One of our other tests, go/test/typeparam/chans.go fails without those lines. But we really don't want those lines (and they cause problems in other cases such as yours), so we will work on figuring out the chans.go issue and a better way to fix it. The CalcSize/CheckSize is always an issue - should really just be done by one pass through all the relevant types closer to the back end.
changed the title
cmd/compile: compiler ice on checking size for type looped chan.Aug 23, 2021