small corrections in clamp implementation

4 jobs for issue/clamp_operations in 22 minutes and 52 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #6969
debian:10 clang-6-libcpp-17

00:20:56

passed #6968
debian:10 gcc-8-17

00:16:20

passed #6970
debian:9 gcc-6-14

00:13:21

passed #6971
ubuntu:18.04 clang-6-17

00:19:00