Initial coalesce operator implementation
Added test
Ensure not evaluated twice
simplify the condition
fix the REPARSE_DATA_BUFFER struct def
added a comment
Replace IS_OP?_TMP_FREE() with more clear (OP?_TYPE == IS_TMP_VAR)
Make error paths to be UNEXPECTED
Optimized unset()
Specialization (only IS_VAR ad IS_CV operands may be references)
Avoid useless reference counting
Remove php_varname_check

This is a leftover from PHP < 5.4.

Also removed the php_create_empty_class declaration, which no longer
exists.
Fix list() destructuring to special variables
Fixed typo
Remove static allocator

We didn't even compile this file anymore
Remove zend_dynamic_array

This was introduced back in 2000 to test a new hashtable
implementation and is no longer used.
Fix tests/serialize/bug64146.phpt

The var hash now retains a reference to its elements, to ensure
that addresses are not reused.

Furthermore the var hash now only stores objects and references
and directly uses their pointer as key, thus making serialization
about two times faster.
Test some additional cases for constexpr evaluation
Test error conditions for ct class const refs

And fix a bug found while doing so...
Test a few more error conditions in the compiler