Fix logger dialyzer warnings

Author: fishcakez

lib/logger/lib/logger/app.ex

@@ -50,7 +50,7 @@ defmodule Logger.App do
   def stop() do
     set = Application.get_env(:logger, :deleted_handlers)
     Application.put_env(:logger, :deleted_handlers, HashSet.new)
-    Application.stop(:logger)
+    _ = Application.stop(:logger)
     Enum.each(set, &:error_logger.add_report_handler/1)
   end
 
@@ -66,4 +66,4 @@ defmodule Logger.App do
       deleted
     end
   end
-end
+end

lib/logger/lib/logger/config.ex

@@ -76,9 +76,7 @@ defmodule Logger.Config do
       ^mode ->
         {:ok, state}
       new_mode ->
-        state = %{state | mode: new_mode}
-        persist(state)
-        {:ok, state}
+        {:ok, persist(%{state | mode: new_mode})}
     end
   end
 

lib/logger/lib/logger/error_handler.ex

@@ -86,7 +86,7 @@ defmodule Logger.ErrorHandler do
       match?({^m, ^s, _}, last_time) ->
         state
       true ->
-        if dropped > 0 do
+        _ = if dropped > 0 do
           Logger.warn "Logger dropped #{dropped} OTP/SASL messages as it " <>
                       "exceeded the amount of #{threshold} messages/second"
         end

lib/logger/lib/logger/formatter.ex

@@ -40,9 +40,12 @@ defmodule Logger.Formatter do
   value.
   """
 
+  @type time :: {{1970..10000, 1..12, 1..31}, {0..23, 0..59, 0..59, 0..999}}
+  @type pattern :: :date | :level | :levelpad | :message | :metadata | :node | :time
   @valid_patterns [:time, :date, :message, :level, :node, :metadata, :levelpad]
   @default_pattern "\n$time $metadata[$level] $levelpad$message\n"
 
+
   @doc ~S"""
   Compiles a format string into an array that the `format/5` can handle.
 
@@ -55,7 +58,7 @@ defmodule Logger.Formatter do
       iex> Logger.Formatter.compile("$time $metadata [$level] $message\n")
       [:time, " ", :metadata, " [", :level, "] ", :message, "\n"]
   """
-  @spec compile(binary | nil) :: list()
+  @spec compile(binary | nil) :: [pattern | binary]
   @spec compile({atom, atom}) :: {atom, atom}
 
   def compile(nil), do: compile(@default_pattern)
@@ -80,6 +83,8 @@ defmodule Logger.Formatter do
   metadata listdict and returns a properly formatted string.
   """
 
+  @spec format({atom, atom} | [pattern | binary], Logger.level, Logger.message, time, Keyword.t) ::
+    IO.chardata
   def format({mod, fun}, level, msg, ts, md) do
     apply(mod, fun, [level, msg, ts, md])
   end

lib/logger/lib/logger/watcher.ex

@@ -89,13 +89,13 @@ defmodule Logger.Watcher do
   end
 
   def handle_info({:gen_event_EXIT, handler, reason}, {mod, handler, _} = state) do
-    Logger.error "GenEvent handler #{inspect handler} installed at #{inspect mod}\n" <>
+    _ = Logger.error "GenEvent handler #{inspect handler} installed at #{inspect mod}\n" <>
                  "** (exit) #{format_exit(reason)}"
     {:stop, reason, state}
   end
 
   def handle_info({:DOWN, ref, _, _, reason}, {mod, handler, ref} = state) do
-    Logger.error "GenEvent handler #{inspect handler} installed at #{inspect mod}\n" <>
+    _ = Logger.error "GenEvent handler #{inspect handler} installed at #{inspect mod}\n" <>
                  "** (exit) #{format_exit(reason)}"
     {:stop, reason, state}
   end