^{Supersedes #4472}

In said cmdlets, -Path is declared as [string[]], so these cmdlets are capable of accepting multiple files, if passed an array of paths; ditto for -LiteralPath.

Passing a (single) wildcard expression that itself resolves to multiple files unexpectedly breaks, however.

The culprit may be that ReportMultipleFilesNotSupported() is called, whose purpose is to prevent resolution to multiple paths, but whose use is not appropriate in this case.

Note: Potentially, additional cmdlets are affected - you can find the list of candidates (some of which are definitely not affected) as follows:

gcm -parametername path | ? { $_.parametersets.parameters.parametertype -eq [string[]] }

Steps to reproduce

"one,two`nuno,due" > file1.csv
"one,two`nun,deux" > file2.csv

Import-Csv -LiteralPath file1.csv, file2.csv
' vs. '
Import-Csv -Path file[12].csv

Expected behavior

one two 
--- --- 
uno due 
un  deux
 vs. 
uno due 
un  deux

Actual behavior

one two 
--- --- 
uno due 
un  deux
 vs. 
Import-Csv : Cannot perform operation because the path resolved to more than one file. This command cannot operate on multiple files.
At /foo.ps1:21 char:1
+ Import-Csv -Path file[12].csv
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : InvalidArgument: (:) [Import-Csv], PSInvalidOperationException
+ FullyQualifiedErrorId : ReadWriteMultipleFilesNotSupported,Microsoft.PowerShell.Commands.ImportCsvCommand

Environment data

PowerShell Core v6.0.2 on macOS 10.13.3
PowerShell Core v6.0.2 on Ubuntu 16.04.3 LTS
PowerShell Core v6.0.2 on Microsoft Windows 10 Pro (64-bit; v10.0.15063)
Windows PowerShell v5.1.15063.674 on Microsoft Windows 10 Pro (64-bit; v10.0.15063)