@TomasVotruba @staabm this is Node flag true or false example that I meant. For this PR, is to detect that variable may be a global variable.

$variable = 'value';

function foo()
{
       global $variable;

       echo $variable;
}

The detection is by create new GlobalVariableNodeVariableVisitor by loop the StmtsAwareInterface stmts if there is Global_ stmt, then check on next stmt on loop.

This implementation is currently for Global detection on VariableAnalyzer

https://github.com/rectorphp/rector-src/pull/3816/files#diff-8b66a0350e903758d4d9cc4e625a0383881d1830a878ed3d37d3cbec801bce1c

if this is accepted, we can create detection for static one so no more findFirstPrevious() for this detection.