[erlang-questions] Bit Syntax and compiler Erlang/OTP R21.1

Valentin Micic v@REDACTED
Tue Aug 20 14:26:01 CEST 2019

Hi all,

Recently I’ve made a silly mistake. I wrote:

case Payload of
   <<_:4/binary-unit:8, _:255, _:7/binary-unit:8, 0:16>>   -> Payload;
   _                                                       -> throw( drop )

Instead of:

case Payload of
   <<_:4/binary-unit:8, 255:8, _:7/binary-unit:8, 0:16>>   -> Payload;
   _                                                       -> throw( drop )

Considering that overall pattern (which erroneously references 255 bits long field, instead of an octet with a value of 255 ) is not aligned to 8-bit boundary, is it unreasonable to expect the compiler to report this as a potential problem, or  at least generate a warning (support for bit-fields notwithstanding).

What am I missing here?


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