unexpected error(Solved)

Question

Ok, I can't understand why this admittedly unnecessarily complicated one liner cannot be used in a for loop.
It works when arguments are passed directly but raises error in the for loop.
Is this a limitation of the walrus operator or the lambda scope getting messed up?
Any ideas?
I like to experiment a bit and push the code to see what it takes to break it. It breaks here...

(Solved, thanks to insight provided by Jay Matthews ' feedback.)

https://code.sololearn.com/cve349Ch6v5k/?ref=app

https://code.sololearn.com/cPp7I7Eh68eO/?ref=app

Answer 1

Jay Matthews
you're right!
so it's not about the for range, but about arguments fed to it.
it fails on mtx(0) and mtx(1).
what's going on?

Answer 2

Jay Matthews
agreed. Maybe the lambda was wrongly written?
The commented out functions below that all works down to 0.
Nesting lambdas is tricky.

Answer 3

Jay Matthews
Thanks to your insight, I decided to take out the inner nested lambda and put it in the outer lambda parameter, so the nesting weirdness go away.