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What you were trying to do (and why)

Install a formula from a tap.

What happened (include command output)

Received an error message.

Error: undefined method `build_head?' for ["hogan"]:Array
Please report this bug:
  https://docs.brew.sh/Troubleshooting
/usr/local/Homebrew/Library/Homebrew/extend/ARGV.rb:188:in `collect_build_flags'
/usr/local/Homebrew/Library/Homebrew/formula_installer.rb:82:in `prevent_build_flags'
/usr/local/Homebrew/Library/Homebrew/cmd/install.rb:134:in `install'
/usr/local/Homebrew/Library/Homebrew/brew.rb:102:in `'
  

What you expected to happen

Formula was installed

Step-by-step reproduction instructions (by running brew commands)

brew tap cvent/taps
brew install hogan

I believe the root of this problem is this PR: 18630c7#diff-4057e3104180677e293e1facd6513179L207

Note that on line 198 (original file), the function build_head is removed. A reference to this is removed in line 207 (original). However, if you look at the current state of the file:

you can see there's another ref to this function still in the current version. I suspect that call just needs to get removed, but I'm not confident enough to go ahead and submit a PR.

brew-doctor.txt
brew-config.txt