leanprover / leanprover/fp-lean
Consider clarification in section 5.1
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Description
In the The Identity Monad section, it says
failed to synthesize instance
HAdd Nat Nat (?m.9063 ?m.9065)
"In this error, the application of one metavariable to another indicates that Lean doesn't run the type-level computation backwards."
I think the intent is to imply that one cannot go from Nat via the inverse of the Id function to obtain Id Nat; and that the metavariables stand for the m type application (I think). However, since that was the first mention of "the type-level computation", perhaps the wording could be clarified a little?
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Research direction
Read section 5.1, especially the “The Identity Monad” passage and its quoted error. Clarify the first use of “type-level computation” and explain what the metavariables indicate, then confirm that the revised wording matches the intended explanation of the Identity Monad example.
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- Domain
- documentation
- Issue type
- Documentation
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 48/100