Try dialyzer on travis

.travis.yml

@@ -8,7 +8,7 @@ cache:
 
 elixir:
   - 1.4
-  - 1.5.0-rc.1
+  - 1.5
 
 otp_release:
   - 18.3
@@ -21,3 +21,4 @@ install:
 
 script:
   - mix test
+  - mix dialyzer --halt-exit-status

dialyzer.ignore

@@ -0,0 +1,5 @@
+Unknown function 'Elixir.Jason.Encoder.Function':'__impl__'/1
+Unknown function 'Elixir.Jason.Encoder.PID':'__impl__'/1
+Unknown function 'Elixir.Jason.Encoder.Port':'__impl__'/1
+Unknown function 'Elixir.Jason.Encoder.Reference':'__impl__'/1
+Unknown function 'Elixir.Jason.Encoder.Tuple':'__impl__'/1

lib/decoder.ex

@@ -606,8 +606,8 @@ defmodule Jason.Decoder do
       token_error(token, skip)
   end
 
-  defp error(<<_rest::bits>>, original, skip, _stack, _key_decode, _string_decode) do
-    error(original, skip - 1)
+  defp error(<<_rest::bits>>, _original, skip, _stack, _key_decode, _string_decode) do
+    throw {:position, skip - 1}
   end
 
   defp empty_error(_original, skip) do
@@ -624,7 +624,7 @@ defmodule Jason.Decoder do
   end
 
   defp token_error(token, position, len) do
-    token_error(binary_part(token, position, len), position)
+    throw {:token, binary_part(token, position, len), position}
   end
 
   @compile {:inline, continue: 7}

lib/encode.ex

@@ -1,6 +1,8 @@
 defmodule Jason.EncodeError do
   defexception [:message]
 
+  @type t :: %__MODULE__{message: String.t}
+
   def exception(message) when is_binary(message) do
     %__MODULE__{message: message}
   end
@@ -28,6 +30,7 @@ defmodule Jason.Encode do
   # @compile :native
 
   @doc false
+  @spec encode(any, map) :: {:ok, iodata} | {:error, EncodeError.t}
   def encode(value, opts) do
     escape = escape_function(opts)
     encode_map = encode_map_function(opts)

lib/jason.ex

@@ -12,7 +12,7 @@ defmodule Jason do
 
   @type decode_opt :: {:keys, keys}
 
-  alias Jason.{Encode, Decoder, ParseError, EncodeError}
+  alias Jason.{Encode, Decoder, DecodeError, EncodeError}
 
   @doc """
   Parses a JSON value from `input` iodata.
@@ -40,7 +40,7 @@ defmodule Jason do
   Since the atoms are not garbage collected, this can pose a DoS attack vector when used
   on user-controlled data.
   """
-  @spec decode(iodata, [decode_opt]) :: {:ok, term} | {:error, ParseError.t()}
+  @spec decode(iodata, [decode_opt]) :: {:ok, term} | {:error, DecodeError.t()}
   def decode(input, opts \\ []) do
     input = IO.iodata_to_binary(input)
     Decoder.parse(input, format_decode_opts(opts))
@@ -117,7 +117,7 @@ defmodule Jason do
   writes and avoid allocating a continuous buffer for the whole
   resulting string, lowering memory use and increasing performance.
   """
-  @spec encode_to_iodata(term, [encode_opt]) :: {:ok, iodata} | {:error, Jason.EncodeError.t()}
+  @spec encode_to_iodata(term, [encode_opt]) :: {:ok, iodata} | {:error, EncodeError.t()}
   def encode_to_iodata(input, opts \\ []) do
     Encode.encode(input, format_encode_opts(opts))
   end

mix.exs

@@ -9,7 +9,8 @@ defmodule Jason.Mixfile do
       start_permanent: Mix.env() == :prod,
       consolidate_protocols: Mix.env != :test,
       deps: deps(),
-      aliases: aliases()
+      aliases: aliases(),
+      dialyzer: dialyzer()
     ]
   end
 
@@ -22,15 +23,16 @@ defmodule Jason.Mixfile do
   defp deps do
     [
       {:decimal, "~> 1.0", optional: true},
-      {:stream_data, "~> 0.4", obly: :test},
+      {:stream_data, "~> 0.4", only: :test},
       {:benchee, "~> 0.8", only: :dev},
       {:benchee_html, "~> 0.1", only: :dev},
       {:poison, "~> 3.0", only: :dev},
       {:exjsx, "~> 4.0", only: :dev},
       {:tiny, "~> 1.0", only: :dev},
       {:jsone, "~> 1.4", only: :dev},
       {:jiffy, "~> 0.14",  only: :dev},
-      {:json, "~> 1.0", only: :dev}
+      {:json, "~> 1.0", only: :dev},
+      {:dialyxir, "~> 0.5", only: :dev, runtime: false}
     ]
   end
 
@@ -40,4 +42,11 @@ defmodule Jason.Mixfile do
       "bench.decode": ["run bench/decode.exs"]
     ]
   end
+
+  defp dialyzer() do
+    [
+      plt_apps: [:kernel, :stdlib, :elixir, :decimal],
+      ignore_warnings: "dialyzer.ignore"
+    ]
+  end
 end

mix.lock

@@ -4,6 +4,7 @@
   "benchee_json": {:hex, :benchee_json, "0.4.0", "59d3277829bd1dca8373cdb20b916cb435c2647be235d09963fc0959db908c36", [:mix], [{:benchee, "~> 0.10", [hex: :benchee, repo: "hexpm", optional: false]}, {:poison, ">= 1.4.0", [hex: :poison, repo: "hexpm", optional: false]}], "hexpm"},
   "decimal": {:hex, :decimal, "1.4.1", "ad9e501edf7322f122f7fc151cce7c2a0c9ada96f2b0155b8a09a795c2029770", [:mix], [], "hexpm"},
   "deep_merge": {:hex, :deep_merge, "0.1.1", "c27866a7524a337b6a039eeb8dd4f17d458fd40fbbcb8c54661b71a22fffe846", [:mix], [], "hexpm"},
+  "dialyxir": {:hex, :dialyxir, "0.5.1", "b331b091720fd93e878137add264bac4f644e1ddae07a70bf7062c7862c4b952", [], [], "hexpm"},
   "elixir_make": {:hex, :elixir_make, "0.4.0", "992f38fabe705bb45821a728f20914c554b276838433349d4f2341f7a687cddf", [:mix], [], "hexpm"},
   "exjsx": {:hex, :exjsx, "4.0.0", "60548841e0212df401e38e63c0078ec57b33e7ea49b032c796ccad8cde794b5c", [:mix], [{:jsx, "~> 2.8.0", [hex: :jsx, repo: "hexpm", optional: false]}], "hexpm"},
   "jiffy": {:hex, :jiffy, "0.14.11", "919a87d491c5a6b5e3bbc27fafedc3a0761ca0b4c405394f121f582fd4e3f0e5", [:rebar3], [], "hexpm"},