remove now dead code in ASSERTIONS_ON_CONSTANTS

cc rust-lang#11966

Author: tesuji

clippy_lints/src/assertions_on_constants.rs

@@ -1,8 +1,8 @@
-use clippy_utils::consts::{constant_with_source, Constant, ConstantSource};
+use clippy_utils::consts::{constant, Constant};
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::is_inside_always_const_context;
 use clippy_utils::macros::{find_assert_args, root_macro_call_first_node, PanicExpn};
-use rustc_hir::{Expr, Item, ItemKind, Node};
+use rustc_hir::Expr;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::declare_lint_pass;
 use rustc_span::sym;
@@ -47,17 +47,9 @@ impl<'tcx> LateLintPass<'tcx> for AssertionsOnConstants {
         let Some((condition, panic_expn)) = find_assert_args(cx, e, macro_call.expn) else {
             return;
         };
-        let Some((Constant::Bool(val), source)) = constant_with_source(cx, cx.typeck_results(), condition) else {
+        let Some(Constant::Bool(val)) = constant(cx, cx.typeck_results(), condition) else {
             return;
         };
-        if let ConstantSource::Constant = source
-            && let Node::Item(Item {
-                kind: ItemKind::Const(..),
-                ..
-            }) = cx.tcx.parent_hir_node(e.hir_id)
-        {
-            return;
-        }
         if val {
             span_lint_and_help(
                 cx,