Variadic expression parameters

[fyfyrchik]

I want to do something like this:

@@
var s, low, up expression
@@
+import "slices"
-s = append(s[:low], s[up:]...)
+s = slices.Delete(s, low, up)

It doesn't work:

load patch "delete.patch": parse: delete.patch/0.minus.augmented:4:27: missing ',' in argument list

Supposably because ... is considered as a hole.
Using identifier instead of s[up:] works correctly, which matches the code

gopatch/internal/pgo/augment/find.go

Lines 178 to 185 in 2ae6b02

	func (f *finder) ident() {
	f.next() // IDENT
	// foo...
	if f.tok == token.ELLIPSIS {
	f.next() // leave unchanged
	}
	}

I haven't found a quick way to fix this, because it is not obvious what context we need to track and remember.