minor concepts fixes #901

Job	Run time
Build Doxygen Docs	54s
Sanitize - tsan	4m 23s
Test RPP as package - ubuntu-latest	1m 16s
Sanitize - asan	4m 43s
tests ci-ubuntu-gcc Release	7m 22s
Sanitize - lsan	3m 46s
tests ci-ubuntu-gcc Debug	7m 1s
Sanitize - ubsan	2m 53s
benchmarks ci-ubuntu-gcc Release	2m 18s
benchmarks ci-ubuntu-gcc Debug	2m 35s
tests ci-ubuntu-clang Release	9m 3s
tests ci-ubuntu-clang Debug	7m 10s
benchmarks ci-ubuntu-clang Release	3m 54s
benchmarks ci-ubuntu-clang Debug	3m 40s
tests ci-windows Release	4m 58s
tests ci-windows Debug	3m 45s
benchmarks ci-windows Release	2m 29s
benchmarks ci-windows Debug	2m 7s
tests ci-macos Release	6m 32s
tests ci-macos Debug	3m 40s
benchmarks ci-macos Release	3m 9s
benchmarks ci-macos Debug	1m 47s
	1h 29m 25s

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