Merge branch 'e-kwsm-tautologically-false'

Tighten SC2333/SC2334 to only trigger against literals.
Merge branch 'tautologically-false' of github.com:e-kwsm/shellcheck into e-kwsm-tautologically-false
2025-07-06 04:51:37 -07:00 · 2025-05-17 00:56:52 +00:00 · 2025-05-17 00:55:50 +00:00 · 2025-05-12 17:04:34 +00:00 · 2025-04-27 16:16:49 -07:00 · 2025-04-27 16:09:19 -07:00
53 changed files with 1618 additions and 624 deletions
--- a/.github/ISSUE_TEMPLATE.md
+++ b/.github/ISSUE_TEMPLATE.md
@ -1,6 +1,6 @@
 #### For bugs
- Rule Id (if any, e.g. SC1000): 
- My shellcheck version (`shellcheck --version` or "online"): 
+- Rule Id (if any, e.g. SC1000):
+- My shellcheck version (`shellcheck --version` or "online"):
 - [ ] The rule's wiki page does not already cover this (e.g. https://shellcheck.net/wiki/SC2086)
 - [ ] I tried on https://www.shellcheck.net/ and verified that this is still a problem on the latest commit

--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@ -0,0 +1,7 @@
+version: 2
+
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@ -15,7 +15,7 @@ jobs:
          sudo apt-get install cabal-install

      - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
        with:
          fetch-depth: 0

@ -37,24 +37,47 @@ jobs:
          mv dist-newstyle/sdist/*.tar.gz source/source.tar.gz

      - name: Upload artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
        with:
          name: source
          path: source/

+  run_tests:
+    name: Run tests
+    needs: package_source
+    runs-on: ubuntu-latest
+    steps:
+      - name: Download artifacts
+        uses: actions/download-artifact@v4
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update && sudo apt-get install ghc cabal-install
+          cabal update
+
+      - name: Unpack source
+        run: |
+          cd source
+          tar xvf source.tar.gz --strip-components=1
+
+      - name: Build and run tests
+        run: |
+          cd source
+          cabal test
+
  build_source:
-    name: Build Source Code
+    name: Build
    needs: package_source
    strategy:
      matrix:
-        build: [linux.x86_64, linux.aarch64, linux.armv6hf, darwin.x86_64, windows.x86_64]
+        build: [linux.x86_64, linux.aarch64, linux.armv6hf, linux.riscv64, darwin.x86_64, darwin.aarch64, windows.x86_64]
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4

      - name: Download artifacts
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4

      - name: Build source
        run: |
@ -63,9 +86,9 @@ jobs:
          ( cd bin && ../build/run_builder ../source/source.tar.gz ../build/${{matrix.build}} )

      - name: Upload artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
        with:
-          name: bin
+          name: ${{matrix.build}}.bin
          path: bin/

  package_binary:
@ -74,25 +97,25 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4

      - name: Download artifacts
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4

      - name: Work around GitHub permissions bug
-        run: chmod +x bin/*/shellcheck*
+        run: chmod +x *.bin/*/shellcheck*

      - name: Package binaries
        run: |
          export TAGS="$(cat source/tags)"
          mkdir -p deploy
-          cp -r bin/* deploy
+          cp -r *.bin/* deploy
          cd deploy
          ../.prepare_deploy
          rm -rf */ README* LICENSE*

      - name: Upload artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
        with:
          name: deploy
          path: deploy/
@ -103,11 +126,16 @@ jobs:
    runs-on: ubuntu-latest
    environment: Deploy
    steps:
+      - name: Install Dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install hub
+
      - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4

      - name: Download artifacts
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4

      - name: Upload to GitHub
        env:
--- a/.gitignore
+++ b/.gitignore
@ -20,3 +20,4 @@ cabal.config
 /parts/
 /prime/
 *.snap
+/dist-newstyle/
--- a/.multi_arch_docker
+++ b/.multi_arch_docker
@ -3,28 +3,10 @@
 # binaries previously built and deployed to GitHub.

