[layer8]

Regarding the second one, a formatter shouldn’t be changing the AST. At most inserting parentheses/braces/semicolons for clarity, which doesn’t change the AST structurally (or, depending on one‘s definition of “AST”, doesn’t change it at all).

[o11c]

Perhaps, but it is absolutely relevant. Most of the horrible formatting results are due to the formatter trying really hard when the user really should introduce a variable.

[layer8]

True, formatters can only do so much. The purpose formatters is not to guarantee readable code, but to guarantee uniform code. Use of a formatter doesn’t relieve a programmer from taking care that the code is readable. But it ensures that everyone is using the same formatting conventions.