Don’t use {:?} and use span_suggestion in TOPLEVEL_REF_ARG

Author: mcarton

src/misc.rs

@@ -11,7 +11,7 @@ use rustc::middle::const_eval::eval_const_expr_partial;
 use rustc::middle::const_eval::EvalHint::ExprTypeChecked;
 
 use utils::{get_item_name, match_path, snippet, get_parent_expr, span_lint};
-use utils::{span_help_and_lint, walk_ptrs_ty, is_integer_literal, implements_trait};
+use utils::{span_lint_and_then, walk_ptrs_ty, is_integer_literal, implements_trait};
 
 /// **What it does:** This lint checks for function arguments and let bindings denoted as `ref`.
 ///
@@ -62,16 +62,22 @@ impl LateLintPass for TopLevelRefPass {
             let Some(ref init) = l.init
             ], {
                 let tyopt = if let Some(ref ty) = l.ty {
-                    format!(": {:?} ", ty)
+                    format!(": {}", snippet(cx, ty.span, "_"))
                 } else {
                     "".to_owned()
                 };
-                span_help_and_lint(cx,
+                span_lint_and_then(cx,
                     TOPLEVEL_REF_ARG,
                     l.pat.span,
                     "`ref` on an entire `let` pattern is discouraged, take a reference with & instead",
-                    &format!("try `let {} {}= &{};`", snippet(cx, i.span, "_"),
-                             tyopt, snippet(cx, init.span, "_"))
+                    |db| {
+                        db.span_suggestion(s.span,
+                                           "try",
+                                           format!("let {}{} = &{};",
+                                                   snippet(cx, i.span, "_"),
+                                                   tyopt,
+                                                   snippet(cx, init.span, "_")));
+                    }
                 );
             }
         };

tests/compile-fail/toplevel_ref_arg.rs

@@ -15,11 +15,15 @@ fn main() {
   let y = |ref x| { println!("{:?}", x) };
   y(1u8);
 
-  let ref x = 1; //~ ERROR `ref` on an entire `let` pattern is discouraged
-                 //~^ HELP try `let x = &1;`
+  let ref x = 1;
+  //~^ ERROR `ref` on an entire `let` pattern is discouraged
+  //~| HELP try
+  //~| SUGGESTION let x = &1;
 
-  let ref y = (&1, 2); //~ ERROR `ref` on an entire `let` pattern is discouraged
-                 //~^ HELP try `let y = &(&1, 2);`
+  let ref y : (&_, u8) = (&1, 2);
+  //~^ ERROR `ref` on an entire `let` pattern is discouraged
+  //~| HELP try
+  //~| SUGGESTION let y: (&_, u8) = &(&1, 2);
 
   let (ref x, _) = (1,2); // okay, not top level
   println!("The answer is {}.", x);