SerializedCompact has a [(Ptr a, Word)] instead of a custom datatype

data SerializedCompact a = SerializedCompact
  { serializedCompactBlockList :: [(Ptr a, Word)]
  , serializedCompactRoot :: Ptr a
  }

I'm not sure why the first member of SerializedCompact isn't something like

data CompactBlock a = CompactBlock {-# UNPACK #-} (Ptr a) {-# UNPACK #-} Word

so the Ptr can unpack into the constructor, which isn't possible with (,). SerializedCompact would then look like

data SerializedCompact a = SerializedCompact
  { serializedCompactBlockList :: [CompactBlock a]
  , serializedCompactRoot :: Ptr a
  }

Trac metadata

Trac field	Value
Version	8.4.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	libraries/compact
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	andrewthad, ezyang
Operating system
Architecture