func (e *Expectation) Check(err error) error {
	if !e.failure && err != nil {
		return fmt.Errorf("unexpected error while reading the trace: %v", err)
	}
	if e.failure && err == nil {
		return fmt.Errorf("expected error while reading the trace: want something matching %q, got none", e.errorMatcher)
	}
	if e.failure && err != nil && !e.errorMatcher.MatchString(err.Error()) {

	alertDecryptionFailed:             "decryption failed",
	alertRecordOverflow:               "record overflow",
	alertDecompressionFailure:         "decompression failure",
	alertHandshakeFailure:             "handshake failure",
	alertBadCertificate:               "bad certificate",
	alertUnsupportedCertificate:       "unsupported certificate",
	alertCertificateRevoked:           "revoked certificate",

-- expect --
FAILURE ".*expected a proc but didn't have one.*"
-- trace --
Trace Go1.22
EventBatch gen=1 m=0 time=0 size=34
GoCreateSyscall dt=1 new_g=4
ProcStatus dt=1 p=0 pstatus=2
ProcStart dt=1 p=0 p_seq=1
GoSyscallEndBlocked dt=1
GoStart dt=1 g=4 g_seq=1
GoSyscallBegin dt=1 p_seq=2 stack=0
GoDestroySyscall dt=1
GoCreateSyscall dt=1 new_g=4
GoSyscallEnd dt=1
GoSyscallBegin dt=1 p_seq=3 stack=0
GoDestroySyscall dt=1

-- expect --
FAILURE "expected a proc but didn't have one"
-- trace --
Trace Go1.22
EventBatch gen=1 m=0 time=0 size=5
Frequency freq=15625000
EventBatch gen=1 m=0 time=0 size=5
GoCreate dt=0 new_g=1 new_stack=0 stack=0

	KDSA R0, R4      // compute digital signature authentication
	BVS  loop        // branch back if interrupted
	BGT  retry       // signing unsuccessful, but retry with new CSPRN
	BLT  error       // condition code of 1 indicates a failure

success:
	MOVD $0, errn+16(FP) // return 0 - sign/verify was successful
	RET

error:
	MOVD $1, errn+16(FP) // return 1 - sign/verify failed
	RET

retry:

	size    int64
	cur     int64
	mu      sync.Mutex
	waiters list.List
}

// Acquire acquires the semaphore with a weight of n, blocking until resources
// are available or ctx is done. On success, returns nil. On failure, returns
// ctx.Err() and leaves the semaphore unchanged.
func (s *Weighted) Acquire(ctx context.Context, n int64) error {
	done := ctx.Done()

	s.mu.Lock()
	select {
	case <-done:

	-- $WORK/d2/src/p2/p2.go --
	package p2
	func F() {}
	-- $WORK/p2x.go --
	package p2
	func F() {}
	func G() {}

The bug is that the final phase installs p11 instead of p1. The test failure looks like:

	$ go test -run=Script
	--- FAIL: TestScript (3.75s)
	    --- FAIL: TestScript/install_rebuild_gopath (0.16s)
	        script_test.go:223:
	            # GOPATH with p1 in d2, p2 in d2 (0.000s)

	Requires: []*analysis.Analyzer{inspect.Analyzer},
	Run:      run,
}

// assertableTo checks whether interface v can be asserted into t. It returns
// nil on success, or the first conflicting method on failure.
func assertableTo(free *typeparams.Free, v, t types.Type) *types.Func {
	if t == nil || v == nil {
		// not assertable to, but there is no missing method
		return nil
	}
	// ensure that v and t are interfaces

	// if there's already an idle cached connection available.
	GetConn func(hostPort string)

	// GotConn is called after a successful connection is
	// obtained. There is no hook for failure to obtain a
	// connection; instead, use the error from
	// Transport.RoundTrip.
	GotConn func(GotConnInfo)

	// PutIdleConn is called when the connection is returned to

	out, err := cmd.CombinedOutput()
	if exit == 1 {
		if err == nil {
			log.Fatal("stressExec: unexpected exec success")
		}
		return
	}
	if err != nil {
		log.Fatalf("stressExec: exec failure: %v: %s", err, out)
	}
	wantOutput += "\n"
	if string(out) != wantOutput {
		log.Fatalf("stressExec: exec output = %q; want %q", out, wantOutput)
	}
	Println("did exec")
}

func stressExec() {