cue: fix reentrancy issue
even though this is not something we want to support
Change-Id: I84e986d4b8276d6258679ebc37625565f5fb5c25
diff --git a/doc/ref/spec.md b/doc/ref/spec.md
index 2d30c51..7e0691c 100644
--- a/doc/ref/spec.md
+++ b/doc/ref/spec.md
@@ -2073,6 +2073,23 @@
```
<!--
+Consider banning any construct that makes CUE not having a linear
+running time expressed in the number of nodes in the output.
+
+This would require restricting constructs like:
+
+(fib&{n:2}).out
+
+fib: {
+ n: int
+
+ out: (fib&{n:n-2}).out + (fib&{n:n-1}).out if n >= 2
+ out: fib({n:n-2}).out + fib({n:n-1}).out if n >= 2
+ out: n if n < 2
+}
+
+-->
+<!--
### Unused fields
TODO: rules for detection of unused fields
@@ -2081,7 +2098,6 @@
-->
-
## Modules, instances, and packages
CUE configurations are constructed combining _instances_.
