The trick is to ban even the correct but (to a human) ambiguous patterns. In this case, I wouldn't let you do assignment on the same line as the conditional.
With an `if` it's probably superfluous and therefore bannable without cost, but sometimes it can make a `while` loop so much more concise - since the alternative would be to write the same code before the loop and at the bottom of the loop. It is the cost of inexpressive languages.
In many people’s head-parser, the first one looks like an equality check (but is in fact assignment). The parens try to clue people into “this is an assignment expression!” I think, but personally I wouldn’t allow an assignment expression in an if statement even with parens.
While you have a point, I don't think the exception should disprove the rule. Even if a few specific style patterns can't be automated, the bulk can be and it's probably better to have them enforced at the pre-compile stage.