Another Wikipedia mistake. They say Cheech Marin is of Iranian descent:
"Cheech is, by his own admission, ethnically Iranian. In an article published July 27th, 2006 in Canada's The Province, he plainly states that despite being typecast as a chicano he is in fact Iranian."
Unfortunately, ace Wikipedia editor TheKyleD, the guy who insists Cheech is not Chicano, doesn't recognize that comedian Cheech was making a joke when claiming to be Iranian. At least two easily-findable online articles make it clear that his parents were Mexican.
Wikipedia: your well-read friend who can tell you about all the stuff he's read, but you can't really be sure if what he's read is true.