GHC accepts `data Foo where` in H2010 mode

According to the Haskell2010 report,

The grammar productions relevant for data declarations are the following:

topdecl	→ data [context =>] simpletype [= constrs] [deriving]

(from 4.2.1 Algebraic Datatype Declarations)

However, GHC 7.0.4/7.4.2/7.6.3/HEAD all happily compile the following Haskell module without any warning when using -XHaskell2010 -Wall, even though this is not valid Haskell2010 afaik:

module Foo where

data Foo where

The trailing where in the data declaration is not valid Haskell2010 (without language extensions such as GADT).

At the very least, this divergence from the Haskell Report should be mentioned in 14.1.1. Divergence from Haskell 98 and Haskell 2010.

Trac metadata

Trac field	Value
Version	7.0.4
Type	Bug
TypeOfFailure	OtherFailure
Priority	low
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture