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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Unexpected parsing errors with array literals as array-index expressions in method calls","articleBody":"Using a literal array of indices as an index expression breaks in method calls.\r\n\r\nIt looks like the `,` that's part of the array literal is misconstrued as a method-argument separator.\r\n\r\nSteps to reproduce\r\n------------------\r\n\r\n```powershell\r\n[string]::join(' ', (0, 1, 2)[0, 1])\r\n```\r\n\r\nExpected behavior\r\n-----------------\r\n\r\n```none\r\n0 1\r\n```\r\n\r\nActual behavior\r\n---------------\r\n\r\n```none\r\nAt line:1 char:32\r\n+ [string]::join(' ', (0, 1, 2)[0, 1])\r\n+                                ~\r\nMissing ']' after array index expression.\r\nAt line:1 char:35\r\n+ [string]::join(' ', (0, 1, 2)[0, 1])\r\n+                                   ~\r\nMissing ')' in method call.\r\nAt line:1 char:35\r\n+ [string]::join(' ', (0, 1, 2)[0, 1])\r\n+                                   ~\r\nUnexpected token ']' in expression or statement.\r\nAt line:1 char:36\r\n+ [string]::join(' ', (0, 1, 2)[0, 1])\r\n+                                    ~\r\nUnexpected token ')' in expression or statement.\r\n+ CategoryInfo          : ParserError: (:) [], ParentContainsErrorRecordException\r\n+ FullyQualifiedErrorId : MissingEndSquareBracket\r\n```\r\n\r\nTo make the command work, you currently have to enclose either the entire expression in `(...)`:\r\n\r\n```powershell\r\n[string]::join(' ', ((0, 1, 2)[0, 1]))  # OK\r\n```\r\nor just the array inside `[...]`:\r\n\r\n```powershell\r\n[string]::join(' ', (0, 1, 2)[(0, 1)]) # OK\r\n```\r\n\r\nor use a variable:\r\n\r\n```powershell\r\n$a = 0, 1; [string]::join(' ', (0, 1, 2)[$a]) # OK\r\n```\r\n\r\nAlso, a _single_ index works as expected:\r\n\r\n```powershell\r\n[string]::join(' ', (0, 1, 2)[0])  # OK\r\n```\r\n\r\nUsing the `-join` _operator_ makes the problem go away:\r\n\r\n```powershell\r\n(0, 1, 2)[0, 1] -join ' '  # OK\r\n```\r\n\r\nIn short: avoiding a `,` in the index expression is needed to make the problem go away; such a `,` appears to be mistaken for a method-argument separator.\r\n\r\nEnvironment data\r\n----------------\r\n\r\n```powershell\r\nPowerShell Core v6.1.0-preview.2 on macOS 10.13.4\r\nPowerShell Core v6.1.0-preview.2 on Ubuntu 16.04.4 LTS\r\nPowerShell Core v6.1.0-preview.2 on Microsoft Windows 10 Pro (64-bit; Version 1709, OS Build: 16299.371)\r\nWindows PowerShell v5.1.17134.48 on Microsoft Windows 10 Pro (64-bit; Version 1709, OS Build: 16299.371)\r\n```\r\n","author":{"url":"https://github.com/mklement0","@type":"Person","name":"mklement0"},"datePublished":"2018-06-05T18:52:19.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/7004/PowerShell/issues/7004"}