Corrections for clear issues identified by g++-11 (or while trying g++11). Plus the addition of const into abstraction and revert of swap disable for forward trees.
Pipeline #137374 passed with warnings
Pipeline passed with warnings for 20a3a7d0 on tidy-fixes-merge 3 years ago
Pipeline #137595 passed with warnings
Pipeline passed with warnings for 20a3a7d0 on master 3 years ago
merged