I only took a brief look at this, but this seems to be a tricky one. You could try: go get github.com/ugorji/go/codec@none
That made your example then work for me locally. >From the doc (https://golang.org/cmd/go/#hdr-Module_aware_go_get): "The version suffix @none indicates that the dependency should be removed entirely, downgrading or removing modules depending on it as needed." However, then using the resulting go.mod on the playground fails with a different error: https://play.golang.org/p/EB5T7yuRQSC I did not look into that error, but I am not sure if that is a playground specific problem with the playground's new module support, or maybe some package has some NaCl build tag issue, or something else entirely. (It is fun, though, to add a go.mod to the playground!) It seems viper might be depending on an older problematic version of github.com/ugorji/go/codec. I would recommend you add your example to this viper issue here: https://github.com/spf13/viper/issues/658 The viper project might need to update their go.mod and issue a new viper release, but not 100% sure. Some additional related discussion in: https://github.com/gin-gonic/gin/issues/1897 https://github.com/golang/go/issues/29332#issuecomment-448669442 It probably also makes sense to open a clean new issue on the Go issue tracker with your example, and ask for a clearer diagnostic message or a simpler solution. (The Go issue mentioned above is closed). Sorry that is not a great answer, thepudds On Friday, May 17, 2019 at 4:52:12 PM UTC-4, Jérôme LAFORGE wrote: > > How can I import this both modules without ambiguous? > > https://play.golang.org/p/YgrEmcTallk > > Thx for your help. > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/e41cc46b-711d-4ac9-b16e-ae94b5f24290%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.