fix unsilenceable warnings on GCC 9#41

cuviper merged 1 commit intorust-lang:rustc/9.0-2019-12-19rust-lang/llvm-project:rustc/9.0-2019-12-19from

contrun:fix-gcc-9-warningcontrun/llvm-project:fix-gcc-9-warningCopy head branch name to clipboard