sig, _ := sel.Type().(*Signature)
		if sel.Kind() == MethodVal {
			got := sig.Recv().Type()
			want := sel.Recv()
			if !Identical(got, want) {
				t.Errorf("%s: Recv() = %s, want %s", segment, got, want)
			}
		} else if sig != nil && sig.Recv() != nil {
			t.Errorf("%s: signature has receiver %s", sig, sig.Recv().Type())
		}
	}
	// Assert that all wantOut entries were used exactly once.

		if (re.res == nil) == (re.err == nil) {
			panic(fmt.Sprintf("internal error: exactly one of res or err should be set; nil=%v", re.res == nil))
		}
		if debugRoundTrip {
			req.logf("resc recv: %p, %T/%#v", re.res, re.err, re.err)
		}
		if re.err != nil {
			return nil, pc.mapRoundTripError(req, startBytesWritten, re.err)
		}
		return re.res, nil
	}

	var respHeaderTimer <-chan time.Time

	case SendDir:
		s = "chan<- " + stringFor(typ)
	case RecvDir:
		s = "<-chan " + stringFor(typ)
	case BothDir:
		typeStr := stringFor(typ)
		if typeStr[0] == '<' {
			// typ is recv chan, need parentheses as "<-" associates with leftmost
			// chan possible, see:
			// * https://golang.org/ref/spec#Channel_types
			// * https://github.com/golang/go/issues/39897
			s = "chan (" + typeStr + ")"