Support default class method signatures in Template Haskell

If I say

blah = [d|
  class C a where
    foo :: a -> String
    default foo :: Show a => a -> String
    foo = show
  |]

I get

    Illegal default signature for ‘[foo]’
    Default signatures are not supported by Template Haskell

I would like this feature. I will implement this in due course.

Trac metadata

Trac field	Value
Version	7.8.2
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

changed weight to 5

added Tfeature request TemplateHaskell Trac import labels

See wiki:Design/TemplateHaskellGADTs for a related change to the Dec type I'd like feedback on.

Trac metadata

Trac field	Value
Differential revisions	→ D440

mentioned in commit fe71a7e6

mentioned in commit e4efb7b8

closed

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed
Test case	→ th/T9064

mentioned in commit 786b62aa

added Pnormal label