@Gabor, have you ever managed to compile R/igraph with Address Sanitizer on macOS? Generally, one needs -fsanitize=address -fno-omit-frame-pointer when compiling/linking and additionally the ASan libraries would need to be loaded early, which could be achieved by starting R as
DYLD_INSERT_LIBRARIES=/path/to/asan/lib R
However, the devtools package seems to launch additional R processes which don’t have this library loaded.
For now I am just looking for an easier way to understand which bugs reported for R/igraph are actually bugs in the C core. There’s e.g. this one which involved a specific seed for R’s RNG.