map<clause_t, valid_t> looks wrong in schedule.cxx

[eschnett]

For example, line 1774 in schedule.cxx reads:

    map<clause_t, valid_t> isread;

This maps a clause_t (which contains a valid_t field) to a valid_t. This looks wrong. @stevenrbrandt suggests to have the clause_t comparison operator ignore the valid_t field. @eschnett thinks that maybe this valid_t field should be there in the first case, at least not for this map.

[stevenrbrandt]

I'm slightly confused. What is "the first case?"

[eschnett]

That's just an English expression, read as "[...] field should not be there".

[stevenrbrandt]

Ah, the English expression is actually "in the first place." So we should change the == and < operators?

[eschnett]

Not yet, the code looks wrong, I want to investigate first.