Make SingleImpl warning quieter
Make SingleImpl warning quieter

Summary: Print a single warning to re-run with tracing.

Reviewed By: ssj933

Differential Revision: D27756716

fbshipit-source-id: fd8ac80be762fbe54a0ff08f6d9ce094e1861aa2

facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex