diff --git a/lib/membrane/children_spec.ex b/lib/membrane/children_spec.ex
index 7507da384..a5120180f 100644
--- a/lib/membrane/children_spec.ex
+++ b/lib/membrane/children_spec.ex
@@ -452,7 +452,9 @@ defmodule Membrane.ChildrenSpec do
       via_in(builder, :input)
     end
     |> Builder.finish_link(child_name)
-    |> then(&%Builder{&1 | children: [child_spec | &1.children]})
+    |> then(fn %Builder{} = builder ->
+      %Builder{builder | children: [child_spec | builder.children]}
+    end)
   end
 
   @doc """
@@ -465,7 +467,9 @@ defmodule Membrane.ChildrenSpec do
     :ok = validate_pad_name(pad)
 
     get_child({Membrane.Bin, :itself})
-    |> then(&%Builder{&1 | status: :from_pad, from_pad: pad, from_pad_props: %{}})
+    |> then(fn %Builder{} = builder ->
+      %Builder{builder | status: :from_pad, from_pad: pad, from_pad_props: %{}}
+    end)
   end
 
   @doc """
@@ -488,7 +492,9 @@ defmodule Membrane.ChildrenSpec do
     else
       via_out(builder, :output)
     end
-    |> then(&%Builder{&1 | status: :to_pad, to_pad: pad, to_pad_props: %{}})
+    |> then(fn %Builder{} = builder ->
+      %Builder{builder | status: :to_pad, to_pad: pad, to_pad_props: %{}}
+    end)
     |> get_child({Membrane.Bin, :itself})
   end
 
@@ -541,7 +547,7 @@ defmodule Membrane.ChildrenSpec do
           "Invalid link specification: input #{inspect(pad)} placed after another input"
   end
 
-  def via_in(%Builder{links: [%{to: {Membrane.Bin, :itself}} | _]}, pad, _props) do
+  def via_in(%Builder{links: [%{to: {Membrane.Bin, :itself}} | _rest]}, pad, _props) do
     raise ParentError,
           "Invalid link specification: input #{inspect(pad)} placed after bin's output"
   end
@@ -572,7 +578,9 @@ defmodule Membrane.ChildrenSpec do
     else
       via_out(builder, :output)
     end
-    |> then(&%Builder{&1 | status: :to_pad, to_pad: pad, to_pad_props: Enum.into(props, %{})})
+    |> then(fn %Builder{} = builder ->
+      %Builder{builder | status: :to_pad, to_pad: pad, to_pad_props: Enum.into(props, %{})}
+    end)
   end
 
   @doc """
@@ -598,7 +606,7 @@ defmodule Membrane.ChildrenSpec do
     raise ParentError, "Invalid link specification: output #{inspect(pad)} placed after an input"
   end
 
-  def via_out(%Builder{links: [%{to: {Membrane.Bin, :itself}} | _]}, pad, _props) do
+  def via_out(%Builder{links: [%{to: {Membrane.Bin, :itself}} | _rest]}, pad, _props) do
     raise ParentError,
           "Invalid link specification: output #{inspect(pad)} placed after bin's output"
   end
diff --git a/lib/membrane/core/child/pad_controller.ex b/lib/membrane/core/child/pad_controller.ex
index d3b1a588d..25c8791eb 100644
--- a/lib/membrane/core/child/pad_controller.ex
+++ b/lib/membrane/core/child/pad_controller.ex
@@ -61,7 +61,7 @@ defmodule Membrane.Core.Child.PadController do
           map | no_return
   def parse_pad_options!(pad_name, options, state) do
     {_pad_name, pad_spec} =
-      PadSpecHandler.get_pads(state) |> Enum.find(fn {k, _} -> k == pad_name end)
+      PadSpecHandler.get_pads(state) |> Enum.find(fn {k, _desc} -> k == pad_name end)
 
     bunch_field_specs =
       Bunch.KVList.map_values(pad_spec.options || [], &Keyword.take(&1, [:default]))
diff --git a/lib/membrane/core/child/pads_specs.ex b/lib/membrane/core/child/pads_specs.ex
index 61e1363b4..a646ab148 100644
--- a/lib/membrane/core/child/pads_specs.ex
+++ b/lib/membrane/core/child/pads_specs.ex
@@ -340,7 +340,7 @@ defmodule Membrane.Core.Child.PadsSpecs do
   def generate_docs_from_pads_specs(pads_specs) do
     pads_docs =
       pads_specs
-      |> Enum.sort_by(fn {_, config} -> config[:direction] end)
+      |> Enum.sort_by(fn {_pad_name, config} -> config[:direction] end)
       |> Enum.map(&generate_docs_from_pad_specs/1)
       |> Enum.reduce(fn x, acc ->
         quote do
diff --git a/lib/membrane/core/element.ex b/lib/membrane/core/element.ex
index 3631119e9..7d4ffb69b 100644
--- a/lib/membrane/core/element.ex
+++ b/lib/membrane/core/element.ex
@@ -102,6 +102,10 @@ defmodule Membrane.Core.Element do
     end
   end
 
