Methods, computer systems, computer-storage media, and graphical user interfaces are provided for facilitating data type detection, according to embodiments of the present invention. In one embodiment, existing code is searched to identify a set of functions related to a target data type. Such functions can be executed using positive example values and negative example values. For each executed function, a logical explanation is generated that represents a distinction in execution of the positive example values from the negative example values. The executed functions can then be ranked based on the extent to which the corresponding logical explanations distinguish execution of the positive example values from the negative example values. A function suggestion corresponding with at least a highest ranked function can then be provided, for example to a user, to indicate a function for use in detecting the target data type.