diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -4571,8 +4571,9 @@
 
   // Find expected alignment, and the actual alignment of the passed object.
   // getTypeAlignInChars requires complete types
-  if (ParamTy->isIncompleteType() || ArgTy->isIncompleteType() ||
-      ParamTy->isUndeducedType() || ArgTy->isUndeducedType())
+  if (ArgTy.isNull() || ParamTy->isIncompleteType() ||
+      ArgTy->isIncompleteType() || ParamTy->isUndeducedType() ||
+      ArgTy->isUndeducedType())
     return;
 
   CharUnits ParamAlign = Context.getTypeAlignInChars(ParamTy);
diff --git a/clang/test/SemaCXX/recovery-expr-type.cpp b/clang/test/SemaCXX/recovery-expr-type.cpp
--- a/clang/test/SemaCXX/recovery-expr-type.cpp
+++ b/clang/test/SemaCXX/recovery-expr-type.cpp
@@ -136,3 +136,10 @@
   bar(S(123)); // expected-error {{no matching conversion}}
 }
 } // namespace test11
+
+namespace test12 {
+// Verify we do not crash.
+void fun(int *foo = no_such_function()); // expected-error {{undeclared identifier}}
+void baz() { fun(); }
+} // namespace test12
+