Fwd: A: a new bug to old plain C

[ANDREY TARASEVICH]

There's no bug in what you posted. Conversition from 'T **' to 'const T *const *' has never been allowed as an implicit conversion in standard C (as opposed to C++, which allows this). A compliant C compiler should issue a diagnostic for this code since this is a constraint violation, which is exactly what your compiler did.
 
If I'm not mistaken, C23 is/was supposed to bring C on sync with C++ wrt this matter.
 
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Best regards
Andrey Tarasevich