Guile already allows mixed definitions and expressions in let bodies (since 2.9.4), which isn't in any of the Scheme reports. It's up to authors to avoid or isolate Guile extensions if they want to remain rnrs compatible, and this patch doesn't change that.
Being able to put definitions in the body of let but not in the bodies of these other forms is an artificial restriction. Some forms still aren't fixed, like match. I believe we should eventually fix those as well. I think the root of the issue is (begin), but the patch goes in the right direction. Regards Daniel
