Rm diagnostic item, use lang item

Author: fee1-dead

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -464,7 +464,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     ref_cnt += 1;
                 }
                 if let ty::Adt(adt, _) = peeled.kind()
-                    && self.tcx.is_diagnostic_item(sym::String, adt.did())
+                    && Some(adt.did()) == self.tcx.lang_items().string()
                 {
                     err.span_suggestion_verbose(
                         expr.span.shrink_to_hi(),

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -817,10 +817,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 ty.is_str()
                                     || matches!(
                                         ty.kind(),
-                                        ty::Adt(adt, _) if self.tcx.is_diagnostic_item(sym::String, adt.did())
+                                        ty::Adt(adt, _) if Some(adt.did()) == self.tcx.lang_items().string()
                                     )
                             }
-                            ty::Adt(adt, _) => self.tcx.is_diagnostic_item(sym::String, adt.did()),
+                            ty::Adt(adt, _) => Some(adt.did()) == self.tcx.lang_items().string(),
                             _ => false,
                         };
                         if is_string_or_ref_str && item_name.name == sym::iter {

compiler/rustc_hir_typeck/src/op.rs

@@ -556,9 +556,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let rm_borrow_msg = "remove the borrow to obtain an owned `String`";
         let to_owned_msg = "create an owned `String` from a string reference";
 
+        let string_type = self.tcx.lang_items().string();
         let is_std_string = |ty: Ty<'tcx>| {
-            ty.ty_adt_def()
-                .map_or(false, |ty_def| self.tcx.is_diagnostic_item(sym::String, ty_def.did()))
+            ty.ty_adt_def().map_or(false, |ty_def| Some(ty_def.did()) == string_type)
         };
 
         match (lhs_ty.kind(), rhs_ty.kind()) {

compiler/rustc_lint/src/non_fmt_panic.rs

@@ -148,7 +148,7 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
                 ty::Ref(_, r, _) if *r.kind() == ty::Str,
             ) || matches!(
                 ty.ty_adt_def(),
-                Some(ty_def) if cx.tcx.is_diagnostic_item(sym::String, ty_def.did()),
+                Some(ty_def) if Some(ty_def.did()) == cx.tcx.lang_items().string(),
             );
 
             let infcx = cx.tcx.infer_ctxt().build();

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -1705,7 +1705,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 ty::Bool => Some(0),
                 ty::Char => Some(1),
                 ty::Str => Some(2),
-                ty::Adt(def, _) if tcx.is_diagnostic_item(sym::String, def.did()) => Some(2),
+                ty::Adt(def, _) if Some(def.did()) == tcx.lang_items().string() => Some(2),
                 ty::Int(..)
                 | ty::Uint(..)
                 | ty::Float(..)

library/alloc/src/string.rs

@@ -362,9 +362,8 @@ use crate::vec::Vec;
 /// [`Deref`]: core::ops::Deref "ops::Deref"
 /// [`as_str()`]: String::as_str
 #[derive(PartialOrd, Eq, Ord)]
-#[cfg_attr(not(test), rustc_diagnostic_item = "String")]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[cfg_attr(not(bootstrap), lang = "String")]
+#[cfg_attr(all(not(bootstrap), not(test)), lang = "String")]
 pub struct String {
     vec: Vec<u8>,
 }

src/tools/clippy/clippy_lints/src/format.rs

@@ -73,7 +73,7 @@ impl<'tcx> LateLintPass<'tcx> for UselessFormat {
                 if format_args.format_string.parts == [kw::Empty];
                 if arg.format.is_default();
                 if match cx.typeck_results().expr_ty(value).peel_refs().kind() {
-                    ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(sym::String, adt.did()),
+                    ty::Adt(adt, _) => Some(adt.did()) == cx.tcx.lang_items().string(),
                     ty::Str => true,
                     _ => false,
                 };

src/tools/clippy/clippy_lints/src/format_push_string.rs

@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::ty::is_type_lang_item;
 use clippy_utils::{match_def_path, paths, peel_hir_expr_refs};
-use rustc_hir::{BinOpKind, Expr, ExprKind};
+use rustc_hir::{BinOpKind, Expr, ExprKind, LangItem};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
@@ -41,7 +41,7 @@ declare_clippy_lint! {
 declare_lint_pass!(FormatPushString => [FORMAT_PUSH_STRING]);
 
 fn is_string(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
-    is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(e).peel_refs(), sym::String)
+    is_type_lang_item(cx, cx.typeck_results().expr_ty(e).peel_refs(), LangItem::String)
 }
 fn is_format(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
     if let Some(macro_def_id) = e.span.ctxt().outer_expn_data().macro_def_id {

src/tools/clippy/clippy_lints/src/from_str_radix_10.rs

@@ -1,10 +1,10 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::is_integer_literal;
 use clippy_utils::sugg::Sugg;
-use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::ty::{is_type_diagnostic_item, is_type_lang_item};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
-use rustc_hir::{def, Expr, ExprKind, PrimTy, QPath, TyKind};
+use rustc_hir::{def, Expr, ExprKind, LangItem, PrimTy, QPath, TyKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::Ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -98,5 +98,5 @@ impl<'tcx> LateLintPass<'tcx> for FromStrRadix10 {
 
 /// Checks if a Ty is `String` or `&str`
 fn is_ty_stringish(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
-    is_type_diagnostic_item(cx, ty, sym::String) || is_type_diagnostic_item(cx, ty, sym::str)
+    is_type_lang_item(cx, ty, LangItem::String) || is_type_diagnostic_item(cx, ty, sym::str)
 }

src/tools/clippy/clippy_lints/src/inherent_to_string.rs

@@ -1,8 +1,8 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
+use clippy_utils::ty::{implements_trait, is_type_lang_item};
 use clippy_utils::{return_ty, trait_ref_of_method};
 use if_chain::if_chain;
-use rustc_hir::{GenericParamKind, ImplItem, ImplItemKind};
+use rustc_hir::{GenericParamKind, ImplItem, ImplItemKind, LangItem};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
@@ -105,7 +105,7 @@ impl<'tcx> LateLintPass<'tcx> for InherentToString {
             if impl_item.generics.params.iter().all(|p| matches!(p.kind, GenericParamKind::Lifetime { .. }));
 
             // Check if return type is String
-            if is_type_diagnostic_item(cx, return_ty(cx, impl_item.hir_id()), sym::String);
+            if is_type_lang_item(cx, return_ty(cx, impl_item.hir_id()), LangItem::String);
 
             // Filters instances of to_string which are required by a trait
             if trait_ref_of_method(cx, impl_item.owner_id.def_id).is_none();