Address review comments

Author: lukaslueg

clippy_lints/src/size_of_ref.rs

@@ -1,5 +1,4 @@
-use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::ty::peel_mid_ty_refs;
+use clippy_utils::{diagnostics::span_lint_and_help, path_def_id, ty::peel_mid_ty_refs};
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -13,9 +12,9 @@ declare_clippy_lint! {
     ///
     /// ### Why is this bad?
     ///
-    /// The result of calling `size_of_val()` with a reference to a reference
-    /// as the argument will be the size of any generic reference-type, not
-    /// the size of the value behind the reference.
+    /// Calling `size_of_val()` with a reference to a reference as the argument
+    /// yields the size of the reference-type, not the size of the value behind
+    /// the reference.
     ///
     /// ### Example
     /// ```rust
@@ -25,10 +24,10 @@ declare_clippy_lint! {
     ///
     /// impl Foo {
     ///     fn size(&self) -> usize {
-    ///         // Note that `&self` as an argument is a `&&Foo`: Bacause `self`
-    ///         // is already a reference, `&self` is a double-reference,
-    ///         // and the return value of `size_of_val()` therefor is the
-    ///         // size of any generic reference-type.
+    ///         // Note that `&self` as an argument is a `&&Foo`: Because `self`
+    ///         // is already a reference, `&self` is a double-reference.
+    ///         // The return value of `size_of_val()` therefor is the
+    ///         // size of the reference-type, not the size of `self`.
     ///         std::mem::size_of_val(&self)
     ///     }
     /// }
@@ -48,16 +47,15 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.67.0"]
     pub SIZE_OF_REF,
-    correctness,
+    suspicious,
     "Argument to `std::mem::size_of_val()` is a double-reference, which is almost certainly unintended"
 }
 declare_lint_pass!(SizeOfRef => [SIZE_OF_REF]);
 
 impl LateLintPass<'_> for SizeOfRef {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &'_ Expr<'_>) {
         if let ExprKind::Call(path, [arg]) = expr.kind
-            && let ExprKind::Path(ref qpath) = path.kind
-            && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
+            && let Some(def_id) = path_def_id(cx, path)
             && cx.tcx.is_diagnostic_item(sym::mem_size_of_val, def_id)
             && let arg_ty = cx.typeck_results().expr_ty(arg)
             && peel_mid_ty_refs(arg_ty).1 > 1