CollectFileDescriptorSet builds a file descriptor set associated with the file where the input message is declared.

NewDb creates a new `pb.Db` with an empty type name to file description map.

CheckedPrimitives map from proto field descriptor type to expr.Type.

CheckedWellKnowns map from qualified proto type name to expr.Type for well-known proto types.

DefaultDb used at evaluation time or unless overridden at check time.

Db maps from file / message / enum name to file description.

EnumDescription maps a qualified enum name to its numeric value.

FieldDescription holds metadata related to fields declared within a type.

FileDescription holds a map of all types and enums declared within a .proto file.

TypeDescription is a collection of type metadata relevant to expression checking and evaluation.