Remove is_diag_item_method

Author: Jarcho

clippy_lints/src/lines_filter_map_ok.rs

@@ -2,7 +2,7 @@ use clippy_config::Conf;
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::msrvs::{self, Msrv};
 use clippy_utils::res::{MaybeDef, MaybeResPath};
-use clippy_utils::{is_diag_item_method, is_trait_method, sym};
+use clippy_utils::{is_trait_method, sym};
 use rustc_errors::Applicability;
 use rustc_hir::{Body, Closure, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
@@ -120,10 +120,15 @@ fn should_lint(cx: &LateContext<'_>, args: &[Expr<'_>], method_name: Symbol) ->
                         params: [param], value, ..
                     } = cx.tcx.hir_body(*body)
                         && let ExprKind::MethodCall(method, receiver, [], _) = value.kind
-                        && receiver.res_local_id() == Some(param.pat.hir_id)
-                        && let Some(method_did) = cx.typeck_results().type_dependent_def_id(value.hir_id)
                     {
-                        is_diag_item_method(cx, method_did, sym::Result) && method.ident.name == sym::ok
+                        method.ident.name == sym::ok
+                            && receiver.res_local_id() == Some(param.pat.hir_id)
+                            && cx
+                                .typeck_results()
+                                .type_dependent_def_id(value.hir_id)
+                                .opt_parent(cx)
+                                .opt_impl_ty(cx)
+                                .is_diag_item(cx, sym::Result)
                     } else {
                         false
                     }

clippy_lints/src/methods/manual_inspect.rs

@@ -4,7 +4,7 @@ use clippy_utils::res::{MaybeDef, MaybeResPath};
 use clippy_utils::source::{IntoSpan, SpanRangeExt};
 use clippy_utils::ty::get_field_by_name;
 use clippy_utils::visitors::{for_each_expr, for_each_expr_without_closures};
-use clippy_utils::{ExprUseNode, expr_use_ctxt, is_diag_item_method, sym};
+use clippy_utils::{ExprUseNode, expr_use_ctxt, sym};
 use core::ops::ControlFlow;
 use rustc_errors::Applicability;
 use rustc_hir::{BindingMode, BorrowKind, ByRef, ClosureKind, Expr, ExprKind, Mutability, Node, PatKind};
@@ -21,7 +21,8 @@ pub(crate) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, arg: &Expr<'_>, name:
         && let typeck = cx.typeck_results()
         && let Some(fn_def) = typeck.type_dependent_def(expr.hir_id)
         && (fn_def.assoc_fn_parent(cx).is_diag_item(cx, sym::Iterator)
-            || ((is_diag_item_method(cx, fn_def.1, sym::Option) || is_diag_item_method(cx, fn_def.1, sym::Result))
+            || ((fn_def.assoc_fn_parent(cx).opt_impl_ty(cx).is_diag_item(cx, sym::Option)
+                || fn_def.assoc_fn_parent(cx).opt_impl_ty(cx).is_diag_item(cx, sym::Result))
                 && msrv.meets(cx, msrvs::OPTION_RESULT_INSPECT)))
         && let body = cx.tcx.hir_body(c.body)
         && let [param] = body.params

clippy_lints/src/methods/str_splitn.rs

@@ -1,11 +1,11 @@
 use clippy_utils::consts::{ConstEvalCtxt, Constant};
 use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
 use clippy_utils::msrvs::{self, Msrv};
-use clippy_utils::res::MaybeResPath;
+use clippy_utils::res::{MaybeDef, MaybeResPath};
 use clippy_utils::source::snippet_with_context;
 use clippy_utils::usage::local_used_after_expr;
 use clippy_utils::visitors::{Descend, for_each_expr};
-use clippy_utils::{is_diag_item_method, paths, sym};
+use clippy_utils::{paths, sym};
 use core::ops::ControlFlow;
 use rustc_errors::Applicability;
 use rustc_hir::{
@@ -351,7 +351,9 @@ fn parse_iter_usage<'tcx>(
                     && cx
                         .typeck_results()
                         .type_dependent_def_id(e.hir_id)
-                        .is_some_and(|id| is_diag_item_method(cx, id, sym::Option)) =>
+                        .opt_parent(cx)
+                        .opt_impl_ty(cx)
+                        .is_diag_item(cx, sym::Option) =>
             {
                 (Some(UnwrapKind::Unwrap), e.span)
             },

clippy_utils/src/lib.rs

@@ -356,16 +356,6 @@ pub fn is_inherent_method_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     }
 }
 
-/// Checks if a method is defined in an impl of a diagnostic item
-pub fn is_diag_item_method(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
-    if let Some(impl_did) = cx.tcx.impl_of_assoc(def_id)
-        && let Some(adt) = cx.tcx.type_of(impl_did).instantiate_identity().ty_adt_def()
-    {
-        return cx.tcx.is_diagnostic_item(diag_item, adt.did());
-    }
-    false
-}
-
 /// Checks if the method call given in `expr` belongs to the given trait.
 pub fn is_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
     cx.typeck_results()