-use crate::utils::{match_def_path, match_trait_method, path_to_local_id, 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::{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;
/// }
/// }
/// ```
+ #[clippy::version = "1.48.0"]
pub TO_STRING_IN_DISPLAY,
correctness,
"`to_string` method used while implementing `Display` trait"
if_chain! {
if self.in_display_impl;
if let Some(self_hir_id) = self.self_hir_id;
- if let ExprKind::MethodCall(ref path, _, args, _) = expr.kind;
+ if let ExprKind::MethodCall(path, [ref self_arg, ..], _) = expr.kind;
if path.ident.name == sym!(to_string);
- if match_trait_method(cx, expr, &paths::TO_STRING);
- if path_to_local_id(&args[0], self_hir_id);
+ 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,