Both go and OCaml use LR parser generators, precisely because they make it easy to give excellent error messages.

Basically the key insight is that you can use the parsing automaton state to classify syntax errors, which makes it as easy as falling off a log to produce good messages. The paper originating this technique is Clinton Jeffery's TOPLAS 2003 paper “Generating LR Syntax Error Messages from Examples.” This is what go uses, and OCaml uses a more advanced version of this technique introduced by Francois Pottier in his CC 2016 paper "Reachability and Error Diagnosis in LR(1) Parsers".