> (Main annoying thing: a lot of compilers, even popular ones such as clang and gcc, don't actually seem to know what the precedence rules actually are, and generate warnings asking you to clarify. Presumably the authors didn't realise that C has an ISO standard, that can be consulted to answer this question? Very surprising.)

The compilers do know what the precedence rules are, but they know that programmers don't routinely consult the ISO standard, so they emit those warnings to reduce the chance of error. Compilers are tools that are designed to help programmers avoid bugs. If they don't help programmers, they aren't doing their job.