During bootstrapping, the script's name is not necessarily set.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 7b77d893f15451738d6ecada03a7eafa7ca600de..653ff2ef79d4593b3de0e1da7bdbc3e9708cdc93 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1400,17 +1400,19 @@ void Isolate::DoThrow(Object* exception, MessageLocation* location) {
       // to the console for easier debugging.
       int line_number = GetScriptLineNumberSafe(location->script(),
                                                 location->start_pos());
-      if (exception->IsString()) {
+      if (exception->IsString() && location->script()->name()->IsString()) {
         OS::PrintError(
             "Extension or internal compilation error: %s in %s at line %d.\n",
             *String::cast(exception)->ToCString(),
             *String::cast(location->script()->name())->ToCString(),
             line_number + 1);
-      } else {
+      } else if (location->script()->name()->IsString()) {
         OS::PrintError(
             "Extension or internal compilation error in %s at line %d.\n",
             *String::cast(location->script()->name())->ToCString(),
             line_number + 1);
+      } else {
+        OS::PrintError("Extension or internal compilation error.\n");
       }
     }
   }