Improved try_macro_suggestion function

Author: Duddino

src/librustc_parse/parser/diagnostics.rs

@@ -1071,17 +1071,15 @@ impl<'a> Parser<'a> {
             self.bump(); //remove )
             let mut err = self.struct_span_err(lo.to(hi), "use of deprecated `try` macro");
             err.note("in the 2018 edition `try` is a reserved keyword, and the `try!()` macro is deprecated");
+            let prefix = if is_empty { "" } else { "alternatively, " };
             if !is_empty {
                 err.multipart_suggestion(
                     "you can use the `?` operator instead",
                     vec![(try_span, "".to_owned()), (hi, "?".to_owned())],
                     Applicability::MachineApplicable,
                 );
-                err.span_suggestion(lo.shrink_to_lo(), "alternatively, you can still access the deprecated `try!()` macro using the \"raw identifier\" syntax", "r#".to_string(), Applicability::MachineApplicable);
-            } else {
-                //if the try! macro is empty, it isn't possible to suggest something using the `?` operator
-                err.span_suggestion(lo.shrink_to_lo(), "you can still access the deprecated `try!()` macro using the \"raw identifier\" syntax", "r#".to_string(), Applicability::MachineApplicable);
             }
+            err.span_suggestion(lo.shrink_to_lo(), &format!("{}you can still access the deprecated `try!()` macro using the \"raw identifier\" syntax", prefix), "r#".to_string(), Applicability::MachineApplicable);
             err.emit();
             Ok(self.mk_expr_err(lo.to(hi)))
         } else {