Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -86,6 +86,9 @@
   `Issue 57387 <https://github.com/llvm/llvm-project/issues/57387>`_.
 - Fix a crash when emitting a concept-related diagnostic. This fixes
   `Issue 57415 <https://github.com/llvm/llvm-project/issues/57415>`_.
+- Fix a crash when attempting to default a virtual constexpr non-special member
+  function in a derived class. This fixes
+  `Issue 57431 <https://github.com/llvm/llvm-project/issues/57431>`_
 
 
 Improvements to Clang's diagnostics
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -6954,7 +6954,8 @@
     // Define defaulted constexpr virtual functions that override a base class
     // function right away.
     // FIXME: We can defer doing this until the vtable is marked as used.
-    if (M->isDefaulted() && M->isConstexpr() && M->size_overridden_methods())
+    if (CSM != CXXInvalid && M->isDefaulted() && M->isConstexpr() &&
+        M->size_overridden_methods())
       DefineDefaultedFunction(*this, M, M->getLocation());
 
     if (!Incomplete)
Index: clang/test/SemaCXX/constant-expression-cxx2a.cpp
===================================================================
--- clang/test/SemaCXX/constant-expression-cxx2a.cpp
+++ clang/test/SemaCXX/constant-expression-cxx2a.cpp
@@ -1473,3 +1473,13 @@
   }
   static_assert(g()); // expected-error {{constant expression}} expected-note {{in call}}
 }
+
+namespace GH57431 {
+class B {
+  virtual int constexpr f() = 0;
+};
+
+class D : B {
+  virtual int constexpr f() = default; // expected-error {{only special member functions and comparison operators may be defaulted}}
+};
+}