Changeset [9b423ac0b73483c4a812d7376f818e831f909120] by Xavier Noria

let this regexp be stricter

The purpose of this regexp is to detect strings that
are valid identifiers to be used as method names.
The anchor $ allows a trailing newline, and both ^
and $ may be bypassed because Ruby regexps are
multiline always. The anchors \A and \z are the
proper ones to ensure string boundaries.
https://github.com/rails/rails/commit/9b423ac0b73483c4a812d7376f818...