diff --git a/lld/MachO/Writer.cpp b/lld/MachO/Writer.cpp
--- a/lld/MachO/Writer.cpp
+++ b/lld/MachO/Writer.cpp
@@ -748,7 +748,7 @@
   for (const InputFile *file : inputFiles) {
     if (isa<ObjFile>(file))
       for (Symbol *sym : file->symbols)
-        if (auto *d = dyn_cast<Defined>(sym))
+        if (auto *d = dyn_cast_or_null<Defined>(sym))
           addSym(*d);
   }
 
diff --git a/lld/test/MachO/order-file.s b/lld/test/MachO/order-file.s
--- a/lld/test/MachO/order-file.s
+++ b/lld/test/MachO/order-file.s
@@ -172,3 +172,7 @@
 _main:
   callq "-[Foo doFoo:andBar:]"
   ret
+
+.section  __DWARF,__debug_aranges,regular,debug
+ltmp1:
+  .byte 0