diff --git a/config/.credo.exs b/.credo.exs
similarity index 60%
rename from config/.credo.exs
rename to .credo.exs
index a358359..6ae1554 100644
--- a/config/.credo.exs
+++ b/.credo.exs
@@ -9,7 +9,10 @@
       checks: [
         {Credo.Check.Consistency.TabsOrSpaces},
         {Credo.Check.Design.AliasUsage, false},
-        {Credo.Check.Readability.MaxLineLength, priority: :low, max_length: 100}
+        {Credo.Check.Readability.MaxLineLength, priority: :low, max_length: 100},
+        {Credo.Check.Readability.PipeIntoAnonymousFunctions, false},
+        # This rule incorrectly flags uses of Witchcraft.Semigroupoid.apply/2
+        {Credo.Check.Refactor.Apply, false}
       ]
     }
   ]
diff --git a/.tool-versions b/.tool-versions
index 5305266..05efa3e 100644
--- a/.tool-versions
+++ b/.tool-versions
@@ -1,2 +1,2 @@
-erlang 24.0.5
-elixir 1.12.2
+erlang 24.2
+elixir 1.13.2
\ No newline at end of file
diff --git a/config/config.exs b/config/config.exs
deleted file mode 100644
index 5767341..0000000
--- a/config/config.exs
+++ /dev/null
@@ -1,30 +0,0 @@
-# This file is responsible for configuring your application
-# and its dependencies with the aid of the Mix.Config module.
-use Mix.Config
-
-# This configuration is loaded before any dependency and is restricted
-# to this project. If another project depends on this project, this
-# file won't be loaded nor affect the parent project. For this reason,
-# if you want to provide default values for your application for
-# 3rd-party users, it should be done in your "mix.exs" file.
-
-# You can configure for your application as:
-#
-#     config :witchcraft, key: :value
-#
-# And access this configuration in your application as:
-#
-#     Application.get_env(:witchcraft, :key)
-#
-# Or configure a 3rd-party app:
-#
-#     config :logger, level: :info
-#
-
-# It is also possible to import configuration files, relative to this
-# directory. For example, you can emulate configuration per environment
-# by uncommenting the line below and defining dev.exs, test.exs and such.
-# Configuration from the imported file will override the ones defined
-# here (which is why it is important to import them last).
-#
-#     import_config "#{Mix.env}.exs"
diff --git a/lib/witchcraft/foldable.ex b/lib/witchcraft/foldable.ex
index 221264d..189a91b 100644
--- a/lib/witchcraft/foldable.ex
+++ b/lib/witchcraft/foldable.ex
@@ -54,9 +54,9 @@ defclass Witchcraft.Foldable do
     ## Examples
 
         iex> sum = fn xs -> right_fold(xs, 0, &+/2) end
-        ...> sum.([1, 2, 3])
+        iex> sum.([1, 2, 3])
         6
-        ...> sum.([4, 5, 6])
+        iex> sum.([4, 5, 6])
         15
 
     """
@@ -120,9 +120,9 @@ defclass Witchcraft.Foldable do
   ## Examples
 
       iex> sum = fn xs -> right_fold(xs, 0, &+/2) end
-      ...> sum.([1, 2, 3])
+      iex> sum.([1, 2, 3])
       6
-      ...> sum.([4, 5, 6])
+      iex> sum.([4, 5, 6])
       15
 
       iex> left_fold([1, 2, 3], [], fn(acc, x) -> [x | acc] end)
@@ -265,7 +265,7 @@ defclass Witchcraft.Foldable do
   ## Examples
 
       iex> use Witchcraft.Foldable
-      ...> length(%{})
+      iex> length(%{})
       0
       iex> length(%{a: 1, b: 2})
       2
@@ -356,9 +356,9 @@ defclass Witchcraft.Foldable do
   ## Examples
 
       iex> use Witchcraft.Foldable
-      ...> max([2, 3, 1])
+      iex> max([2, 3, 1])
       3
-      ...> max([[4], [1, 2, 3, 4]])
+      iex> max([[4], [1, 2, 3, 4]])
       [4]
 
