Fix (xerrors): pushing nil error has no effect #240

	name: Test

	on: [push, pull_request]

	jobs:
	build:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	with:
	fetch-depth: 2
	- uses: actions/setup-go@v5
	with:
	go-version: "1.21"
	- name: test
	run: go test -race -v -coverprofile=coverage.txt -covermode=atomic ./...
	- name: codecov
	uses: codecov/codecov-action@v4.0.1
	with:
	token: ${{ secrets.CODECOV_TOKEN }}

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