dir=dup
base=none
success=false
-- .git/empty --
empty file to mark repository root
-- dup/go.mod --
module example.com/dup/v2

go 1.13
-- dup/v2/go.mod --
module example.com/dup/v2

go 1.13
-- want --
module is defined in two locations:
	dup/go.mod
	dup/v2/go.mod