Run dialyzer checks as GitHub Action

.github/workflows/dialyzer.yml

@@ -0,0 +1,46 @@
+name: Dialyzer
+
+on: [push, pull_request]
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: setup
+      uses: actions/setup-elixir@v1
+      with:
+        elixir-version: 1.11.2
+        otp-version: 23.0
+
+    - name: mix-cache
+      uses: actions/cache@v1
+      id: mix-cache
+      with:
+        path: deps
+        key: ${{ runner.os }}-mix-${{ hashFiles(format('{0}{1}', github.workspace, '/mix.lock')) }}
+
+    - name: mix-deps
+      if: steps.mix-cache.outputs.cache-hit != 'true'
+      run: |
+        mix local.rebar --force
+        mix local.hex --force
+        mix deps.get
+
+    - name: plt-cache
+      uses: actions/cache@v1
+      id: plt-cache
+      with:
+        path: plts
+        key: ${{ runner.os }}-plts-${{ hashFiles(format('{0}{1}', github.workspace, '/mix.lock')) }}
+
+    - name: plt-create
+      if: steps.plt-cache.outputs.cache-hit != 'true'
+      run: |
+        mkdir -p plts
+        mix dialyzer --plt
+
+    - name: dialyzer
+      run: mix dialyzer --no-check

.gitignore

@@ -1,4 +1,5 @@
 _build/
 deps/
 doc/
+plts/
 test/tmp/

mix.exs

@@ -61,7 +61,9 @@ defmodule Instream.MixProject do
         :race_conditions,
         :underspecs,
         :unmatched_returns
-      ]
+      ],
+      plt_core_path: "plts",
+      plt_file: {:no_warn, "plts/dialyzer.plt"}
     ]
   end