+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
+use clippy_utils::{get_trait_def_id, paths, return_ty, trait_ref_of_method};
use if_chain::if_chain;
-use rustc::hir::{ImplItem, ImplItemKind};
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_lint_pass, declare_tool_lint};
-
-use crate::utils::{
- get_trait_def_id, implements_trait, match_type, paths, return_ty, span_help_and_lint, trait_ref_of_method,
- walk_ptrs_ty,
-};
+use rustc_hir::{ImplItem, ImplItemKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
declare_clippy_lint! {
- /// **What id does:** Checks for the definition of inherent methods with a signature of `to_string(&self) -> String`.
- ///
- /// **Why is this bad?** This method is also implicitly defined if a type implements the `Display` trait. As the functionality of `Display` is much more versatile, it should be preferred.
- ///
- /// **Known problems:** None
+ /// ### What it does
+ /// Checks for the definition of inherent methods with a signature of `to_string(&self) -> String`.
///
- /// ** Example:**
+ /// ### Why is this bad?
+ /// This method is also implicitly defined if a type implements the `Display` trait. As the functionality of `Display` is much more versatile, it should be preferred.
///
+ /// ### Example
/// ```rust
- /// // Bad
/// pub struct A;
///
/// impl A {
/// }
/// ```
///
+ /// Use instead:
/// ```rust
- /// // Good
/// use std::fmt;
///
/// pub struct A;
/// }
/// }
/// ```
+ #[clippy::version = "1.38.0"]
pub INHERENT_TO_STRING,
style,
"type implements inherent method `to_string()`, but should instead implement the `Display` trait"
}
declare_clippy_lint! {
- /// **What id does:** Checks for the definition of inherent methods with a signature of `to_string(&self) -> String` and if the type implementing this method also implements the `Display` trait.
- ///
- /// **Why is this bad?** This method is also implicitly defined if a type implements the `Display` trait. The less versatile inherent method will then shadow the implementation introduced by `Display`.
- ///
- /// **Known problems:** None
+ /// ### What it does
+ /// Checks for the definition of inherent methods with a signature of `to_string(&self) -> String` and if the type implementing this method also implements the `Display` trait.
///
- /// ** Example:**
+ /// ### Why is this bad?
+ /// This method is also implicitly defined if a type implements the `Display` trait. The less versatile inherent method will then shadow the implementation introduced by `Display`.
///
+ /// ### Example
/// ```rust
- /// // Bad
/// use std::fmt;
///
/// pub struct A;
/// }
/// ```
///
+ /// Use instead:
/// ```rust
- /// // Good
/// use std::fmt;
///
/// pub struct A;
/// }
/// }
/// ```
+ #[clippy::version = "1.38.0"]
pub INHERENT_TO_STRING_SHADOW_DISPLAY,
correctness,
- "type implements inherent method `to_string()`, which gets shadowed by the implementation of the `Display` trait "
+ "type implements inherent method `to_string()`, which gets shadowed by the implementation of the `Display` trait"
}
declare_lint_pass!(InherentToString => [INHERENT_TO_STRING, INHERENT_TO_STRING_SHADOW_DISPLAY]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InherentToString {
- fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, impl_item: &'tcx ImplItem) {
+impl<'tcx> LateLintPass<'tcx> for InherentToString {
+ fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &'tcx ImplItem<'_>) {
if impl_item.span.from_expansion() {
return;
}
if_chain! {
// Check if item is a method, called to_string and has a parameter 'self'
- if let ImplItemKind::Method(ref signature, _) = impl_item.kind;
- if impl_item.ident.name.as_str() == "to_string";
+ if let ImplItemKind::Fn(ref signature, _) = impl_item.kind;
+ if impl_item.ident.name == sym::to_string;
let decl = &signature.decl;
if decl.implicit_self.has_implicit_self();
if decl.inputs.len() == 1;
+ if impl_item.generics.params.is_empty();
// Check if return type is String
- if match_type(cx, return_ty(cx, impl_item.hir_id), &paths::STRING);
+ if is_type_diagnostic_item(cx, return_ty(cx, impl_item.hir_id()), sym::String);
// Filters instances of to_string which are required by a trait
- if trait_ref_of_method(cx, impl_item.hir_id).is_none();
+ if trait_ref_of_method(cx, impl_item.def_id).is_none();
then {
show_lint(cx, impl_item);
}
}
-fn show_lint(cx: &LateContext<'_, '_>, item: &ImplItem) {
- let display_trait_id =
- get_trait_def_id(cx, &["core", "fmt", "Display"]).expect("Failed to get trait ID of `Display`!");
+fn show_lint(cx: &LateContext<'_>, item: &ImplItem<'_>) {
+ let display_trait_id = get_trait_def_id(cx, &paths::DISPLAY_TRAIT).expect("Failed to get trait ID of `Display`!");
// Get the real type of 'self'
- let fn_def_id = cx.tcx.hir().local_def_id(item.hir_id);
- let self_type = cx.tcx.fn_sig(fn_def_id).input(0);
- let self_type = walk_ptrs_ty(self_type.skip_binder());
+ let self_type = cx.tcx.fn_sig(item.def_id).input(0);
+ let self_type = self_type.skip_binder().peel_refs();
// Emit either a warning or an error
if implements_trait(cx, self_type, display_trait_id, &[]) {
- span_help_and_lint(
+ span_lint_and_help(
cx,
INHERENT_TO_STRING_SHADOW_DISPLAY,
item.span,
&format!(
"type `{}` implements inherent method `to_string(&self) -> String` which shadows the implementation of `Display`",
- self_type.to_string()
+ self_type
),
- &format!("remove the inherent method from type `{}`", self_type.to_string())
+ None,
+ &format!("remove the inherent method from type `{}`", self_type),
);
} else {
- span_help_and_lint(
+ span_lint_and_help(
cx,
INHERENT_TO_STRING,
item.span,
&format!(
"implementation of inherent method `to_string(&self) -> String` for type `{}`",
- self_type.to_string()
+ self_type
),
- &format!("implement trait `Display` for type `{}` instead", self_type.to_string()),
+ None,
+ &format!("implement trait `Display` for type `{}` instead", self_type),
);
}
}
projects / rust.git / blobdiff