Merge remote-tracking branch 'upstream/master' into rustup

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

diff --git a/clippy_lints/src/inherent_to_string.rs b/clippy_lints/src/inherent_to_string.rs
index b92a99488f9de80ed4f95fb70e431d7d21c01b50..b723d06a6881d27454b4d94a3b5aca6918748739 100644 (file)
--- a/clippy_lints/src/inherent_to_string.rs
+++ b/clippy_lints/src/inherent_to_string.rs
@@ -1,15 +1,16 @@
 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 rustc_hir::{ImplItem, ImplItemKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
 
 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,
+    get_trait_def_id, implements_trait, is_type_diagnostic_item, paths, return_ty, span_lint_and_help,
+    trait_ref_of_method,
 };
 
 declare_clippy_lint! {
-    /// **What id does:** Checks for the definition of inherent methods with a signature of `to_string(&self) -> String`.
+    /// **What it 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.
     ///
@@ -46,7 +47,7 @@
 }
 
 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.
+    /// **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.
     ///
     /// **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`.
     ///
@@ -87,27 +88,27 @@
     /// ```
     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 let ImplItemKind::Fn(ref signature, _) = impl_item.kind;
             if impl_item.ident.name.as_str() == "to_string";
             let decl = &signature.decl;
             if decl.implicit_self.has_implicit_self();
             if decl.inputs.len() == 1;
 
             // 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_type);
 
             // Filters instances of to_string which are required by a trait
             if trait_ref_of_method(cx, impl_item.hir_id).is_none();
@@ -119,18 +120,17 @@ fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, impl_item: &'tcx ImplI
     }
 }
 
-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 = 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,
@@ -138,10 +138,11 @@ fn show_lint(cx: &LateContext<'_, '_>, item: &ImplItem) {
                 "type `{}` implements inherent method `to_string(&self) -> String` which shadows the implementation of `Display`",
                 self_type.to_string()
             ),
+            None,
             &format!("remove the inherent method from type `{}`", self_type.to_string())
         );
     } else {
-        span_help_and_lint(
+        span_lint_and_help(
             cx,
             INHERENT_TO_STRING,
             item.span,
@@ -149,6 +150,7 @@ fn show_lint(cx: &LateContext<'_, '_>, item: &ImplItem) {
                 "implementation of inherent method `to_string(&self) -> String` for type `{}`",
                 self_type.to_string()
             ),
+            None,
             &format!("implement trait `Display` for type `{}` instead", self_type.to_string()),
         );
     }