       %BinaryTree{
@@ -414,9 +414,9 @@ defclass Witchcraft.Foldable do
   ## Examples
 
       iex> use Witchcraft.Foldable
-      ...> min([2, 3, 1])
+      iex> min([2, 3, 1])
       1
-      ...> min([[4], [1, 2, 3, 4]])
+      iex> min([[4], [1, 2, 3, 4]])
       [1, 2, 3, 4]
 
       %BinaryTree{
@@ -614,7 +614,7 @@ defclass Witchcraft.Foldable do
   ## Examples
 
       iex> import Integer
-      ...> all?([1, 2, 3], &is_odd/1)
+      iex> all?([1, 2, 3], &is_odd/1)
       false
 
       %BinaryTree{
@@ -668,7 +668,7 @@ defclass Witchcraft.Foldable do
   ## Examples
 
       iex> require Integer
-      ...> any?([1, 2, 3], &Integer.is_odd/1)
+      iex> any?([1, 2, 3], &Integer.is_odd/1)
       true
 
       %BinaryTree{
diff --git a/mix.exs b/mix.exs
index da939d9..f715c45 100644
--- a/mix.exs
+++ b/mix.exs
@@ -6,9 +6,10 @@ defmodule Witchcraft.Mixfile do
       app: :witchcraft,
       aliases: aliases(),
       deps: deps(),
+      preferred_cli_env: [quality: :test],
 
