diff --git a/cmd/cue/cmd/common.go b/cmd/cue/cmd/common.go
index 6590a04..8429b6d 100644
--- a/cmd/cue/cmd/common.go
+++ b/cmd/cue/cmd/common.go
@@ -36,7 +36,8 @@
 // Disallow
 // - block comments
 // - old-style field comprehensions
-const syntaxVersion = -1000 + 12
+// - space separator syntax
+const syntaxVersion = -1000 + 13
 
 var defaultConfig = &load.Config{
 	Context: build.NewContext(
diff --git a/cmd/cue/cmd/testdata/script/vet.txt b/cmd/cue/cmd/testdata/script/vet.txt
index 68e3664..493934c 100644
--- a/cmd/cue/cmd/testdata/script/vet.txt
+++ b/cmd/cue/cmd/testdata/script/vet.txt
@@ -13,7 +13,7 @@
 	idx: a[str] // should resolve to top-level `a`
 	str: string
 }
-b a b: 4
+b: a: b: 4
 a: {
 	b: 3
 	c: 4