Enforce stricter slice operations

Rule request

Thesis

The list has a set of methods that duplicates operations that you can do with + operator or slices:

# bad
items += [item]
# good
items.append(item)

# bad
items = [item] + items
# good
items.insert(0, item)

# bad
items += other
# good
items.extend(other)

# bad
items = items[::-1]
# good
items.reverse()

# bad
items = sorted(items)
# good
items.sort()

# bad
other = items[:]
# good
other = items.copy()

# bad
items[:] = []
# good
items.clear()

# bad
items = items[:-1]
# good
items.pop()

Reasoning

We have two ways to do something. Let’s prefer a more descriptive way.

This issue contains a lot of related cases. Consider splitting it by smaller ones.

[sobolevn]

Let’s implement several rules that are not bound to types:

• items[::-1] should not be used. Use reversed or .reverse()
• items[:] should not be used. Use .copy()
• items = items[:-1] should not be used. Use items.pop()

@orsinium as always - awesome suggestions! Thanks!

[orsinium]

Hmmm, that gives me an idea for one more rule. I’ve made #1071. Thank you, @Eric4Jiang!