upgrading to v4, change of "req.backend.healthy" -> "std.healthy(req.backend)" reports "Symbol not found: 'std.healthy' (expected type BOOL)"

[grantksupport at operamail.com]

Digging around, guess this IS a separate issue.

According to

	"req.backend.healthy replaced by std.healthy(req.backend)"

I changed in my vcl

		...
	-           if (req.backend.healthy) {
223     +           if (std.healthy(req.backend)) {
		        set req.grace = 30s;
		    } else {
		        set req.grace = 1h;
		    }  
		...


but config check reports

	Message from VCC-compiler:
	Symbol not found: 'std.healthy' (expected type BOOL):
	('input' Line 223 Pos 13)
	        if (std.healthy(req.backend)) {
	------------###########----------------

	Running VCC-compiler failed, exit 1

	VCL compilation failed

I found the original commit @

 "[master] 351e100 Add BOOL std.healthy(BACKEND) which can check if any
 backend is healthy, rather than have hardcoded variables for
 req.backend and bereq.backend's health"
  https://www.varnish-cache.org/lists/pipermail/varnish-commit/2013-November/010284.html

and a question about usage @

 "Questiona about req.backend.healthy"
  https://www.varnish-cache.org/lists/pipermail/varnish-misc/2013-June/023139.html

but don't understand the problem.

Grant