ForeEach-Object -Parallel using variable processing walks the script block AST to determine if the using variable was defined in the current scope, and does this by tracking the number of 'ForEach-Object -Parallel' commands in the call chain.
However, the provided script block is different, depending on whether it is passed in as a variable or via parameter binding.
$myScript = '"Hello!"'
1 | ForEach-Object -Parallel ([scriptblock]::Create($myScript))
# Script block Ast does not contain the 'ForEach-Object' command in the call chain
1 | ForEach-Object -Parallel { "Hello!" }
# Script block Ast does contain the 'ForEach-Object' command in the call chain
This change takes into account the two forms of script blocks
Ryne Andal