Steps to reproduce

Run ForeachArrayMergeSniff against file that contains inline control structure.

foreach ([] as $item)
// inline foreach
    $a = array_merge([], []);

foreach ([] as $item)
// array_merge after inline foreach
$a = array_merge([], []);

Expected result

Sniff detects nothing. There is no way to detect function scope without {}.

Actual result

An error occurred during processing; checking has been aborted. The error message was: Undefined index: scope_opener in ...