Use Sugg interface for suggestion

Author: bluebear94

clippy_lints/src/default_box_assignments.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::is_default_equivalent_call;
-use clippy_utils::source::snippet;
+use clippy_utils::sugg::Sugg;
 use clippy_utils::ty::implements_trait;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, LangItem};
@@ -45,13 +45,17 @@ impl LateLintPass<'_> for DefaultBoxAssignments {
                     expr.span,
                     "assigning `Default::default()` to `Box<T>`",
                     |diag| {
-                        let suggestion = format!("*({}) = Default::default()", snippet(cx, lhs.span, "_"));
+                        let mut app = Applicability::MachineApplicable;
+                        let suggestion = format!(
+                            "{} = Default::default()",
+                            Sugg::hir_with_applicability(cx, lhs, "_", &mut app).deref()
+                        );
 
                         diag.note("this creates a needless allocation").span_suggestion(
                             expr.span,
                             "assign to the inner value",
                             suggestion,
-                            Applicability::MaybeIncorrect,
+                            app,
                         );
                     },
                 );

tests/ui/default_box_assignments.fixed

@@ -8,9 +8,9 @@ macro_rules! create_default {
 
 fn main() {
     let mut b = Box::new(1u32);
-    *(b) = Default::default();
+    *b = Default::default();
     //~^ default_box_assignments
-    *(b) = Default::default();
+    *b = Default::default();
     //~^ default_box_assignments
 
     // No lint for assigning to the storage

tests/ui/default_box_assignments.stderr

@@ -2,7 +2,7 @@ error: assigning `Default::default()` to `Box<T>`
   --> tests/ui/default_box_assignments.rs:11:5
    |
 LL |     b = Default::default();
-   |     ^^^^^^^^^^^^^^^^^^^^^^ help: assign to the inner value: `*(b) = Default::default()`
+   |     ^^^^^^^^^^^^^^^^^^^^^^ help: assign to the inner value: `*b = Default::default()`
    |
    = note: this creates a needless allocation
    = note: `-D clippy::default-box-assignments` implied by `-D warnings`
@@ -12,7 +12,7 @@ error: assigning `Default::default()` to `Box<T>`
   --> tests/ui/default_box_assignments.rs:13:5
    |
 LL |     b = Box::default();
-   |     ^^^^^^^^^^^^^^^^^^ help: assign to the inner value: `*(b) = Default::default()`
+   |     ^^^^^^^^^^^^^^^^^^ help: assign to the inner value: `*b = Default::default()`
    |
    = note: this creates a needless allocation