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	 	Two minor wibbles
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[These two unrelated fixes just got tangled together in my tree.]

1.  Fix a crash when a class op is used as a record selector

2.  Fix a wibble related to the new DataCon naming story.
    In tcId, treat the DataCon case entirely separately, because
    its "stupid context" doesn't show up in its type.

    On the way, remove the DataCon cases in tcLookupId and tcLookupGlobalId
    The should not be necessary.  He says hopefully.