fix: handle empty interface conversion

_test/interface42.go

@@ -0,0 +1,12 @@
+package main
+
+import "fmt"
+
+func main() {
+	v := interface{}(0)
+
+	fmt.Println(v)
+}
+
+// Output:
+// 0

interp/cfg.go

@@ -383,7 +383,7 @@ func (interp *Interpreter) cfg(root *node, pkgID string) ([]*node, error) {
 				}
 			}
 
-		case arrayType, basicLit, chanType, funcType, mapType, structType:
+		case arrayType, basicLit, chanType, funcType, interfaceType, mapType, structType:
 			n.typ, err = nodeType(interp, sc, n)
 			return false
 		}