The practical test concerns the listener’s prior position: imagined combination produces ifrād; belief in the opposite produces qalb; uncertainty over which alternative applies produces taʿyīn.
The framework is not limited to one example of a subject restricted to an attribute. It can be applied to attribute-to-subject restriction as well, subject to the logical possibilities of the alternatives.
TypeListener’s starting pointCorrection
IfrādBoth writer and poetDeny conjunction
QalbPoet, not writerReverse belief
TaʿyīnWriter or poet? undecidedDetermine the correct alternative