fixup! don't overwrite variable type

Author: Michael137

lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

@@ -3423,7 +3423,10 @@ VariableSP SymbolFileDWARF::ParseVariableDIE(const SymbolContext &sc,
       mangled = form_value.AsCString();
       break;
     case DW_AT_type:
-      type_die_form = form_value;
+      // DW_AT_type on declaration may be less accurate than
+      // that of definition, so don't overwrite it.
+      if (!type_die_form.IsValid())
+        type_die_form = form_value;
       break;
     case DW_AT_external:
       is_external = form_value.Boolean();