+  # Suppress false positive dialyzer warnings resulting from 
+  # broken handling of opaque types - in this case MapSet.t() 
+  # https://github.com/elixir-lang/elixir/issues/14576
+  @dialyzer {:nowarn_function, do_init: 1}
   defp do_init(options) do
     Process.link(options.parent_supervisor)
 
@@ -141,9 +145,9 @@ defmodule Membrane.Core.Element do
     state =
       %State{
         module: options.module,
-        type: options.module.membrane_element_type(),
         name: options.name,
         parent_pid: options.parent,
+        type: options.module.membrane_element_type(),
         synchronization: %{
           parent_clock: options.parent_clock,
           timers: %{},
diff --git a/lib/membrane/core/element/action_handler.ex b/lib/membrane/core/element/action_handler.ex
index e4eb82b7f..c77dbbe5f 100644
--- a/lib/membrane/core/element/action_handler.ex
+++ b/lib/membrane/core/element/action_handler.ex
@@ -75,13 +75,13 @@ defmodule Membrane.Core.Element.ActionHandler do
   end
 
   @impl CallbackHandler
-  def handle_action({action, _}, :handle_init, _params, _state)
+  def handle_action({action, _arg}, :handle_init, _params, _state)
       when action not in [:latency, :notify_parent] do
     raise ActionError, action: action, reason: {:invalid_callback, :handle_init}
   end
 
   @impl CallbackHandler
-  def handle_action({action, _}, _cb, _params, %State{playback: playback})
+  def handle_action({action, _arg}, _cb, _params, %State{playback: playback})
       when playback != :playing and
              action in [
                :buffer,
@@ -291,12 +291,13 @@ defmodule Membrane.Core.Element.ActionHandler do
     actions
     |> Bunch.Enum.chunk_by_prev(
       fn
-        {:buffer, {pad, _}}, {:buffer, {pad, _}} -> true
+        {:buffer, {pad, _buffer1}}, {:buffer, {pad, _buffer2}} -> true
         _prev_action, _action -> false
       end,
       fn
-        [{:buffer, {pad, _}} | _] = buffers ->
-          {:buffer, {pad, buffers |> Enum.map(fn {_, {_, b}} -> [b] end) |> List.flatten()}}
+        [{:buffer, {pad, _buffer}} | _rest] = buffers ->
+          {:buffer,
+           {pad, buffers |> Enum.map(fn {:buffer, {_pad, b}} -> [b] end) |> List.flatten()}}
 
         [other] ->
           other
diff --git a/lib/membrane/core/element/auto_flow_controller.ex b/lib/membrane/core/element/auto_flow_controller.ex
index 36c6fc3e1..9621224e6 100644
--- a/lib/membrane/core/element/auto_flow_controller.ex
+++ b/lib/membrane/core/element/auto_flow_controller.ex
@@ -218,6 +218,10 @@ defmodule Membrane.Core.Element.AutoFlowController do
     |> Map.put(:popping_auto_flow_queue?, false)
   end
 
+  # Suppress false positive dialyzer warnings resulting from 
+  # broken handling of opaque types - in this case MapSet.t() 
+  # https://github.com/elixir-lang/elixir/issues/14576
+  @dialyzer {:nowarn_function, bump_demand: 1}
   defp bump_demand(state) do
     if state.effective_flow_control == :pull and
          state.satisfied_auto_output_pads == @empty_map_set do
diff --git a/lib/membrane/core/element/event_controller.ex b/lib/membrane/core/element/event_controller.ex
index c3e3a76c4..3496a4673 100644
--- a/lib/membrane/core/element/event_controller.ex
+++ b/lib/membrane/core/element/event_controller.ex
@@ -5,7 +5,6 @@ defmodule Membrane.Core.Element.EventController do
 
   use Bunch
 
-  alias Membrane.{Event, Pad, Sync}
   alias Membrane.Core.{CallbackHandler, Events, Message, Telemetry}
   alias Membrane.Core.Child.PadModel
 
@@ -19,6 +18,7 @@ defmodule Membrane.Core.Element.EventController do
   }
 
   alias Membrane.Core.Element.ManualFlowController.InputQueue
+  alias Membrane.{Event, Pad, Sync}
 
   require Membrane.Core.Child.PadModel
   require Membrane.Core.Message
diff --git a/lib/membrane/core/element/lifecycle_controller.ex b/lib/membrane/core/element/lifecycle_controller.ex
index 1a225ad71..825edabd9 100644
--- a/lib/membrane/core/element/lifecycle_controller.ex
+++ b/lib/membrane/core/element/lifecycle_controller.ex
@@ -73,7 +73,7 @@ defmodule Membrane.Core.Element.LifecycleController do
   end
 
