modify code

[rust.git] / clippy_lints / src / to_string_in_display.rs

diff --git a/clippy_lints/src/to_string_in_display.rs b/clippy_lints/src/to_string_in_display.rs
index fa508df865e48af4a01b79866769aee3395f5dc7..03060d78fc5af39d325068a721a991b9e96a7e83 100644 (file)
--- a/clippy_lints/src/to_string_in_display.rs
+++ b/clippy_lints/src/to_string_in_display.rs
@@ -1,20 +1,21 @@
-use crate::utils::{match_def_path, match_trait_method, paths, span_lint};
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::{is_diag_trait_item, match_def_path, path_to_local_id, paths};
 use if_chain::if_chain;
-use rustc_hir::def::Res;
 use rustc_hir::{Expr, ExprKind, HirId, Impl, ImplItem, ImplItemKind, Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::symbol::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for uses of `to_string()` in `Display` traits.
+    /// ### What it does
+    /// Checks for uses of `to_string()` in `Display` traits.
     ///
-    /// **Why is this bad?** Usually `to_string` is implemented indirectly
+    /// ### Why is this bad?
+    /// Usually `to_string` is implemented indirectly
     /// via `Display`. Hence using it while implementing `Display` would
     /// lead to infinite recursion.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     ///
     /// ```rust
     /// use std::fmt;
@@ -38,6 +39,7 @@
     ///     }
     /// }
     /// ```
+    #[clippy::version = "1.48.0"]
     pub TO_STRING_IN_DISPLAY,
     correctness,
     "`to_string` method used while implementing `Display` trait"
@@ -89,14 +91,13 @@ fn check_impl_item(&mut self, cx: &LateContext<'_>, impl_item: &ImplItem<'_>) {
 
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
         if_chain! {
-            if let ExprKind::MethodCall(ref path, _, args, _) = expr.kind;
-            if path.ident.name == sym!(to_string);
-            if match_trait_method(cx, expr, &paths::TO_STRING);
             if self.in_display_impl;
-            if let ExprKind::Path(ref qpath) = args[0].kind;
-            if let Res::Local(hir_id) = cx.qpath_res(qpath, args[0].hir_id);
             if let Some(self_hir_id) = self.self_hir_id;
-            if hir_id == self_hir_id;
+            if let ExprKind::MethodCall(path, [ref self_arg, ..], _) = expr.kind;
+            if path.ident.name == sym!(to_string);
+            if let Some(expr_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+            if is_diag_trait_item(cx, expr_def_id, sym::ToString);
+            if path_to_local_id(self_arg, self_hir_id);
             then {
                 span_lint(
                     cx,