diff --git a/lld/MachO/SyntheticSections.cpp b/lld/MachO/SyntheticSections.cpp
--- a/lld/MachO/SyntheticSections.cpp
+++ b/lld/MachO/SyntheticSections.cpp
@@ -585,8 +585,10 @@
 }
 
 static bool shouldExportSymbol(const Defined *defined) {
-  if (defined->privateExtern)
+  if (defined->privateExtern) {
+    assert(defined->isExternal() && "invalid input file");
     return false;
+  }
   // TODO: Is this a performance bottleneck? If a build has mostly
   // global symbols in the input but uses -exported_symbols to filter
   // out most of them, then it would be better to set the value of
@@ -844,7 +846,6 @@
       if (!shouldExportSymbol(defined)) {
         // Private external -- dylib scoped symbol.
         // Promote to non-external at link time.
-        assert(defined->isExternal() && "invalid input file");
         scope = N_PEXT;
       } else if (defined->isExternal()) {
         // Normal global symbol.
diff --git a/lld/test/MachO/export-options.s b/lld/test/MachO/export-options.s
--- a/lld/test/MachO/export-options.s
+++ b/lld/test/MachO/export-options.s
@@ -38,6 +38,8 @@
 .private_extern _private_extern
 _private_extern:
   retq
+_private:
+  retq
 
 ## Check that the export trie is unaltered
 # RUN: %lld -dylib %t/default.o -o %t/default