   @spec handle_playing(State.t()) :: State.t()
-  def handle_playing(state) do
+  def handle_playing(%State{} = state) do
     Membrane.Logger.debug("Got play request")
 
     state =
diff --git a/lib/membrane/core/element/manual_flow_controller.ex b/lib/membrane/core/element/manual_flow_controller.ex
index be20a37d9..038b0486f 100644
--- a/lib/membrane/core/element/manual_flow_controller.ex
+++ b/lib/membrane/core/element/manual_flow_controller.ex
@@ -80,7 +80,7 @@ defmodule Membrane.Core.Element.ManualFlowController do
     |> handle_delayed_demands()
   end
 
-  defp do_supply_demand(pad_ref, state) do
+  defp do_supply_demand(pad_ref, %State{} = state) do
     # marking is state that actual demand supply has been started (note changing back to false when finished)
     state = %State{state | delay_demands?: true}
 
@@ -90,7 +90,7 @@ defmodule Membrane.Core.Element.ManualFlowController do
       InputQueue.take(pad_data.input_queue, pad_data.manual_demand_size)
 
     state = PadModel.set_data!(state, pad_ref, :input_queue, new_input_queue)
-    state = handle_input_queue_output(pad_ref, popped_data, state)
+    %State{} = state = handle_input_queue_output(pad_ref, popped_data, state)
     %State{state | delay_demands?: false}
   end
 
diff --git a/lib/membrane/core/element/playback_queue.ex b/lib/membrane/core/element/playback_queue.ex
index 52f6ad91d..e796f4ffa 100644
--- a/lib/membrane/core/element/playback_queue.ex
+++ b/lib/membrane/core/element/playback_queue.ex
@@ -12,7 +12,8 @@ defmodule Membrane.Core.Element.PlaybackQueue do
 
   @spec eval(State.t()) :: State.t()
   def eval(%State{playback_queue: playback_queue} = state) do
-    state =
+    %State{} =
+      state =
       playback_queue
       |> List.foldr(state, fn function, state -> function.(state) end)
 
diff --git a/lib/membrane/core/element/state.ex b/lib/membrane/core/element/state.ex
index f3f0a6348..35d1a44b5 100644
--- a/lib/membrane/core/element/state.ex
+++ b/lib/membrane/core/element/state.ex
@@ -15,15 +15,12 @@ defmodule Membrane.Core.Element.State do
 
   @type t :: %__MODULE__{
           module: module(),
-          type: Element.type(),
           name: Element.name(),
+          parent_pid: pid(),
+          playback: Membrane.Playback.t(),
+          type: Element.type(),
           internal_state: Element.state() | nil,
           pads_info: PadModel.pads_info() | nil,
-          pads_data: PadModel.pads_data() | nil,
-          parent_pid: pid(),
-          delay_demands?: boolean(),
-          delayed_demands: MapSet.t({Pad.ref(), :supply | :redemand}),
-          handle_demand_loop_counter: non_neg_integer(),
           synchronization: %{
             timers: %{Timer.id() => Timer.t()},
             parent_clock: Clock.t(),
@@ -31,22 +28,25 @@ defmodule Membrane.Core.Element.State do
             stream_sync: Sync.t(),
             clock: Clock.t() | nil
           },
-          auto_input_pads: [Pad.ref()],
+          delayed_demands: MapSet.t({Pad.ref(), :supply | :redemand}),
+          effective_flow_control: EffectiveFlowController.effective_flow_control(),
           initialized?: boolean(),
-          playback: Membrane.Playback.t(),
-          playback_queue: Membrane.Core.Element.PlaybackQueue.t(),
-          resource_guard: Membrane.ResourceGuard.t(),
-          subprocess_supervisor: pid(),
           terminating?: boolean(),
           setup_incomplete_returned?: boolean(),
-          effective_flow_control: EffectiveFlowController.effective_flow_control(),
+          delay_demands?: boolean(),
           popping_auto_flow_queue?: boolean(),
-          pads_to_snapshot: MapSet.t(),
           stalker: Membrane.Core.Stalker.t(),
+          resource_guard: Membrane.ResourceGuard.t(),
+          subprocess_supervisor: pid(),
+          handle_demand_loop_counter: non_neg_integer(),
+          pads_to_snapshot: MapSet.t(),
+          playback_queue: Membrane.Core.Element.PlaybackQueue.t(),
+          diamond_detection_state: DiamondDatectionState.t(),
+          pads_data: PadModel.pads_data() | nil,
           satisfied_auto_output_pads: MapSet.t(),
           awaiting_auto_input_pads: MapSet.t(),
-          resume_delayed_demands_loop_in_mailbox?: boolean(),
-          diamond_detection_state: DiamondDatectionState.t()
+          auto_input_pads: [Pad.ref()],
+          resume_delayed_demands_loop_in_mailbox?: boolean()
         }
 
   # READ THIS BEFORE ADDING NEW FIELD!!!
diff --git a/lib/membrane/core/element/stream_format_controller.ex b/lib/membrane/core/element/stream_format_controller.ex
index 87f617ff5..a282e90cc 100644
--- a/lib/membrane/core/element/stream_format_controller.ex
+++ b/lib/membrane/core/element/stream_format_controller.ex
@@ -5,7 +5,6 @@ defmodule Membrane.Core.Element.StreamFormatController do
 
   use Bunch
 
-  alias Membrane.{Pad, StreamFormat}
   alias Membrane.Core.{CallbackHandler, Telemetry}
   alias Membrane.Core.Child.PadModel
 
