In tweets not worth embedding here, or anywhere, Trump said on Thursday that he "never called John a loser." Amid the same series of tweets, Trump also disputed an Atlantic report from this week in which "people with firsthand knowledge" recalled a 2018 incident in which Trump is said to have referred to Americans who died in war as both "losers" and "suckers."
As for the McCain-centered lie, a mere cursory Googling—as many have since pointed out—will result in footage of Trump quite literally calling McCain a "loser." During a 2015 campaign event, Trump referred to McCain as a "loser" while also stating that he was "not a war hero" due to being captured.
"He lost. He let us down. He lost," Trump said at the time. "So I never liked him as much after that because I don't like losers. He's not a war hero. He's a war hero because he was captured. I like people that weren't captured, okay? I hate to tell you."
That same year, Trump—as can still be seen on his Twitter account—shared an article from whatever FITSNews is titled "Donald Trump: John McCain Is 'A Loser.'" And as CNN pointed out in their extensive fact check of Trump's many McCain-centered comments, has also—on many occasions—erroneously claimed to have done more for veterans than McCain.
Anyway, check this out: