diff --git a/source/dub/generators/cmake.d b/source/dub/generators/cmake.d
index d00d067..aab50f5 100644
--- a/source/dub/generators/cmake.d
+++ b/source/dub/generators/cmake.d
@@ -101,7 +101,7 @@
                 script.put(
                     `set_target_properties(%s PROPERTIES TEXT_INCLUDE_DIRECTORIES "%s")`.format(
                         name,
-                        info.buildSettings.stringImportPaths.join(";")
+                        info.buildSettings.stringImportPaths.dup.join(";")
                     ) ~ "\n"
                 );
             }