@@ -18,6 +17,7 @@ defmodule Membrane.Core.Element.StreamFormatController do
   }
 
   alias Membrane.Core.Element.ManualFlowController.InputQueue
+  alias Membrane.{Pad, StreamFormat}
 
   require Membrane.Core.Child.PadModel
   require Membrane.Core.Telemetry
diff --git a/lib/membrane/core/filter_aggregator/context.ex b/lib/membrane/core/filter_aggregator/context.ex
index 022c47f6d..8f0e96eb3 100644
--- a/lib/membrane/core/filter_aggregator/context.ex
+++ b/lib/membrane/core/filter_aggregator/context.ex
@@ -15,6 +15,10 @@ defmodule Membrane.Core.FilterAggregator.Context do
   @type action :: Element.Action.t() | Membrane.Core.FilterAggregator.InternalAction.t()
 
   @spec build_context!(Element.name(), module(), t()) :: t()
+  # Suppress false positive dialyzer warnings resulting from 
+  # broken handling of opaque types - in this case MapSet.t() 
+  # https://github.com/elixir-lang/elixir/issues/14576
+  @dialyzer {:nowarn_function, build_context!: 3}
   def build_context!(name, module, agg_ctx) do
     pad_descriptions = module.membrane_pads()
     pads = pad_descriptions |> MapSet.new(fn {k, _v} -> k end)
diff --git a/lib/membrane/core/parent/child_life_controller/crash_group_utils.ex b/lib/membrane/core/parent/child_life_controller/crash_group_utils.ex
index 3203dc9e0..aaf8d5f31 100644
--- a/lib/membrane/core/parent/child_life_controller/crash_group_utils.ex
+++ b/lib/membrane/core/parent/child_life_controller/crash_group_utils.ex
@@ -92,12 +92,14 @@ defmodule Membrane.Core.Parent.ChildLifeController.CrashGroupUtils do
 
     update_in(
       state.crash_groups[group.name],
-      &%CrashGroup{
-        &1
-        | detonating?: true,
-          crash_initiator: crash_initiator,
-          crash_reason: reason
-      }
+      fn %CrashGroup{} = group ->
+        %CrashGroup{
+          group
+          | detonating?: true,
+            crash_initiator: crash_initiator,
+            crash_reason: reason
+        }
+      end
     )
   end
 
diff --git a/lib/membrane/core/parent/child_life_controller/link_utils.ex b/lib/membrane/core/parent/child_life_controller/link_utils.ex
index 5d56be0b4..48aefe965 100644
--- a/lib/membrane/core/parent/child_life_controller/link_utils.ex
+++ b/lib/membrane/core/parent/child_life_controller/link_utils.ex
@@ -156,12 +156,14 @@ defmodule Membrane.Core.Parent.ChildLifeController.LinkUtils do
     links =
       Enum.map(
         links,
-        &%Link{
-          &1
-          | spec_ref: spec_ref,
-            from: resolve_endpoint(&1.from, state),
-            to: resolve_endpoint(&1.to, state)
-        }
+        fn %Link{} = link ->
+          %Link{
+            link
+            | spec_ref: spec_ref,
+              from: resolve_endpoint(link.from, state),
+              to: resolve_endpoint(link.to, state)
+          }
+        end
       )
 
     :ok = validate_links(links, state)
@@ -235,13 +237,12 @@ defmodule Membrane.Core.Parent.ChildLifeController.LinkUtils do
     end
   end
 
-  defp resolve_endpoint(endpoint, state) do
-    %Endpoint{child: child, pad_spec: pad_spec} = endpoint
-    child_data = Parent.ChildrenModel.get_child_data!(state, child)
-    pad_name = Pad.name_by_ref(pad_spec)
+  defp resolve_endpoint(%Endpoint{} = endpoint, state) do
+    child_data = Parent.ChildrenModel.get_child_data!(state, endpoint.child)
+    pad_name = Pad.name_by_ref(endpoint.pad_spec)
 
     withl pad: {:ok, pad_info} <- Keyword.fetch(child_data.module.membrane_pads(), pad_name),
-          ref: {:ok, ref} <- make_pad_ref(pad_spec, pad_info.availability) do
+          ref: {:ok, ref} <- make_pad_ref(endpoint.pad_spec, pad_info.availability) do
       %Endpoint{
         endpoint
         | pid: child_data.pid,
@@ -251,11 +252,12 @@ defmodule Membrane.Core.Parent.ChildLifeController.LinkUtils do
       }
     else
       pad: :error ->
-        raise LinkError, "Child #{inspect(child)} does not have pad #{inspect(pad_spec)}"
+        raise LinkError,
+              "Child #{inspect(endpoint.child)} does not have pad #{inspect(endpoint.pad_spec)}"
 
       ref: {:error, :invalid_availability} ->
         raise LinkError,
-              "Dynamic pad ref #{inspect(pad_spec)} passed for static pad of child #{inspect(child)}"
+              "Dynamic pad ref #{inspect(endpoint.pad_spec)} passed for static pad of child #{inspect(endpoint.child)}"
     end
   end
 
diff --git a/lib/membrane/core/parent/child_life_controller/startup_utils.ex b/lib/membrane/core/parent/child_life_controller/startup_utils.ex
index 766ddf610..0d6872cb7 100644
--- a/lib/membrane/core/parent/child_life_controller/startup_utils.ex
+++ b/lib/membrane/core/parent/child_life_controller/startup_utils.ex
@@ -172,7 +172,7 @@ defmodule Membrane.Core.Parent.ChildLifeController.StartupUtils do
     :ok
   end
 
