IntelliJ products instructions

This should work for Fira Code 1.102 and IntelliJ products v. 15 and later (IDEA, PhpStorm, PyCharm, RubyMine, WebStorm, AppCode, CLion, DataGrip):

• Create idea.properties file (see how and where)
• Add this:

editor.enable.optional.ligatures=true

• Restart your IDE

NOTE: IDEA support of ligatures is considered experimental. E.g. scroll performance may be very slow. It has been reported here

NOTE: There’s an issue on OS X when Fira Code Light is used instead of Regular weigth by default (discussion). To work around that, do not install Light weight at all. (this is fixed in latest 16 EAP)