Use Sugg for redundant_closure_call implementation

Author: AaronC81

clippy_lints/src/redundant_closure_call.rs

@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
-use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::sugg::Sugg;
 use if_chain::if_chain;
 use rustc_ast::ast;
 use rustc_ast::visit as ast_visit;
@@ -81,18 +81,19 @@ impl EarlyLintPass for RedundantClosureCall {
                         "try not to call a closure in the expression where it is declared",
                         |diag| {
                             if decl.inputs.is_empty() {
-                                let mut app = Applicability::MachineApplicable;
-                                let mut hint =
-                                    snippet_with_applicability(cx, block.span, "..", &mut app).into_owned();
+                                let app = Applicability::MachineApplicable;
+                                let mut hint = Sugg::ast(cx, block, "..");
+
                                 if r#async.is_async() {
-                                    if let ast::ExprKind::Block(_, _) = block.kind {
-                                        hint = format!("async {}", hint);
-                                    } else {
-                                        // `async x` is a syntax error, so it becomes `async { x }`
-                                        hint = format!("async {{ {} }}", hint);
+                                    // `async x` is a syntax error, so it becomes `async { x }`
+                                    if !matches!(block.kind, ast::ExprKind::Block(_, _)) {
+                                        hint = hint.blockify();
                                     }
+
+                                    hint = hint.asyncify();
                                 }
-                                diag.span_suggestion(expr.span, "try doing something like", hint, app);
+
+                                diag.span_suggestion(expr.span, "try doing something like", hint.to_string(), app);
                             }
                         },
                     );