-  defp start_child(child, node, syncs, log_metadata, group, state) do
+  defp start_child(%ChildEntry{} = child, node, syncs, log_metadata, group, state) do
     %ChildEntry{name: name, module: module, options: options} = child
 
     Membrane.Logger.debug(
diff --git a/lib/membrane/core/parent/specification_parser.ex b/lib/membrane/core/parent/specification_parser.ex
index 969c4bfc8..ff44f34c2 100644
--- a/lib/membrane/core/parent/specification_parser.ex
+++ b/lib/membrane/core/parent/specification_parser.ex
@@ -2,9 +2,9 @@ defmodule Membrane.Core.Parent.SpecificationParser do
   @moduledoc false
   use Bunch
 
+  alias Membrane.{ChildrenSpec, Element, Pad, ParentError}
   alias Membrane.Core.Parent.Link
   alias Membrane.Core.Parent.Link.Endpoint
-  alias Membrane.{ChildrenSpec, Element, Pad, ParentError}
 
   require Membrane.Logger
 
@@ -28,7 +28,7 @@ defmodule Membrane.Core.Parent.SpecificationParser do
         %ChildrenSpec.Builder{links: links, children: children, status: :done} = builder ->
           if links == [] and children == [] do
             Membrane.Logger.warning(
-              "The specification you have passed: #{builder} has no effect - it doesn't produce any children nor links."
+              "The specification you have passed: #{inspect(builder)} has no effect - it doesn't produce any children nor links."
             )
           end
 
diff --git a/lib/membrane/core/pipeline.ex b/lib/membrane/core/pipeline.ex
index a20a5bfe1..6f61fbab5 100644
--- a/lib/membrane/core/pipeline.ex
+++ b/lib/membrane/core/pipeline.ex
@@ -5,8 +5,8 @@ defmodule Membrane.Core.Pipeline do
   alias __MODULE__.{ActionHandler, State}
   alias Membrane.{Clock, ResourceGuard}
   alias Membrane.Core.{CallbackHandler, ProcessHelper, Stalker, SubprocessSupervisor}
-  alias Membrane.Core.Pipeline.CallbackContext
   alias Membrane.Core.Parent.{ChildLifeController, LifecycleController}
+  alias Membrane.Core.Pipeline.CallbackContext
   alias Membrane.Core.TimerController
 
   require Membrane.Core.Utils, as: Utils
diff --git a/lib/membrane/core/timer.ex b/lib/membrane/core/timer.ex
index bd4eab23f..d6a8575a0 100644
--- a/lib/membrane/core/timer.ex
+++ b/lib/membrane/core/timer.ex
@@ -40,7 +40,7 @@ defmodule Membrane.Core.Timer do
   end
 
   @spec update_ratio(t, Clock.ratio()) :: t
-  def update_ratio(timer, ratio) do
+  def update_ratio(%__MODULE__{} = timer, ratio) do
     %__MODULE__{timer | ratio: ratio}
   end
 
@@ -55,7 +55,7 @@ defmodule Membrane.Core.Timer do
     timer
   end
 
-  def tick(timer) do
+  def tick(%__MODULE__{} = timer) do
     %__MODULE__{
       id: id,
       interval: interval,
@@ -89,7 +89,7 @@ defmodule Membrane.Core.Timer do
     |> tick()
   end
 
-  def set_interval(timer, interval) do
+  def set_interval(%__MODULE__{} = timer, interval) do
     %__MODULE__{timer | interval: interval}
   end
 end
diff --git a/lib/membrane/element/with_input_pads.ex b/lib/membrane/element/with_input_pads.ex
index defa5a6f1..fddd78b17 100644
--- a/lib/membrane/element/with_input_pads.ex
+++ b/lib/membrane/element/with_input_pads.ex
@@ -8,8 +8,8 @@ defmodule Membrane.Element.WithInputPads do
   For more information on implementing elements, see `Membrane.Element.Base`.
   """
 
-  alias Membrane.Core.Child.PadsSpecs
   alias Membrane.{Buffer, Element, Pad}
+  alias Membrane.Core.Child.PadsSpecs
   alias Membrane.Element.CallbackContext
 
   @doc """
@@ -88,7 +88,7 @@ defmodule Membrane.Element.WithInputPads do
     PadsSpecs.def_pad(name, :input, spec, element_type)
   end
 
