It's funny seeing "common law" referred as a US thing when it's literally been in use in the UK for centuries before the US was a thing, and that's where the US inherited it from.
And precedent has it's place in civil law countries too, mostly around clarifying existing legislation in case of ambiguity, but it isn't an automatic ironclad thing.
An interesting quirk of English law is that murder is a common law offence. There is no Act of Parliament proscribing it; it's just something that everybody has always accepted is a crime.
And precedent has it's place in civil law countries too, mostly around clarifying existing legislation in case of ambiguity, but it isn't an automatic ironclad thing.