Ignore PredicateFunctionNames when is impl

[quangngd]

Overview

• Closes Predicate callbacks from behavior are not ignored #1108

Impl details

If any :def, :defp, :defmacro is preceded with :impl, we ignore.

Code is mostly inspired from the impl of Specs

[rrrene]

I like this in principle and will add suggestions later this week. 🎉

[rrrene]

The proposed change yields a couple of false negatives which we should iron out before I review this PR:

Suggested change

	test "it should report a violation with false negatives" do
	"""
	defmodule FooImpl do
	def impl(false), do: false
	def impl(true), do: true
	def is_bar do
	end
	end
	"""
	|> to_source_file
	|> run_check(@described_check)
	|> assert_issue()
	end
	test "it should report a violation with false negatives /2" do
	"""
	defmodule FooImpl do
	impl(true)
	def is_bar do
	end
	end
	"""
	|> to_source_file
	|> run_check(@described_check)
	|> assert_issue()
	end
	test "it should report a violation with false negatives /3" do
	"""
	defmodule Foo do
	@impl is_bar(a)
	end
	defmodule FooImpl do
	def is_bar do
	end
	end
	"""
	|> to_source_file
	|> run_check(@described_check)
	|> assert_issue()
	end
	test "it should report a violation with false negatives /4" do
	"""
	defmodule Foo do
	@impl true
	end
	defmodule FooImpl do
	def is_bar do
	end
	end
	"""
	|> to_source_file
	|> run_check(@described_check)
	|> assert_issue()
	end

[quangngd]

Sure! I took another look and came up with some changes.

[rrrene]

Two more nitpicks, than we should be ready to merge 👍

[rrrene]

Let's rename this atom to something more descriptive, like :record_next_definition, so that it tells what it does.

[quangngd]

updated

[rrrene]

This traverses the whole file for @impl even if there is no need.

I would love for this logic to be reversed:

issue_candidates = Credo.Code.prewalk(source_file, &traverse(&1, &2, issue_meta))

if issue_candidates == [] do
  []
else
  impl_list = Credo.Code.prewalk(source_file, &find_impls(&1, &2))

  # and then reject the issue_candidates that have an `@impl`
end

WDYT?

[quangngd]

refactored

[rrrene]

@quangngd Thx! ✌️