HLint vs PMD

HLint is free software for analyzing Haskell source and suggesting possible improvements. It can point out alternative functions, simpler expressions, and redundant code. Every hint identifies the file and line, gives a severity and description, shows the code found, and proposes a replacement. Projects can configure behavior in a .hlint.yaml file, adding custom hints or ignoring selected suggestions. The --refactor flag applies some recommendations and requires the refactor executable from the apply-refact package on PATH. The --report flag creates an interactive HTML findings report. HLint runs on Linux, macOS, and Windows, with listed integrations including editor plugins, Haskell Language Server, ghc-mod, Intero, a GHC source plugin, Code Climate, and GitHub Actions. It analyzes one module at a time without type or scope knowledge. Version 3.10 is listed as released February 2, 2024. It is distributed under a BSD-style license.

PMD is a free, extensible static code analyzer that checks source code for programming flaws such as unused variables, empty catch blocks, and unnecessary object creation. It includes more than 400 built-in rules, and teams can write custom rules in Java or XPath. Its bundled CPD tool finds duplicated code across many programming languages. PMD checks source directories from the command line and can run as a Maven, Ant, Gradle, or bld build operation. Supported languages include Java, JavaScript, Salesforce Apex and Visualforce, Kotlin, Swift, Modelica, PL/SQL, Apache Velocity, JSP, WSDL, Maven POM, HTML, XML, and XSL; Scala is supported without Scala rules. It runs on Linux, macOS, and Windows and requires Java 8 or above. For CI, its GitHub Action can create SARIF reports and fail builds based on violation counts; documentation also covers GitLab, Jenkins, and Bamboo integrations. IDE integrations include Eclipse, IntelliJ IDEA, and Visual Studio Code, though some listed plugins are not actively maintained. Only the latest major version is actively developed.