PR Summary

This fixes a bug in ForEach-Object -Parallel where a using variable in a nested ForEach-Object -Parallel throws an error even when the variable is defined in the correct scope (Issue #11817).

PR Context

This error was occurring because, when ForEach-Object -Parallel was assembling the user variable map, it was searching all nested scriptblocks within the ForEach scriptblock, with the result of finding nested using variables where the variable had not yet been defined. Since the nested scriptblock using variable had not been defined in the current scope, a mapping error was thrown.

Fix is to change the using variable map function to not search nested scriptblocks in the ForEach -Parallel case. This way foreach -parallel using variable mapping is always performed only for the current scope.

Many thanks to @mklement0 for pointing out the fix.

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