The Coq mailing list

[Vadim Zaliva <vzaliva AT cmu.edu>]

On Wed, Aug 17, 2016 at 12:29 AM, Matthieu Sozeau <mattam AT mattam.org> wrote:

I'm not sure why you would need to specify a relation for setoid_rewrite, as it is always inferred from the lemma itself. Do you have an example?

I just have a situation where:

replace a with b by apply compose_assoc.

works instantly

while

setoid_rewrite <- compose_assoc at 9.

takes forever. I haven not been able to see if it finishes. Here is a log

file for first few minutes:

https://www.dropbox.com/s/51rrlkgo3okupq7/log2.out.bz2?dl=0

expressions 'a' and 'b' are approximately 400 lines long each. Even if I use (set with wildcards trick proposed by Laurent, I do not have to spell out 'a' but I still need manually construct and write down 'b'. So making 'setoid_rewrite ... at n' could really help here.

My initial theory was that it was using wrong relation for rewriting and tries and fails to find all Proper instances required for such rewrite. But apparently it is something else.

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