       # Versions
-      version: "1.0.3",
+      version: "1.0.4",
       elixir: "~> 1.9",
 
       # Docs
diff --git a/mix.lock b/mix.lock
index 93670db..ef6e3c5 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,20 +1,21 @@
 %{
   "benchfella": {:hex, :benchfella, "0.3.5", "b2122c234117b3f91ed7b43b6e915e19e1ab216971154acd0a80ce0e9b8c05f5", [:mix], [], "hexpm", "23f27cbc482cbac03fc8926441eb60a5e111759c17642bac005c3225f5eb809d"},
   "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm", "7af5c7e09fe1d40f76c8e4f9dd2be7cebd83909f31fee7cd0e9eadc567da8353"},
-  "credo": {:hex, :credo, "1.5.5", "e8f422026f553bc3bebb81c8e8bf1932f498ca03339856c7fec63d3faac8424b", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2.8", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "dd8623ab7091956a855dc9f3062486add9c52d310dfd62748779c4315d8247de"},
+  "credo": {:hex, :credo, "1.6.2", "2f82b29a47c0bb7b72f023bf3a34d151624f1cbe1e6c4e52303b05a11166a701", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2.8", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "ae9dc112bc368e7b145c547bec2ed257ef88955851c15057c7835251a17211c6"},
   "dialyxir": {:hex, :dialyxir, "1.1.0", "c5aab0d6e71e5522e77beff7ba9e08f8e02bad90dfbeffae60eaf0cb47e29488", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "07ea8e49c45f15264ebe6d5b93799d4dd56a44036cf42d0ad9c960bc266c0b9a"},
-  "earmark": {:hex, :earmark, "1.4.14", "d04572cef64dd92726a97d92d714e38d6e130b024ea1b3f8a56e7de66ec04e50", [:mix], [{:earmark_parser, ">= 1.4.12", [hex: :earmark_parser, repo: "hexpm", optional: false]}], "hexpm", "df338b8b1852ee425180b276c56c6941cb12220e04fe8718fe4acbdd35fd699f"},
-  "earmark_parser": {:hex, :earmark_parser, "1.4.12", "b245e875ec0a311a342320da0551da407d9d2b65d98f7a9597ae078615af3449", [:mix], [], "hexpm", "711e2cc4d64abb7d566d43f54b78f7dc129308a63bc103fbd88550d2174b3160"},
+  "earmark": {:hex, :earmark, "1.4.20", "d5097b1c7417a03c73a2985fcf01c3f72192c427b8a498719737dca5273938cb", [:mix], [{:earmark_parser, "== 1.4.18", [hex: :earmark_parser, repo: "hexpm", optional: false]}], "hexpm", "7be744242dbde74c858279f4a65d9d31f37d163190d739340015c30038c1edb3"},
+  "earmark_parser": {:hex, :earmark_parser, "1.4.18", "e1b2be73eb08a49fb032a0208bf647380682374a725dfb5b9e510def8397f6f2", [:mix], [], "hexpm", "114a0e85ec3cf9e04b811009e73c206394ffecfcc313e0b346de0d557774ee97"},
   "erlex": {:hex, :erlex, "0.2.6", "c7987d15e899c7a2f34f5420d2a2ea0d659682c06ac607572df55a43753aa12e", [:mix], [], "hexpm", "2ed2e25711feb44d52b17d2780eabf998452f6efda104877a3881c2f8c0c0c75"},
-  "ex_doc": {:hex, :ex_doc, "0.23.0", "a069bc9b0bf8efe323ecde8c0d62afc13d308b1fa3d228b65bca5cf8703a529d", [:mix], [{:earmark_parser, "~> 1.4.0", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm", "f5e2c4702468b2fd11b10d39416ddadd2fcdd173ba2a0285ebd92c39827a5a16"},
+  "ex_doc": {:hex, :ex_doc, "0.26.0", "1922164bac0b18b02f84d6f69cab1b93bc3e870e2ad18d5dacb50a9e06b542a3", [:mix], [{:earmark_parser, "~> 1.4.0", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1", [hex: :makeup_erlang, repo: "hexpm", optional: false]}], "hexpm", "2775d66e494a9a48355db7867478ffd997864c61c65a47d31c4949459281c78d"},
   "exceptional": {:hex, :exceptional, "2.1.3", "cb17cb9b7c4882e763b82db08ba317678157ca95970fae96b31b3c90f5960c3d", [:mix], [], "hexpm", "59d67ae2df6784e7a957087742ae9011f220c3d1523706c5cd7ee0741bca5897"},
   "file_system": {:hex, :file_system, "0.2.10", "fb082005a9cd1711c05b5248710f8826b02d7d1784e7c3451f9c1231d4fc162d", [:mix], [], "hexpm", "41195edbfb562a593726eda3b3e8b103a309b733ad25f3d642ba49696bf715dc"},
