Make MCSE for constant arrays always return a NaN

[sethaxen]

Fixes #122

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.70%. Comparing base (877214d) to head (b73fae2).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #128      +/-   ##
==========================================
+ Coverage   96.68%   96.70%   +0.01%     
==========================================
  Files          10       10              
  Lines         875      880       +5     
==========================================
+ Hits          846      851       +5     
  Misses         29       29              

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[coveralls]

Pull Request Test Coverage Report for Build 11894022521

Details

• 5 of 5 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 96.705%

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Totals
Change from base Build 11882481146:	0.02%
Covered Lines:	851
Relevant Lines:	880

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💛 - Coveralls

[sethaxen]

#129 should be merged first