presto-main/src/main/java/io/prestosql/operator/annotations/CastImplementationDependency.java/CastImplementationDependency/getResolvedFunction
class CastImplementationDependency:    @Override
    protected ResolvedFunction getResolvedFunction(BoundVariables boundVariables, Metadata metadata)
    {
        return metadata.getCoercion(
                metadata.getType(applyBoundVariables(fromType, boundVariables)),
                metadata.getType(applyBoundVariables(toType, boundVariables)));
    }