   "inch_ex": {:hex, :inch_ex, "2.0.0", "24268a9284a1751f2ceda569cd978e1fa394c977c45c331bb52a405de544f4de", [:mix], [{:bunt, "~> 0.2", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "96d0ec5ecac8cf63142d02f16b7ab7152cf0f0f1a185a80161b758383c9399a8"},
-  "jason": {:hex, :jason, "1.2.2", "ba43e3f2709fd1aa1dce90aaabfd039d000469c05c56f0b8e31978e03fa39052", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "18a228f5f0058ee183f29f9eae0805c6e59d61c3b006760668d8d18ff0d12179"},
+  "jason": {:hex, :jason, "1.3.0", "fa6b82a934feb176263ad2df0dbd91bf633d4a46ebfdffea0c8ae82953714946", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "53fc1f51255390e0ec7e50f9cb41e751c260d065dcba2bf0d08dc51a4002c2ac"},
   "makeup": {:hex, :makeup, "1.0.5", "d5a830bc42c9800ce07dd97fa94669dfb93d3bf5fcf6ea7a0c67b2e0e4a7f26c", [:mix], [{:nimble_parsec, "~> 0.5 or ~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "cfa158c02d3f5c0c665d0af11512fed3fba0144cf1aadee0f2ce17747fba2ca9"},
-  "makeup_elixir": {:hex, :makeup_elixir, "0.15.1", "b5888c880d17d1cc3e598f05cdb5b5a91b7b17ac4eaf5f297cb697663a1094dd", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.1", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "db68c173234b07ab2a07f645a5acdc117b9f99d69ebf521821d89690ae6c6ec8"},
-  "nimble_parsec": {:hex, :nimble_parsec, "1.1.0", "3a6fca1550363552e54c216debb6a9e95bd8d32348938e13de5eda962c0d7f89", [:mix], [], "hexpm", "08eb32d66b706e913ff748f11694b17981c0b04a33ef470e33e11b3d3ac8f54b"},
+  "makeup_elixir": {:hex, :makeup_elixir, "0.15.2", "dc72dfe17eb240552857465cc00cce390960d9a0c055c4ccd38b70629227e97c", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.1", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "fd23ae48d09b32eff49d4ced2b43c9f086d402ee4fd4fcb2d7fad97fa8823e75"},
+  "makeup_erlang": {:hex, :makeup_erlang, "0.1.1", "3fcb7f09eb9d98dc4d208f49cc955a34218fc41ff6b84df7c75b3e6e533cc65f", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "174d0809e98a4ef0b3309256cbf97101c6ec01c4ab0b23e926a9e17df2077cbb"},
+  "nimble_parsec": {:hex, :nimble_parsec, "1.2.0", "b44d75e2a6542dcb6acf5d71c32c74ca88960421b6874777f79153bbbbd7dccc", [:mix], [], "hexpm", "52b2871a7515a5ac49b00f214e4165a40724cf99798d8e4a65e4fd64ebd002c1"},
   "operator": {:hex, :operator, "0.2.1", "4572312bbd3e63a5c237bf15c3a7670d568e3651ea744289130780006e70e5f5", [:mix], [], "hexpm", "1990cc6dc651d7fff04636eef06fc64e6bc1da83a1da890c08ca3432e17e267a"},
-  "quark": {:hex, :quark, "2.3.1", "c205db217f0b42a3b2d7b828d85d9421c979446b3ef2c407092f93a2f768c48c", [:mix], [], "hexpm", "9db2b481cbdef445174f24af6092a6397d98fb0bd4f518b88f90e4d0c2235be0"},
-  "type_class": {:hex, :type_class, "1.2.5", "b972bb22202e801d83e8670228d9a1476cd2c9fc7da00b7039b19d6d06b17905", [:mix], [{:exceptional, "~> 2.1", [hex: :exceptional, repo: "hexpm", optional: false]}], "hexpm", "554cf5c49e92d3a371b85239ad842b2e69d034fed65921f4f99d7d910b6c50fe"},
+  "quark": {:hex, :quark, "2.3.2", "066e0d431440d077684469967f54d732443ea2a48932e0916e974633e8b39c95", [:mix], [], "hexpm", "2f6423779b02afe7e3e4af3cfecfcd94572f2051664d4d8329ffa872d24b10a8"},
+  "type_class": {:hex, :type_class, "1.2.8", "349db84be8c664e119efaae1a09a44b113bc8e81af1d032f4e3e38feef4fac32", [:mix], [{:exceptional, "~> 2.1", [hex: :exceptional, repo: "hexpm", optional: false]}], "hexpm", "bb93de2cacfd6f0ee43f4616f7a139816a73deba4ae8ee3364bcfa4abe3eef3e"},
 }
diff --git a/test/do_notation_test.exs b/test/do_notation_test.exs
index 3987bd0..23cae90 100644
--- a/test/do_notation_test.exs
+++ b/test/do_notation_test.exs
@@ -121,7 +121,7 @@ defmodule Witchcraft.DoNotationTest do
         b <- [3, 4]
         let [h | _] = [a * b]
         c <- [a, b, h]
-        let tens = c * 10
+        let _tens = c * 10
         d <- [c - 1, c + 1]
         [a, b, c, d]
       end