use is_empty and feature(exact_size_is_empty)

Author: rchaser53

src/lib.rs

@@ -1,4 +1,5 @@
 #![deny(rust_2018_idioms)]
+#![feature(exact_size_is_empty)]
 
 #[macro_use]
 extern crate derive_new;

src/types.rs

@@ -318,7 +318,7 @@ where
     };
 
     let list_lo = context.snippet_provider.span_after(span, "(");
-    let (list_str, tactic) = if inputs.len() == 0 {
+    let (list_str, tactic) = if inputs.is_empty() {
         let tactic = get_tactics(&Vec::<ListItem>::new(), &output, &shape);
         let list_hi = context.snippet_provider.span_before_last(span, ")");
         let comment = context