Sorry, I don't consider that thread to be a reputable source.It's mentioned in the All the Little Things thread, although it talks about QuickTime and Quicklook specifically; not iTunes.
SRLMJ23, does the file play in QuickTime Player?
Sorry, I don't consider that thread to be a reputable source.
I did search for "FLAC" on the Apple support site and it looks like FLAC playback is support on iPhone 7, iPhone 7 Plus, iPhone 8, iPhone 8 Plus, iPhone X, Apple TV 4K.
There is no indication from the Apple support pages that FLAC is supported by QuickTime or iTunes.
Sorry, I don't consider that thread to be a reputable source.
I did search for "FLAC" on the Apple support site and it looks like FLAC playback is support on iPhone 7, iPhone 7 Plus, iPhone 8, iPhone 8 Plus, iPhone X, Apple TV 4K.
There is no indication from the Apple support pages that FLAC is supported by QuickTime or iTunes.
Another Internet search led me to an article that indicates that FLAC is supported by Quick Look in High Sierra. It appears that FLAC audio files can be previewed in Finder.

Also I hate it when people bring up the 'but you can't tell the difference' argument. Well I can definitely hear more clarity in the detail of a few albums I own in 24-bit 96KHz FLAC compared to their 320kbps VBR versions on Spotify. And I've asked family to blind test me just to see.
Have also just discovered that Quicktime will process FLAC but iTunes still chokes it out. Does anyone know if there's plans in the pipeline for this to become an iTunes feature?
Also I hate it when people bring up the 'but you can't tell the difference' argument. Well I can definitely hear more clarity in the detail of a few albums I own in 24-bit 96KHz FLAC compared to their 320kbps VBR versions on Spotify. And I've asked family to blind test me just to see.