chocolatey/chocolatey — pull request #421 by bill-long (2014-02-21 01:22:41+00:00)
Title: Get-BinRoot defaulted to "C:\" instead of "C:\tools"

Line 15 set $binRoot to C:\tools, but did not set $env:ChocolateyBinRoot. Thus, the expression on line 23 evaluates $false (because $env:ChocolateyBinRoot is still $null), so line 25 overwrites $binRoot with just "C:\".