Catch Bad Validation Tags at Compile Time with checkerlint

Struct tags are just strings — a typo'd checker name, a wrong-typed field, or a renamed cross-field target all compile fine and fail silently at runtime. checkerlint catches all three before you ship. Struct tags are string literals. The Go compiler checks that your struct compiles — it has no idea what checkers:"eq-field:Passwrd" means, so a typo in a field name, a checker applied to a field of the wrong type, or a renamed field that a cross-field rule still points at all compile fine. They fail later, at runtime, sometimes silently, sometimes as a panic in the middle of handling a request. type Registration struct { Password string `checkers:"trim required"` ConfirmPassword string `checkers:"required eq-field:Passwrd"` // typo: no such field Age int `checkers:"email"` // email is string-only } Nothing here trips go build , go vet , or a normal linter — they all treat checkers:"..." as an opaque string. The first bug only surfaces the moment someone submits a registration form and eq-field can't find a field called Passwrd . The second is worse: email assumes a string under the hood, so calling it on an int field panics at validation time instead of returning a normal error. checkerlint is a go/analysis -based static analyzer, shipped as its own module in the Checker repo, that reads these tags at build/lint time and catches exactly this class of bug before it ships: ./registration.go:3:2: checkerlint: eq-field references field "Passwrd", which doesn't exist on this struct ./registration.go:4:2: checkerlint: email requires a string, but the field's type is int What it actually checks Three things, all specific to how checkers / validate tags can go wrong: Unknown checker names. Every token in the tag has to be a registered checker, normalizer, field-relative checker, omitempty , or a name your own code registered via RegisterMaker / RegisterFieldMaker with a string literal. Typo requird instead of required and checkerlint flags it — nothing else in your toolchain w