fix Issue 12593 - AA cannot have struct as key
Do not mark mutable parameters as STCin for internal library calls
Merge pull request #3481 from ibuclaw/stcin

Do not mark mutable parameters as STCin for internal library calls
Merge pull request #3476 from 9rnsr/fix12593

[REG2.065] Issue 12593 - AA cannot have struct as key
fix Issue 12606 - Mismatch of known array length during dynamic => static array assignment should emit better diagnostics

Recognize slice expression on initializer and rhs of assignment