Implement HLint static code analysis integration

Co-authored-by: yegor256 <[email protected]>

Author: Copilot

.github/workflows/hlint.yml

@@ -0,0 +1,26 @@
+# SPDX-FileCopyrightText: Copyright (c) 2025 Objectionary.com
+# SPDX-License-Identifier: MIT
+---
+# yamllint disable rule:line-length
+name: hlint
+'on':
+  pull_request:
+    branches:
+      - master
+  push:
+    branches:
+      - master
+jobs:
+  hlint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up HLint
+        uses: haskell-actions/hlint-setup@v2
+        with:
+          version: '3.5'
+      - name: Run HLint
+        uses: haskell-actions/hlint-run@v2
+        with:
+          path: '["src/", "app/", "test/"]'
+          fail-on: warning

.hlint.yaml

@@ -0,0 +1,27 @@
+# HLint configuration file for phino
+# SPDX-FileCopyrightText: Copyright (c) 2025 Objectionary.com
+# SPDX-License-Identifier: MIT
+
+# Configuration for the phino Haskell project
+# See https://github.com/ndmitchell/hlint for documentation
+
+# Enable some additional checks
+- group: {name: default, enabled: true}
+
+# Disable some suggestions that might be too pedantic for this project
+- ignore: {name: "Use newtype instead of data"}
+- ignore: {name: "Use camelCase"}
+
+# Enable warnings for redundant imports, spacing, etc.
+- warn: {name: "Redundant do"}
+- warn: {name: "Redundant bracket"}
+- warn: {name: "Redundant $"}
+- warn: {name: "Use concatMap"}
+- warn: {name: "Use map"}
+- warn: {name: "Use fmap"}
+
+# Specify modules to check
+- modules:
+  - {name: [Prelude], within: []}
+
+# Custom rules for this project can be added here

phino.cabal

@@ -45,7 +45,7 @@ library
     Paths_phino
   build-depends:
     file-embed ^>=0.0.16.0,
-    base >= 4.18.3.0,
+    base ^>=4.18.3.0,
     containers,
     megaparsec >= 9.0,
     text,
@@ -93,6 +93,7 @@ test-suite spec
     YamlSpec,
     MiscSpec,
     XMIRSpec,
+    HLintSpec,
     Paths_phino
   autogen-modules:
     Paths_phino
@@ -114,6 +115,7 @@ test-suite spec
     text,
     silently,
     directory,
+    process,
     xml-conduit ^>=1.10
   build-tool-depends:
     hspec-discover:hspec-discover

test/HLintSpec.hs

@@ -0,0 +1,47 @@
+{-# LANGUAGE ScopedTypeVariables #-}
+-- SPDX-FileCopyrightText: Copyright (c) 2025 Objectionary.com
+-- SPDX-License-Identifier: MIT
+
+module HLintSpec (spec) where
+
+import Control.Exception (try, IOException)
+import System.Exit (ExitCode(..))
+import System.Process (readProcessWithExitCode)
+import Test.Hspec
+
+-- | Check if hlint is available on the system
+isHLintAvailable :: IO Bool
+isHLintAvailable = do
+  result <- try (readProcessWithExitCode "hlint" ["--version"] "")
+  case result of
+    Left (_ :: IOException) -> return False
+    Right (ExitSuccess, _, _) -> return True
+    Right (ExitFailure _, _, _) -> return False
+
+-- | Run hlint on a directory and check for success
+runHLintCheck :: String -> IO ()
+runHLintCheck dir = do
+  available <- isHLintAvailable
+  if not available 
+    then pendingWith "hlint is not available on this system"
+    else do
+      (exitCode, stdout, stderr) <- readProcessWithExitCode "hlint" [dir] ""
+      case exitCode of
+        ExitSuccess -> return ()
+        ExitFailure _ -> do
+          putStrLn $ "HLint warnings/errors in " ++ dir ++ ":"
+          putStrLn stdout
+          putStrLn stderr
+          exitCode `shouldBe` ExitSuccess
+
+spec :: Spec
+spec = do
+  describe "HLint" $ do
+    it "should pass hlint check for src/" $ do
+      runHLintCheck "src/"
+
+    it "should pass hlint check for app/" $ do
+      runHLintCheck "app/"
+          
+    it "should pass hlint check for test/" $ do
+      runHLintCheck "test/"