Literate haskell accepts spurious \end{code} lines

In #8428 (closed) klao removed a spurious \end{code} from TypeRep.lhs. This made it clear that GHC has accepts spurious \end{code} lines in literate haskell code.

This patch fixes the literate haskell preprocessor to issue an error in this case. Interestingly though, after this change nothing breaks except for klao's already merged patch, so this issue was not found in other .lhs files through GHC.

Trac metadata

Trac field	Value
Version	7.7
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture