diff --git a/examples/test.rs b/examples/test.rs
index 9a72790..84f33e4 100644
--- a/examples/test.rs
+++ b/examples/test.rs
@@ -1,10 +1,11 @@
-use clingo::ast::{guard, symbolic_term, ComparisonOperator, Location};
+use clingo::ast::{symbolic_term, ComparisonOperator, Guard, Location, SymbolicTerm, Term, AST};
 use clingo::Symbol;
 use clingo_sys::*;
+use core::marker::PhantomData;
+use core::ptr::NonNull;
+use std::ffi::{CStr, CString};
 
 fn raw() {
-    use std::ffi::{CStr, CString};
-
     let file = CString::new("").unwrap();
     let location = clingo_location {
         begin_line: 0,
@@ -68,12 +69,38 @@ fn raw() {
     assert_eq!(res, " > \"test\"".to_string());
 }
 
-fn wrapped() {
-    use clingo::ast::{Guard, Term, AST};
-    use core::marker::PhantomData;
-    use core::ptr::NonNull;
-    use std::ffi::{CStr, CString};
+fn xguard<'a, T>(gt: ComparisonOperator, symbolic_term: T) -> Result<Guard<'a>, ()>
+where
+    T: Into<Term<'a>>,
+{
+    let term: Term = symbolic_term.into();
+    let mut guard = std::ptr::null_mut();
+    if !unsafe {
+        clingo_ast_build(
+            clingo_ast_type_e_clingo_ast_type_guard as i32,
+            &mut guard,
+            gt,
+            term.ast,
+        )
+    } {
+        panic!("clingo_ast_build() guard failed.");
+    }
+    let _ = gt;
+    let _ = term;
+    let _ = symbolic_term;
+
+    match NonNull::new(guard) {
+        Some(ast) => Ok(Guard {
+            ast: AST {
+                ptr: ast,
+                _lifetime: PhantomData,
+            },
+        }),
+        None => Err(()),
+    }
+}
 
+fn wrapped() {
     let loc = Location::default();
     let mut symbol = 0;
     let c_str = CString::new("test").unwrap();
@@ -108,30 +135,34 @@ fn wrapped() {
 
     let gt = ComparisonOperator::GreaterThan;
 
-    let term : Term = symbolic_term.into();
-    let mut guard = std::ptr::null_mut();
-    if !unsafe {
-        clingo_ast_build(
-            clingo_ast_type_e_clingo_ast_type_guard as i32,
-            &mut guard,
-            gt as isize,
-            term,
-        )
-    } {
-        panic!("clingo_ast_build() guard failed.");
-    }
+    // let term: Term = symbolic_term.into();
+    // let mut guard = std::ptr::null_mut();
+    // if !unsafe {
+    //     clingo_ast_build(
+    //         clingo_ast_type_e_clingo_ast_type_guard as i32,
+    //         &mut guard,
+    //         gt as isize,
+    //         term.ast,
+    //     )
+    // } {
+    //     panic!("clingo_ast_build() guard failed.");
+    // }
+    // let _ = gt;
+    // let _ = term;
+    // let _ = symbolic_term;
 
-    let guard = match NonNull::new(guard) {
-        Some(ast) => Ok(Guard {
-            ast: AST {
-                ptr: ast,
-                _lifetime: PhantomData,
-            },
-        }),
-        None => Err(()),
-    };
-    let guard = guard.unwrap();
-    // let guard = guard(gt, symbolic_term).unwrap();
+    // let guard = match NonNull::new(guard) {
+    //     Some(ast) => Ok(Guard {
+    //         ast: AST {
+    //             ptr: ast,
+    //             _lifetime: PhantomData,
+    //         },
+    //     }),
+    //     None => Err(()),
+    // };
+    // let guard = guard.unwrap();
+    let guard = xguard(gt, symbolic_term).unwrap();
+    // let guard = clingo::ast::guard(gt, symbolic_term).unwrap();
 
     let mut size: usize = 0;
     if !unsafe { clingo_ast_to_string_size(guard.ast.ptr.as_ptr(), &mut size) } {