Confirmed in ZF-9313, there will be no further workarounds/fixes for php 5.2.0 issues, as was raised in ZF-1743, e.g.,
$identifier1->$identifier2['array'] = $value;
This will be a recurring maintenance issue until we raise Piwik's PHP requirement and/or ZF moves to php 5.3.x as the minimum supported issue.
Use the following to locate the problematic code in source files:
grep -R -E '\->[a-zA-Z0-9_]+\->[a-zA-Z0-9_]+\[' * | fgrep -v .svn
As of r1881, these files require the tmp variable workaround: