pointless comparison hint is frequently very off base

[lolbinarycat]

code (playground):

def is_some(n):
    n is not None

here, the user is trying to do an implicit return, but python does not have implicit returns. the hint given is this:

B015: Pointless comparison. Did you mean to assign a value? Otherwise, prepend `assert` or remove it.

the chance of someone meaning to write = and instead writing is not is approximately zero. if a pointless comparison appears at the end of a function, it should suggest returning it instead of suggesting assert, and the assignment suggestion should only appear if the operator contains =.

[MichaReiser]

Makes sense to me. We can probably improve the message over all.

[AlexWaygood]

the chance of someone meaning to write = and instead writing is not is approximately zero.

FWIW, I don't think that's the assumption the rule is making when it says "Did you mean to assign a value?". Instead, I think the rule is assuming that the user meant to write something like

def is_some(n):
    x = n is not None

or

GLOBAL_OBJECT = ...

def is_some(n):
    GLOBAL_OBJECT.x = n is not None

As a general rule, to me it seems more likely that someone made a typo than that they misunderstood the fundamentals of Python semantics (thinking that Python has implicit returns when it does not). But I think you're right that if it's the last line of the function, the more likely typo is that they forgot to use a return statement; it's less likely that they wanted to assign the value to something if it's the last line of a function.

TL;DR: I'd also accept a PR making the error message adaptive here depending on whether it's the last line of a function or not 😄

[lolbinarycat]

As a general rule, to me it seems more likely that someone made a typo than that they misunderstood the fundamentals of Python semantics (thinking that Python has implicit returns when it does not).

missing the entire left-hand side is a pretty big typo, and python is very frequently used by beginner programmers and programmers who do not usually specialize in python (like me, i'm mostly a rust programmer, but i know just enough python to get by with basic tweaks)

[thejchap]

@MichaReiser @AlexWaygood looks like this one is up for grabs - would like to give it a shot (first time contributor here :)

[thejchap]

nevermind - missed this

[dhruvmanila]

Resolved in #12944. Sorry for the churn, @thejchap.