 function multi_arch_docker::install_docker_buildx() {
-  # Install up-to-date version of docker, with buildx support.
-  local -r docker_apt_repo='https://download.docker.com/linux/ubuntu'
-  curl -fsSL "${docker_apt_repo}/gpg" | sudo apt-key add -
-  local -r os="$(lsb_release -cs)"
-  sudo add-apt-repository "deb [arch=amd64] $docker_apt_repo $os stable"
-  sudo apt-get update
-  sudo apt-get -y -o Dpkg::Options::="--force-confnew" install docker-ce
-
-  # Enable docker daemon experimental support (for 'pull --platform').
-  local -r config='/etc/docker/daemon.json'
-  if [[ -e "$config" ]]; then
-    sudo sed -i -e 's/{/{ "experimental": true, /' "$config"
-  else
-    echo '{ "experimental": true }' | sudo tee "$config"
-  fi
-  sudo systemctl restart docker
-
  # Install QEMU multi-architecture support for docker buildx.
  docker run --rm --privileged multiarch/qemu-user-static --reset -p yes

  # Instantiate docker buildx builder with multi-architecture support.
-  export DOCKER_CLI_EXPERIMENTAL=enabled
  docker buildx create --name mybuilder
  docker buildx use mybuilder
  # Start up buildx and verify that all is OK.
@ -98,6 +80,7 @@ function multi_arch_docker::main() {
  export DOCKER_PLATFORMS='linux/amd64'
  DOCKER_PLATFORMS+=' linux/arm64'
  DOCKER_PLATFORMS+=' linux/arm/v6'
+  DOCKER_PLATFORMS+=' linux/riscv64'

  multi_arch_docker::install_docker_buildx
  multi_arch_docker::login_to_docker_hub
--- a/.snapsquid.conf
+++ b/.snapsquid.conf
@ -1,14 +0,0 @@
-# In 2015, cabal-install had a http bug triggered when proxies didn't keep
-# the connection open. This version made it into Ubuntu Xenial as used by
-# Snapcraft. In June 2018, Snapcraft's proxy started triggering this bug.
-#
-#     https://bugs.launchpad.net/launchpad-buildd/+bug/1797809
-#
-# Workaround: add more proxy
-
-visible_hostname localhost
-http_port 8888
-cache_peer 10.10.10.1 parent 8222 0 no-query default
-cache_peer_domain localhost !.internal
-http_access allow all
-
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -1,3 +1,47 @@
+## Git
+### Added
+- SC2327/SC2328: Warn about capturing the output of redirected commands.
+- SC2329: Warn when (non-escaping) functions are never invoked.
+- SC2330: Warn about unsupported glob matches with [[ .. ]] in BusyBox.
+- SC2331: Suggest using standard -e instead of unary -a in tests.
+- SC2332: Warn about `[ ! -o opt ]` being unconditionally true in Bash.
+- SC3062: Warn about bashism `[ -o opt ]`.
+- Precompiled binaries for Linux riscv64 (linux.riscv64)
+### Changed
+- SC2002 about Useless Use Of Cat is now disabled by default. It can be
+  re-enabled with `--enable=useless-use-of-cat` or equivalent directive.
+- SC2015 about `A && B || C` no longer triggers when B is a test command.
+- SC3012: Do not warn about `\<` and `\>` in test/[] as specified in POSIX.1-2024
+### Fixed
+- SC2218 about function use-before-define is now more accurate.
+- SC2317 about unreachable commands is now less spammy for nested ones.
+- SC2292, optional suggestion for [[ ]], now triggers for Busybox.
+
+### Removed
+- SC3013: removed since the operators `-ot/-nt/-ef` are specified in POSIX.1-2024
+
+## v0.10.0 - 2024-03-07
+### Added
+- Precompiled binaries for macOS ARM64 (darwin.aarch64)
+- Added support for busybox sh
+- Added flag --rcfile to specify an rc file by name.
+- Added `extended-analysis=true` directive to enable/disable dataflow analysis
+  (with a corresponding --extended-analysis flag).
+- SC2324: Warn when x+=1 appends instead of increments
+- SC2325: Warn about multiple `!`s in dash/sh.
+- SC2326: Warn about `foo | ! bar` in bash/dash/sh.
+- SC3012: Warn about lexicographic-compare bashism in test like in [ ]
+- SC3013: Warn bashism `test _ -op/-nt/-ef _` like in [ ]
+- SC3014: Warn bashism `test _ == _` like in [ ]
+- SC3015: Warn bashism `test _ =~ _` like in [ ]
+- SC3016: Warn bashism `test -v _` like in [ ]
+- SC3017: Warn bashism `test -a _` like in [ ]
+
+### Fixed
+- source statements with here docs now work correctly
+- "(Array.!): undefined array element" error should no longer occur
+
+
 ## v0.9.0 - 2022-12-12
 ### Added
 - SC2316: Warn about 'local readonly foo' and similar (thanks, patrickxia!)
--- a/README.md
+++ b/README.md
@ -77,7 +77,7 @@ You can see ShellCheck suggestions directly in a variety of editors.

