Problem exists with all versions of go.

go tool vet supports args as either:

1. files, all of which must be in the same package.
2. a single directory, recursively descends the directory, vetting each package it finds.

Using files causes errors when there are external packages in the directory (ex: example_test.go uses pkg_test). The error is something like ExampleNewFilter refers to unknown identifier: NewFilter.

Using a directory walks the entire tree, which makes it impossible to ignore specific paths.

I propose to fix this issue by adding a --no-recurse flag to prevent the directory walk.