Update nightly libsyntax api for parsing an expr
diff --git a/tests/common/parse.rs b/tests/common/parse.rs
index 31c2759..3f472f4 100644
--- a/tests/common/parse.rs
+++ b/tests/common/parse.rs
@@ -26,11 +26,11 @@
     match panic::catch_unwind(|| {
         let sess = ParseSess::new(FilePathMapping::empty());
         sess.span_diagnostic.set_continue_after_error(false);
-        let e = parse::parse_expr_from_source_str(
+        let e = parse::new_parser_from_source_str(
+            &sess,
             FileName::Custom("test_precedence".to_string()),
             input.to_string(),
-            &sess,
-        );
+        ).parse_expr();
         Some(match e {
             Ok(expr) => expr,
             Err(mut diagnostic) => {