Syntax checker does not work with workspaces in PowerShell

[fleetingbytes]

• rust.vim version: current

Steps to reproduce:

• have MS PowerShell as the shell in which vim runs (e.g. $Env:ComSpec=C:\WINDOWS\SysWOW64\WindowsPowerShell\v1.0\powershell.exe)

" in .vimrc
" Set Powershell as the shell of choice
let &shell = has('win32') ? 'powershell' : 'pwsh'
let &shellcmdflag = '-NoLogo -NoProfile -ExecutionPolicy RemoteSigned -Command [Console]::InputEncoding=[Console]::OutputEncoding=[System.Text.Encoding]::UTF8;'
let &shellredir = '2>&1 | Out-File -Encoding UTF8 %s; exit $LastExitCode'
let &shellpipe = '2>&1 | Out-File -Encoding UTF8 %s; exit $LastExitCode'
set shellquote=\" shellxquote=
set noshelltemp

• have a rust project with a workspace
• edit a file inside the workspace (e.g. a .rs file inside the embedded library) so that syntax-checkers/rust/cargo.vim would have to enter this fork of the cargo.vim script
• save the .rs source file so that rust syntax-checker runs

Expected vs. actual behavior:

Actual:

• This happens because PowerShell does not chain commands with && like other shells, so it errors out at (cd <path> && cargo check)

Expected:

• Chain commands with ; if Powershell is used.
• I corrected it for myself like this (replaced && with ) ; () in here:

    if rust#GetConfigVar('rust_cargo_avoid_whole_workspace', 1)
        if l:root_cargo_toml !=# l:nearest_cargo_toml
            let makeprg = "cd " . fnamemodify(l:nearest_cargo_toml, ":p:h")
                        \ . ") ; (" . makeprg
        endif
    else
        let makeprg = "cd " . fnamemodify(l:root_cargo_toml, ":p:h")
                    \ . ") ; (" . makeprg
    endif

• a mere ; is not enough because then you'd end one powershell command without closing the parenthesis.
• The script needs some logic to do this type of command chaining only when PowerShell is used as shell.