[clang] Fix a crash in debug mode

Resolves Issue #35603

This bug was caused due to the assertions being too strict,
loosened by stripping qualifiers from the base class but not
from the type of the initializer.

Added Release Notes for the same.

Author: Rajveer100

clang/docs/ReleaseNotes.rst

@@ -486,6 +486,9 @@ Bug Fixes to C++ Support
 - Fixed a bug that prevented member function templates of class templates declared with a deduced return type
   from being explicitly specialized for a given implicit instantiation of the class template.
 
+- Fix crash when inheriting from a cv-qualified type. Fixes:
+  (`#35603 <https://github.com/llvm/llvm-project/issues/35603>`_)
+
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 - Clang now properly preserves ``FoundDecls`` within a ``ConceptReference``. (#GH82628)

clang/lib/AST/ExprConstant.cpp

@@ -6456,7 +6456,7 @@ static bool HandleConstructorCall(const Expr *E, const LValue &This,
       // Non-virtual base classes are initialized in the order in the class
       // definition. We have already checked for virtual base classes.
       assert(!BaseIt->isVirtual() && "virtual base for literal type");
-      assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&
+      assert(Info.Ctx.hasSameUnqualifiedType(BaseIt->getType(), BaseType) &&
              "base class initializers not in expected order");
       ++BaseIt;
 #endif

clang/test/Sema/GH70594.cpp

@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 %s -verify
+// RUN: %clang_cc1 -fsyntax-only -std=c++23 %s -verify
+
+// expected-no-diagnostics
+
+struct A {};
+using CA = const A;
+
+struct S1 : CA {
+  constexpr S1() : CA() {}
+};
+
+struct S2 : A {
+  constexpr S2() : CA() {}
+};
+
+struct S3 : CA {
+  constexpr S3() : A() {}
+};
+
+struct Int {};
+
+template <class _Hp>
+struct __tuple_leaf : _Hp {
+  constexpr __tuple_leaf() : _Hp() {}
+};
+
+constexpr __tuple_leaf<const Int> t;