testing: panic swallowed if t.Cleanup calls t.Fatal

What version of Go are you using (go version)?

$ go version
go version go1.17.7 darwin/amd64

Does this issue reproduce with the latest release?

Yes, including go1.18rc1.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="${HOME}/Library/Caches/go-build"
GOENV="${HOME}/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="${HOME}/.gvm/pkgsets/go1.17.7/global/pkg/mod"
GOOS="darwin"
GOPATH="${HOME}/.gvm/pkgsets/go1.17.7/global"
GOPROXY="https://proxy.golang.org,direct"
GOROOT="${HOME}/.gvm/gos/go1.17.7"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="${HOME}/.gvm/gos/go1.17.7/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="go1.17.7"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/rn/xy02hv_5403f5ln4wbs47hsc0000gp/T/go-build1816554494=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Called t.Fatal from a t.Cleanup function for a test that panicked, see: https://go.dev/play/p/Q3zMx79r8gA

func TestPanicSwallowedByCleanup(t *testing.T) {
	t.Cleanup(func() {
		// This causes the panic to never be logged:
		t.Fatal("problem during cleanup")
	})
	panic("kaboom")
}

What did you expect to see?

The panic encountered in the test to be reported with a full stack trace, as would be the case if t.Error was called from the t.Cleanup, see: https://go.dev/play/p/iV4-JV4ArBf

=== RUN   TestPanicWithCleanup
    prog.go:10: problem during cleanup
--- FAIL: TestPanicWithCleanup (0.00s)
panic: kaboom [recovered]
	panic: kaboom

goroutine 6 [running]:
testing.tRunner.func1.2({0x4b6440, 0x4ee1a8})
	/usr/local/go-faketime/src/testing/testing.go:1209 +0x24e
testing.tRunner.func1()
	/usr/local/go-faketime/src/testing/testing.go:1212 +0x218
panic({0x4b6440, 0x4ee1a8})
	/usr/local/go-faketime/src/runtime/panic.go:1038 +0x215
main.TestPanicWithCleanup(0xc000001ba0)
	/tmp/sandbox3107448856/prog.go:12 +0x65
testing.tRunner(0xc000001ba0, 0x4d4d80)
	/usr/local/go-faketime/src/testing/testing.go:1259 +0x102
created by testing.(*T).Run
	/usr/local/go-faketime/src/testing/testing.go:1306 +0x35a

Program exited.

What did you see instead?

The original panic is completely omitted, we only see the t.Fatal output:

=== RUN   TestPanicSwallowedByCleanup
    prog.go:10: problem during cleanup
--- FAIL: TestPanicSwallowedByCleanup (0.00s)
FAIL

Program exited.

Note, this is possibly related to: #49929

[seankhliao]

Duplicate of #29207