I’m sure everyone is familiar with this error and the issue tracker is likely full of reports since the error instructs you to open an issue.
Could I suggest that Brew tests for /private/tmp having the correct permissions as part of it’s “doctor” option, and if it finds that either offer to fix it or prompt the user to run “sudo chmod +t /private/tmp”?
Googling the issue is problematic because of the sheer number of duplicate github issues that are all closed and varying responses (“Run all the checks”, “update”, “run disk utility”, “chmod the dir”).
If there’s concern about asking users to run the “chmod” command, there is a command-line option for the official OS-X Repair Permissions tool: “diskutil verifyPermissions /” to check and “diskutil repairPermissions /” to fix.
Just a suggestion if any developers hang out here, didn’t want to clutter the issue tracker.