 * Sublime, through [SublimeLinter](https://github.com/SublimeLinter/SublimeLinter-shellcheck).

-* Atom, through [Linter](https://github.com/AtomLinter/linter-shellcheck).
+* Pulsar Edit (former Atom), through [linter-shellcheck-pulsar](https://github.com/pulsar-cooperative/linter-shellcheck-pulsar).

 * VSCode, through [vscode-shellcheck](https://github.com/timonwong/vscode-shellcheck).

@ -110,8 +110,11 @@ Services and platforms that have ShellCheck pre-installed and ready to use:
 * [Codacy](https://www.codacy.com/)
 * [Code Climate](https://codeclimate.com/)
 * [Code Factor](https://www.codefactor.io/)
+* [Codety](https://www.codety.io/) via the [Codety Scanner](https://github.com/codetyio/codety-scanner)
 * [CircleCI](https://circleci.com) via the [ShellCheck Orb](https://circleci.com/orbs/registry/orb/circleci/shellcheck)
 * [Github](https://github.com/features/actions) (only Linux)
+* [Trunk Check](https://trunk.io/products/check) (universal linter; [allows you to explicitly version your shellcheck install](https://github.com/trunk-io/plugins/blob/bcbb361dcdbe4619af51ea7db474d7fb87540d20/.trunk/trunk.yaml#L32)) via the [shellcheck plugin](https://github.com/trunk-io/plugins/blob/main/linters/shellcheck/plugin.yaml)
+* [CodeRabbit](https://coderabbit.ai/)

 Most other services, including [GitLab](https://about.gitlab.com/), let you install
 ShellCheck yourself, either through the system's package manager (see [Installing](#installing)),
@ -193,6 +196,12 @@ On Windows (via [chocolatey](https://chocolatey.org/packages/shellcheck)):
 C:\> choco install shellcheck
 ```

+Or Windows (via [winget](https://github.com/microsoft/winget-pkgs)):
+
+```cmd
+C:\> winget install --id koalaman.shellcheck
+```
+
 Or Windows (via [scoop](http://scoop.sh)):

 ```cmd
@ -221,17 +230,26 @@ Using the [nix package manager](https://nixos.org/nix):
 nix-env -iA nixpkgs.shellcheck
 ```

+Using the [Flox package manager](https://flox.dev/)
+```sh
+flox install shellcheck
+```
+
 Alternatively, you can download pre-compiled binaries for the latest release here:

 * [Linux, x86_64](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.linux.x86_64.tar.xz) (statically linked)
 * [Linux, armv6hf](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.linux.armv6hf.tar.xz), i.e. Raspberry Pi (statically linked)
 * [Linux, aarch64](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.linux.aarch64.tar.xz) aka ARM64 (statically linked)
+* [macOS, aarch64](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.darwin.aarch64.tar.xz)
 * [macOS, x86_64](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.darwin.x86_64.tar.xz)
 * [Windows, x86](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.zip)

 or see the [GitHub Releases](https://github.com/koalaman/shellcheck/releases) for other releases
 (including the [latest](https://github.com/koalaman/shellcheck/releases/tag/latest) meta-release for daily git builds).

+There are currently no official binaries for Apple Silicon, but third party builds are available via
+[ShellCheck for Visual Studio Code](https://github.com/vscode-shellcheck/shellcheck-binaries/releases).
+
 Distro packages already come with a `man` page. If you are building from source, it can be installed with:

 ```console
@ -299,10 +317,6 @@ Verify that `cabal` is installed and update its dependency list with

    $ cabal install

-Or if you intend to run the tests:
-
-    $ cabal install --enable-tests
-
 This will compile ShellCheck and install it to your `~/.cabal/bin` directory.