-  defmacro __using__(_) do
+  defmacro __using__(_element) do
     quote location: :keep do
       @behaviour unquote(__MODULE__)
 
diff --git a/lib/membrane/element/with_output_pads.ex b/lib/membrane/element/with_output_pads.ex
index 55eaf43fc..63be43e6c 100644
--- a/lib/membrane/element/with_output_pads.ex
+++ b/lib/membrane/element/with_output_pads.ex
@@ -51,7 +51,7 @@ defmodule Membrane.Element.WithOutputPads do
     PadsSpecs.def_pad(name, :output, spec, element_type)
   end
 
-  defmacro __using__(_) do
+  defmacro __using__(_element) do
     quote location: :keep do
       @behaviour unquote(__MODULE__)
 
diff --git a/lib/membrane/testing/dynamic_source.ex b/lib/membrane/testing/dynamic_source.ex
index b0d6ba96b..536112d1a 100644
--- a/lib/membrane/testing/dynamic_source.ex
+++ b/lib/membrane/testing/dynamic_source.ex
@@ -121,7 +121,9 @@ defmodule Membrane.Testing.DynamicSource do
   def handle_demand(pad, _size, :buffers, _ctx, %{type: :enum} = state) do
     output_for_pad = state.output_for_pad[pad]
 
-    if length(output_for_pad) > 0 do
+    if Enum.empty?(output_for_pad) do
+      {[end_of_stream: pad], state}
+    else
       [payload | rest] = output_for_pad
 
       {
@@ -131,8 +133,6 @@ defmodule Membrane.Testing.DynamicSource do
         ],
         Map.update!(state, :output_for_pad, &Map.put(&1, pad, rest))
       }
-    else
-      {[end_of_stream: pad], state}
     end
   end
 
diff --git a/lib/membrane/testing/pipeline.ex b/lib/membrane/testing/pipeline.ex
index b6af8ecf9..4b8975ef4 100644
--- a/lib/membrane/testing/pipeline.ex
+++ b/lib/membrane/testing/pipeline.ex
@@ -323,8 +323,8 @@ defmodule Membrane.Testing.Pipeline do
 
       module when is_atom(module) ->
         case Code.ensure_compiled(module) do
-          {:module, _} -> :ok
-          {:error, _} -> raise "Unknown module: #{inspect(module)}"
+          {:module, _module} -> :ok
+          {:error, _error} -> raise "Unknown module: #{inspect(module)}"
         end
 
         new_state = %State{
diff --git a/mix.exs b/mix.exs
index 00bd53cd3..99e6d319e 100644
--- a/mix.exs
+++ b/mix.exs
@@ -17,12 +17,6 @@ defmodule Membrane.Mixfile do
       source_url: link(),
       docs: docs(),
       aliases: [docs: ["docs", &copy_assets/1]],
-      preferred_cli_env: [
-        coveralls: :test,
-        "coveralls.detail": :test,
-        "coveralls.post": :test,
-        "coveralls.html": :test
-      ],
       test_coverage: [tool: ExCoveralls, test_task: "test"],
       deps: deps()
     ]
@@ -32,6 +26,17 @@ defmodule Membrane.Mixfile do
     [extra_applications: [:logger]]
   end
 
+  def cli do
+    [
+      preferred_envs: [
+        coveralls: :test,
+        "coveralls.detail": :test,
+        "coveralls.post": :test,
+        "coveralls.html": :test
+      ]
+    ]
+  end
+
   defp elixirc_paths(:test), do: ["lib", "test/support"]
   defp elixirc_paths(:benchmark), do: ["lib", "benchmark"]
   defp elixirc_paths(_env), do: ["lib"]
@@ -220,7 +225,7 @@ defmodule Membrane.Mixfile do
   end
 
   defp copy_assets(_args) do
-    File.cp_r("assets", "doc/assets", fn _source, _destination -> true end)
+    File.cp_r("assets", "doc/assets", on_conflict: fn _source, _destination -> true end)
   end
 
