fix path.ident.name does not point to the name of the function applied

Author: jonboh

clippy_lints/src/unnecessary_map_on_constructor.rs

@@ -73,12 +73,13 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryMapOnConstructor {
             }
 
             if let Some(map_arg) = args.get(0)
-                && let hir::ExprKind::Path(_) = map_arg.kind
+                && let hir::ExprKind::Path(fun) = map_arg.kind
             {
                 if map_arg.span.from_expansion() {
                     return;
                 }
                 let mut applicability = Applicability::MachineApplicable;
+                let fun_snippet = snippet_with_applicability(cx, fun.span(), "_", &mut applicability);
                 let constructor_snippet =
                     snippet_with_applicability(cx, constructor_path.span(), "_", &mut applicability);
                 let constructor_arg_snippet =
@@ -87,9 +88,9 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryMapOnConstructor {
                     cx,
                     UNNECESSARY_MAP_ON_CONSTRUCTOR,
                     expr.span,
-                    &format!("unnecessary {} on contstuctor {constructor_snippet}(_)", path.ident.name),
+                    &format!("unnecessary {fun_snippet} on contstuctor {constructor_snippet}(_)"),
                     "try",
-                    format!("{constructor_snippet}({}({constructor_arg_snippet}))", path.ident.name),
+                    format!("{constructor_snippet}({fun_snippet}({constructor_arg_snippet}))"),
                     applicability,
                 );
             }