope

[parcs]

The following example explains the problem:

> data family Foo a
> data instance Foo Int = FooInt
> :t FooInt

<interactive>:1:1: Not in scope: data constructor `FooInt'

FooInt is defined, but GHCi doesn't recognize it.

[parcs]

Potential fix

[simonmar]

Patch looks ok, we'll need a test too.

[p.capriotti@…]

commit 700d287fb11dadfd1e91875e2008c4002cd883a3

Author: Paolo Capriotti <p.capriotti@gmail.com>
Date:   Mon Aug 13 18:26:34 2012 +0100

    Fix environment update for type instance declarations in GHCi (#7117)
    
    Patch by Patrick Palka <patrick@parcs.ath.cx>

 compiler/typecheck/TcInstDcls.lhs |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

[simonpj]

Paolo to make a test case, and merge to 7.6.

[pcapriotti]

Test was pushed as 38163b919c9b429a003468afe2ac93f9bc9bd3f0. Merged as 8c668678afe42bdc29f01eb49c791c13be3f94dc.