diff --git a/stdlib/public/Observation/Sources/Observation/CMakeLists.txt b/stdlib/public/Observation/Sources/Observation/CMakeLists.txt
index 1b5d5eb255838..dc17b06f16f74 100644
--- a/stdlib/public/Observation/Sources/Observation/CMakeLists.txt
+++ b/stdlib/public/Observation/Sources/Observation/CMakeLists.txt
@@ -28,6 +28,7 @@ add_swift_target_library(swiftObservation ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS
   SWIFT_COMPILE_FLAGS
     ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
     "-enable-experimental-feature" "Macros"
+    -Xfrontend -disable-implicit-string-processing-module-import
 
   C_COMPILE_FLAGS
     ${swift_runtime_library_compile_flags}