diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 8498730b6e4..c99df255dd7 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -31630,7 +31630,10 @@ type_targs_deducible_from (tree tmpl, tree type)
 	 per alias_ctad_tweaks.  */
       tparms = INNERMOST_TEMPLATE_PARMS (TREE_PURPOSE (tmpl));
       ttype = TREE_VALUE (tmpl);
-      tmpl = TI_TEMPLATE (TYPE_TEMPLATE_INFO_MAYBE_ALIAS (ttype));
+      tree ti = TYPE_TEMPLATE_INFO_MAYBE_ALIAS (ttype);
+      if (!ti)
+	return NULL_TREE;
+      tmpl = TI_TEMPLATE (ti);
     }
 
   int len = TREE_VEC_LENGTH (tparms);
diff --git a/gcc/testsuite/g++.dg/cpp23/class-deduction-inherited-ice.C b/gcc/testsuite/g++.dg/cpp23/class-deduction-inherited-ice.C
new file mode 100644
index 00000000000..6724ce303d8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/class-deduction-inherited-ice.C
@@ -0,0 +1,34 @@
+// { dg-do compile { target c++23 } }
+// PR c++/122070
+
+namespace std {
+    template<typename T, T v> struct integral_constant { static constexpr T value = v; };
+    using size_t = decltype(sizeof(0));
+
+    template<typename CharT>
+    struct basic_string_view {
+        const CharT* ptr;
+        size_t len;
+        constexpr basic_string_view(const CharT* p) : ptr(p), len(0) { while (p && p[len]) ++len; }
+    };
+    using string_view = basic_string_view<char>;
+}
+
+template<std::size_t N>
+struct sized_string_view: std::string_view {
+    using std::string_view::string_view;
+};
+template<std::size_t N>
+sized_string_view(const char (&str)[N]) -> sized_string_view<N - 1>;
+
+
+constexpr auto string_builder(auto first, auto second, auto... trailing) {
+    constexpr auto is_last = sizeof...(trailing) == 0;
+    auto buffer = 1;
+    if constexpr (is_last) {
+        return buffer;
+    } else
+        return string_builder(buffer, trailing...);
+}
+
+constexpr auto copyright = string_builder(sized_string_view("a"), sized_string_view("b"), sized_string_view("c"));