   defp package do
diff --git a/mix.lock b/mix.lock
index 7c6cad95e..aa6f8b6a0 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,12 +1,12 @@
 %{
   "bunch": {:hex, :bunch, "1.6.1", "5393d827a64d5f846092703441ea50e65bc09f37fd8e320878f13e63d410aec7", [:mix], [], "hexpm", "286cc3add551628b30605efbe2fca4e38cc1bea89bcd0a1a7226920b3364fe4a"},
   "bunt": {:hex, :bunt, "1.0.0", "081c2c665f086849e6d57900292b3a161727ab40431219529f13c4ddcf3e7a44", [:mix], [], "hexpm", "dc5f86aa08a5f6fa6b8096f0735c4e76d54ae5c9fa2c143e5a1fc7c1cd9bb6b5"},
-  "coerce": {:hex, :coerce, "1.0.1", "211c27386315dc2894ac11bc1f413a0e38505d808153367bd5c6e75a4003d096", [:mix], [], "hexpm", "b44a691700f7a1a15b4b7e2ff1fa30bebd669929ac8aa43cffe9e2f8bf051cf1"},
-  "credo": {:hex, :credo, "1.7.10", "6e64fe59be8da5e30a1b96273b247b5cf1cc9e336b5fd66302a64b25749ad44d", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "71fbc9a6b8be21d993deca85bf151df023a3097b01e09a2809d460348561d8cd"},
+  "coerce": {:hex, :coerce, "1.0.2", "5ef791040c92baaa5dd344887563faaeac6e6742573a167493294f8af3672bbe", [:mix], [], "hexpm", "0b3451c729571234fdac478636c298e71d1f2ce1243abed5fa43fa3181b980eb"},
+  "credo": {:hex, :credo, "1.7.14", "c7e75216cea8d978ba8c60ed9dede4cc79a1c99a266c34b3600dd2c33b96bc92", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "12a97d6bb98c277e4fb1dff45aaf5c137287416009d214fb46e68147bd9e0203"},
   "dialyxir": {:hex, :dialyxir, "1.4.5", "ca1571ac18e0f88d4ab245f0b60fa31ff1b12cbae2b11bd25d207f865e8ae78a", [:mix], [{:erlex, ">= 0.2.7", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "b0fb08bb8107c750db5c0b324fa2df5ceaa0f9307690ee3c1f6ba5b9eb5d35c3"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.44", "f20830dd6b5c77afe2b063777ddbbff09f9759396500cdbe7523efd58d7a339c", [:mix], [], "hexpm", "4778ac752b4701a5599215f7030989c989ffdc4f6df457c5f36938cc2d2a2750"},
   "erlex": {:hex, :erlex, "0.2.7", "810e8725f96ab74d17aac676e748627a07bc87eb950d2b83acd29dc047a30595", [:mix], [], "hexpm", "3ed95f79d1a844c3f6bf0cea61e0d5612a42ce56da9c03f01df538685365efb0"},
-  "ex_doc": {:hex, :ex_doc, "0.39.1", "e19d356a1ba1e8f8cfc79ce1c3f83884b6abfcb79329d435d4bbb3e97ccc286e", [:mix], [{:earmark_parser, "~> 1.4.44", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "8abf0ed3e3ca87c0847dfc4168ceab5bedfe881692f1b7c45f4a11b232806865"},
+  "ex_doc": {:hex, :ex_doc, "0.39.3", "519c6bc7e84a2918b737aec7ef48b96aa4698342927d080437f61395d361dcee", [:mix], [{:earmark_parser, "~> 1.4.44", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "0590955cf7ad3b625780ee1c1ea627c28a78948c6c0a9b0322bd976a079996e1"},
   "excoveralls": {:hex, :excoveralls, "0.18.3", "bca47a24d69a3179951f51f1db6d3ed63bca9017f476fe520eb78602d45f7756", [:mix], [{:castore, "~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "746f404fcd09d5029f1b211739afb8fb8575d775b21f6a3908e7ce3e640724c6"},
   "file_system": {:hex, :file_system, "1.0.1", "79e8ceaddb0416f8b8cd02a0127bdbababe7bf4a23d2a395b983c1f8b3f73edd", [:mix], [], "hexpm", "4414d1f38863ddf9120720cd976fce5bdde8e91d8283353f0e31850fa89feb9e"},
   "jason": {:hex, :jason, "1.4.4", "b9226785a9aa77b6857ca22832cffa5d5011a667207eb2a0ad56adb5db443b8a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "c5eb0cab91f094599f94d55bc63409236a8ec69a21a67814529e8d5f6cc90b3b"},
diff --git a/test/membrane/core/element/input_queue_test.exs b/test/membrane/core/element/input_queue_test.exs
index 0bef78f60..8f852fa4a 100644
--- a/test/membrane/core/element/input_queue_test.exs
+++ b/test/membrane/core/element/input_queue_test.exs
@@ -256,7 +256,7 @@ defmodule Membrane.Core.Element.InputQueueTest do
     end
 
     test "set `size` to 0 when there are not enough buffers", context do
-      {_, %{size: new_size}} = InputQueue.take(context.input_queue, 10)
+      {_output, %{size: new_size}} = InputQueue.take(context.input_queue, 10)
 
       assert new_size == 0
     end
diff --git a/test/membrane/core/element/stream_format_controller_test.exs b/test/membrane/core/element/stream_format_controller_test.exs
index 766bb01d2..6b9955e1d 100644
--- a/test/membrane/core/element/stream_format_controller_test.exs
+++ b/test/membrane/core/element/stream_format_controller_test.exs
@@ -2,9 +2,9 @@ defmodule Membrane.Core.Element.StreamFormatControllerTest do
   use ExUnit.Case, async: true
 
   alias Membrane.Buffer
-  alias Membrane.Core.Message
   alias Membrane.Core.Element.{AtomicDemand, State}
   alias Membrane.Core.Element.ManualFlowController.InputQueue
+  alias Membrane.Core.Message
   alias Membrane.Core.SubprocessSupervisor
   alias Membrane.StreamFormat.Mock, as: MockStreamFormat
   alias Membrane.Support.DemandsTest.Filter
diff --git a/test/membrane/integration/stalker_test.exs b/test/membrane/integration/stalker_test.exs
index 92ff04047..66e4cab02 100644
--- a/test/membrane/integration/stalker_test.exs
+++ b/test/membrane/integration/stalker_test.exs
@@ -114,7 +114,7 @@ defmodule Membrane.Integration.StalkerTest do
 
