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    Working with cryptic error messages from ReasonML when writing custom Decco decoders.


    Decco is a language extension that automatically generates JSON encoders and decoders from type signatures. When adding adding custom Decoders, the error messages that the compiler produces can be quite confusing. This lesson shows the viewer how to use explicit type signatures to narrow down where an error might be coming from in custom codec code. This same pattern can be applied whenever confusing error messages come from code that is written without explicit type signatures.