erris is a program for checking that errors are compared or type asserted using go1.13 errors.Is and errors.As functions.

go get -u github.com/romanyx/erris/cmd/erris

For basic usage, just give the package path of interest as the first argument:

erris github.com/romanyx/erris/testdata

Outputs:

github.com/romanyx/erris/testdata/main.go:14:5:	use errors.Is to compare an error
github.com/romanyx/erris/testdata/main_test.go:11:14:	use errors.As to type assert an error

To check all packages beneath the current directory:

erris ./...