/cc @dr2chase @dvyukov

In case the link above breaks, the code in question is:

func makeCutsetFunc(cutset string) func(rune) bool {
    return func(r rune) bool { return IndexRune(cutset, r) >= 0 }
}

// Trim returns a slice of the string s with all leading and
// trailing Unicode code points contained in cutset removed.
func Trim(s string, cutset string) string {
    if s == "" || cutset == "" {
        return s
    }
    return TrimFunc(s, makeCutsetFunc(cutset))
}

I have a WIP for this, which seems to work fine when building a single-package executable but fails as soon as multiple packages are involved since the exporter/importer do not handle OCLOSURE.

@griesemer I'm trying to add support for the OCLOSURE node in the export format but I'm not able to test my changes because I keep getting the following error when I try compile code with: cannot import "runtime/internal/sys" due to version skew - reinstall package (unknown export format version 6 ("version 6"))

How does one test changes to the export format? Is the workflow affected by the recent caching work by @rsc ?

edit: nevermind, I stupidly forgot to update the version check in bimport.go...

@davecheney I figured out what was going wrong. Thanks for the offer to help though :)

At this point, my WIP can inline functions with closures that do not capture variables and works fine across packages. I'll upload a CL as soon as I figure out how to properly handle captures (or when I get stuck and need to ask for help).

Interestingly, Trim is no longer a good benchmark for this since the introduction of an ASCII fast path brought a loop into makeCutsetFunc which prevents inlining (this is #14768).

Change https://golang.org/cl/97415 mentions this issue: cmd/compile: export/import OCLOSURE