Factor out expr_path_res

4 files changed, 11 insertions, 24 deletions

diff --git a/clippy_lints/src/misc.rs b/clippy_lints/src/misc.rs
index 3918bdbdf43..ac82dd306a5 100644
--- a/clippy_lints/src/misc.rs
+++ b/clippy_lints/src/misc.rs
@@ -20,8 +20,8 @@ use rustc_span::symbol::sym;
 use clippy_utils::consts::{constant, Constant};
 use clippy_utils::sugg::Sugg;
 use clippy_utils::{
-    expr_path_res, get_item_name, get_parent_expr, in_constant, is_diag_trait_item, is_integer_const, iter_input_pats,
-    last_path_segment, match_any_def_paths, paths, unsext, SpanlessEq,
+    get_item_name, get_parent_expr, in_constant, is_diag_trait_item, is_integer_const, iter_input_pats,
+    last_path_segment, match_any_def_paths, path_def_id, paths, unsext, SpanlessEq,
 };
 
 declare_clippy_lint! {
@@ -583,8 +583,7 @@ fn check_to_owned(cx: &LateContext<'_>, expr: &Expr<'_>, other: &Expr<'_>, left:
             )
         },
         ExprKind::Call(path, [arg]) => {
-            if expr_path_res(cx, path)
-                .opt_def_id()
+            if path_def_id(cx, path)
                 .and_then(|id| match_any_def_paths(cx, id, &[&paths::FROM_STR_METHOD, &paths::FROM_FROM]))
                 .is_some()
             {
diff --git a/clippy_lints/src/ptr.rs b/clippy_lints/src/ptr.rs
index b5d65542de0..26717c0c0fd 100644
--- a/clippy_lints/src/ptr.rs
+++ b/clippy_lints/src/ptr.rs
@@ -4,7 +4,8 @@ use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_and_the
 use clippy_utils::source::snippet_opt;
 use clippy_utils::ty::expr_sig;
 use clippy_utils::{
-    expr_path_res, get_expr_use_or_unification_node, is_lint_allowed, match_any_diagnostic_items, path_to_local, paths,
+    expr_path_res, get_expr_use_or_unification_node, is_lint_allowed, is_lint_allowed, match_any_diagnostic_items,
+    path_def_id, path_to_local, paths, paths,
 };
 use if_chain::if_chain;
 use rustc_errors::Applicability;
@@ -665,8 +666,8 @@ fn get_rptr_lm<'tcx>(ty: &'tcx hir::Ty<'tcx>) -> Option<(&'tcx Lifetime, Mutabil
 
 fn is_null_path(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     if let ExprKind::Call(pathexp, []) = expr.kind {
-        expr_path_res(cx, pathexp).opt_def_id().map_or(false, |id| {
-            match_any_diagnostic_items(cx, id, &[sym::ptr_null, sym::ptr_null_mut]).is_some()
+        path_def_id(cx, pathexp).map_or(false, |id| {
+            matches!(cx.tcx.get_diagnostic_name(id), Some(sym::ptr_null | sym::ptr_null_mut))
         })
     } else {
         false
diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs
index 3df7af601cf..eeadc6d4dda 100644
--- a/clippy_utils/src/lib.rs
+++ b/clippy_utils/src/lib.rs
@@ -357,15 +357,6 @@ pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
     }
 }
 
-/// If the expression is a path, resolve it. Otherwise, return `Res::Err`.
-pub fn expr_path_res(cx: &LateContext<'_>, expr: &Expr<'_>) -> Res {
-    if let ExprKind::Path(p) = &expr.kind {
-        cx.qpath_res(p, expr.hir_id)
-    } else {
-        Res::Err
-    }
-}
-
 /// Resolves the path to a `DefId` and checks if it matches the given path.
 pub fn is_qpath_def_path(cx: &LateContext<'_>, path: &QPath<'_>, hir_id: HirId, segments: &[&str]) -> bool {
     cx.qpath_res(path, hir_id)
@@ -377,17 +368,13 @@ pub fn is_qpath_def_path(cx: &LateContext<'_>, path: &QPath<'_>, hir_id: HirId,
 ///
 /// Please use `is_expr_diagnostic_item` if the target is a diagnostic item.
 pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
-    expr_path_res(cx, expr)
-        .opt_def_id()
-        .map_or(false, |id| match_def_path(cx, id, segments))
+    path_def_id(cx, expr).map_or(false, |id| match_def_path(cx, id, segments))
 }
 
 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given
 /// diagnostic item.
 pub fn is_expr_diagnostic_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
-    expr_path_res(cx, expr)
-        .opt_def_id()
-        .map_or(false, |id| cx.tcx.is_diagnostic_item(diag_item, id))
+    path_def_id(cx, expr).map_or(false, |id| cx.tcx.is_diagnostic_item(diag_item, id))
 }
 
 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
diff --git a/clippy_utils/src/ty.rs b/clippy_utils/src/ty.rs
index d057da73302..aa3ea2d23da 100644
--- a/clippy_utils/src/ty.rs
+++ b/clippy_utils/src/ty.rs
@@ -20,7 +20,7 @@ use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::query::normalize::AtExt;
 use std::iter;
 
-use crate::{expr_path_res, match_def_path, must_use_attr};
+use crate::{match_def_path, must_use_attr, path_res};
 
 // Checks if the given type implements copy.
 pub fn is_copy<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
@@ -443,7 +443,7 @@ impl<'tcx> ExprFnSig<'tcx> {
 
 /// If the expression is function like, get the signature for it.
 pub fn expr_sig<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>) -> Option<ExprFnSig<'tcx>> {
-    if let Res::Def(DefKind::Fn | DefKind::Ctor(_, CtorKind::Fn) | DefKind::AssocFn, id) = expr_path_res(cx, expr) {
+    if let Res::Def(DefKind::Fn | DefKind::Ctor(_, CtorKind::Fn) | DefKind::AssocFn, id) = path_res(cx, expr) {
         Some(ExprFnSig::Sig(cx.tcx.fn_sig(id)))
     } else {
         let ty = cx.typeck_results().expr_ty_adjusted(expr).peel_refs();