Steps to Reproduce

attached xlsx sample

Current Result

In 5.8.0, the formula =SUMPRODUCT(–({true; true; false})  (not an actual array, just showing the result of the LEN function in the example) has the result value "1" 

Expected Result

Expected value is "2" 

Debug Information

org.zkoss.poi.ss.formula.functions.OverridableFunction.evaluate(ValueEval[], int, int, boolean)

calls 

org.zkoss.poi.ss.formula.functions.Fixed1ArgFunction.evaluate(ValueEval[], int, int)

which calls

org.zkoss.poi.ss.formula.functions.Fixed1ArgFunction.evaluate(ValueEval[], int, int, boolean)

with the isArrayValue boolean set to false

This causes the resulting arg passed to the outer formula to be a  org.zkoss.poi.ss.formula.eval.NumberEval instead of the expected org.zkoss.poi.ss.formula.eval.ArrayEval

Since sumproduct should apply the double minus sign conversion from boolean to int (1 or 0), the sum applied to the array should return an integer equal to the number of "true" values in the array

Workaround

N/A