fix(gnovm): raise error when ranging over nil (#3337)

closes #3336

Co-authored-by: Nathan Toups <[email protected]>

Author: 2 people

gnovm/pkg/gnolang/preprocess.go

@@ -592,6 +592,10 @@ func preprocess1(store Store, ctx BlockNode, n Node) Node {
 				// define key/value.
 				n.X = Preprocess(store, last, n.X).(Expr)
 				xt := evalStaticTypeOf(store, last, n.X)
+				if xt == nil {
+					panic("cannot range over nil")
+				}
+
 				switch xt.Kind() {
 				case MapKind:
 					n.IsMap = true

gnovm/tests/files/range8.gno

@@ -0,0 +1,10 @@
+package main
+
+func main() {
+	for i, v := range nil {
+		println(i, v)
+	}
+}
+
+// Error:
+// main/files/range8.gno:4:2: cannot range over nil