     # we should receive some metrics
     assert_receive {:metrics, metrics, _timestamp}, 2000
-    assert length(metrics) > 0
+    refute Enum.empty?(metrics)
 
     stop_children(pipeline)
 
diff --git a/test/membrane/integration/sync_test.exs b/test/membrane/integration/sync_test.exs
index dd1fe6639..cec933df6 100644
--- a/test/membrane/integration/sync_test.exs
+++ b/test/membrane/integration/sync_test.exs
@@ -4,8 +4,8 @@ defmodule Membrane.Integration.SyncTest do
   import Membrane.ChildrenSpec
   import Membrane.Testing.Assertions
 
-  alias Membrane.{Testing, Time}
   alias Membrane.Support.{Sync, TestBins}
+  alias Membrane.{Testing, Time}
   alias TestBins.TestFilter
 
   @tick_number_error 5
@@ -122,7 +122,7 @@ defmodule Membrane.Integration.SyncTest do
 
     assert {:error, reason} = Testing.Pipeline.start_link_supervised(options)
 
-    assert {%Membrane.ParentError{}, _} = reason
+    assert {%Membrane.ParentError{}, _stacktrace} = reason
   end
 
   test "synchronization inside a bin is possible" do
diff --git a/test/membrane/integration/sync_test/ticking_pace.exs b/test/membrane/integration/sync_test/ticking_pace.exs
index 1c1af3ced..a8c66d433 100644
--- a/test/membrane/integration/sync_test/ticking_pace.exs
+++ b/test/membrane/integration/sync_test/ticking_pace.exs
@@ -29,7 +29,7 @@ defmodule Membrane.Integration.SyncTest.TickingPace do
     %{synchronization: %{clock_provider: %{clock: original_clock, provider: :sink}}} =
       :sys.get_state(pipeline)
 
-    for _ <- 1..tries do
+    for _i <- 1..tries do
       send(original_clock, {:membrane_clock_update, reported_interval})
       Process.sleep(actual_report_interval)
     end
diff --git a/test/membrane/telemetry_test.exs b/test/membrane/telemetry_test.exs
index e87e2c060..626ffb211 100644
--- a/test/membrane/telemetry_test.exs
+++ b/test/membrane/telemetry_test.exs
@@ -103,14 +103,14 @@ defmodule Membrane.TelemetryTest do
 
         assert_receive {^ref, :telemetry_ack,
                         {[:membrane, :element, ^span, :start], results,
-                         %{component_path: [_, ^element_type]}}},
+                         %{component_path: [_pipeline, ^element_type]}}},
                        1000
 
         assert results.monotonic_time
 
         assert_receive {^ref, :telemetry_ack,
                         {[:membrane, :element, ^span, :stop], results,
-                         %{component_path: [_, ^element_type]} = metadata}},
+                         %{component_path: [_pipeline, ^element_type]} = metadata}},
                        1000
 
         assert results.duration >= 0
@@ -215,14 +215,14 @@ defmodule Membrane.TelemetryTest do
                  from: ":filter",
                  pad_from: ":output",
                  pad_to: ":input",
-                 parent_component_path: _,
+                 parent_component_path: _path,
                  to: ":sink"
                },
                %{
                  from: ":source",
                  pad_from: ":output",
                  pad_to: ":input",
-                 parent_component_path: _,
+                 parent_component_path: _path,
                  to: ":filter"
                }
              ] = Enum.sort([link1.value, link2.value])
@@ -241,7 +241,7 @@ defmodule Membrane.TelemetryTest do
     test "Buffer", %{child_spec: child_spec} do
       ref = setup_pipeline_for(:buffer, child_spec)
 
-      for _ <- 1..3 do
+      for _i <- 1..3 do
         assert_receive {^ref, :telemetry_ack,
                         {[:membrane, :datapoint, :buffer], measurement, metadata}}
 
diff --git a/test/support/child_removal_test/pipeline.ex b/test/support/child_removal_test/pipeline.ex
index 9b7c70b35..f9cc11db2 100644
--- a/test/support/child_removal_test/pipeline.ex
+++ b/test/support/child_removal_test/pipeline.ex
@@ -67,7 +67,7 @@ defmodule Membrane.Support.ChildRemovalTest.Pipeline do
 
   defp maybe_add_extra_source(children, _opts), do: children
 
-  defp maybe_add_extra_source_link(links, %{extra_source: _}) do
+  defp maybe_add_extra_source_link(links, %{extra_source: _source}) do
     [
       get_child(:extra_source) |> via_in(:input2, target_queue_size: 10) |> get_child(:filter3)
       | links