 Add this directory to your `PATH` (for bash, add this to your `~/.bashrc`):
@ -548,4 +562,3 @@ Happy ShellChecking!

 * The wiki has [long form descriptions](https://github.com/koalaman/shellcheck/wiki/Checks) for each warning, e.g. [SC2221](https://github.com/koalaman/shellcheck/wiki/SC2221).
 * ShellCheck does not attempt to enforce any kind of formatting or indenting style, so also check out [shfmt](https://github.com/mvdan/sh)!
-
--- a/ShellCheck.cabal
+++ b/ShellCheck.cabal
@ -1,5 +1,5 @@
 Name:             ShellCheck
-Version:          0.9.0
+Version:          0.10.0
 Synopsis:         Shell script analysis tool
 License:          GPL-3
 License-file:     LICENSE
@ -46,21 +46,21 @@ library
        semigroups
    build-depends:
      -- The lower bounds are based on GHC 7.10.3
-      -- The upper bounds are based on GHC 9.4.3
-      aeson                >= 1.4.0 && < 2.2,
+      -- The upper bounds are based on GHC 9.8.1
+      aeson                >= 1.4.0 && < 2.3,
      array                >= 0.5.1 && < 0.6,
      base                 >= 4.8.0.0 && < 5,
-      bytestring           >= 0.10.6 && < 0.12,
-      containers           >= 0.5.6 && < 0.7,
-      deepseq              >= 1.4.1 && < 1.5,
-      Diff                 >= 0.4.0 && < 0.5,
-      fgl                  >= 5.7.0 && < 5.9,
-      filepath             >= 1.4.0 && < 1.5,
-      mtl                  >= 2.2.2 && < 2.3,
+      bytestring           >= 0.10.6 && < 0.13,
+      containers           >= 0.5.6 && < 0.8,
+      deepseq              >= 1.4.1 && < 1.6,
+      Diff                 >= 0.4.0 && < 1.1,
+      fgl                  (>= 5.7.0 && < 5.8.1.0) || (>= 5.8.1.1 && < 5.9),
+      filepath             >= 1.4.0 && < 1.6,
+      mtl                  >= 2.2.2 && < 2.4,
      parsec               >= 3.1.14 && < 3.2,
-      QuickCheck           >= 2.14.2 && < 2.15,
+      QuickCheck           >= 2.14.2 && < 2.16,
      regex-tdfa           >= 1.2.0 && < 1.4,
-      transformers         >= 0.4.2 && < 0.6,
+      transformers         >= 0.4.2 && < 0.7,

      -- getXdgDirectory from 1.2.3.0
      directory            >= 1.2.3 && < 1.4,
--- a/build/README.md
+++ b/build/README.md
@ -11,3 +11,7 @@ This makes it simple to build any release without exotic hardware or software.

 An image can be built and tagged using `build_builder`,
 and run on a source tarball using `run_builder`.
+
+Tip: Are you developing an image that relies on QEmu usermode emulation?
+     It's easy to accidentally depend on binfmt\_misc on the host OS.
+     Do a `echo 0 | sudo tee /proc/sys/fs/binfmt_misc/status` before testing.
--- a/build/darwin.aarch64/Dockerfile
+++ b/build/darwin.aarch64/Dockerfile
@ -0,0 +1,40 @@
+FROM ghcr.io/shepherdjerred/macos-cross-compiler:latest
+
+ENV TARGET aarch64-apple-darwin22
+ENV TARGETNAME darwin.aarch64
+
+# Build dependencies
+USER root
+ENV DEBIAN_FRONTEND noninteractive
+ENV LC_ALL C.utf8
+
+# Install basic deps
+RUN apt-get update && apt-get install -y automake autoconf build-essential curl xz-utils qemu-user-static
+
+# Install a more suitable host compiler
+WORKDIR /host-ghc
+RUN curl -L "https://downloads.haskell.org/~cabal/cabal-install-3.9.0.0/cabal-install-3.9-x86_64-linux-alpine.tar.xz" | tar xJv -C /usr/local/bin
+RUN curl -L 'https://downloads.haskell.org/~ghc/8.10.7/ghc-8.10.7-x86_64-deb10-linux.tar.xz' | tar xJ --strip-components=1
+RUN ./configure && make install
+
+# Build GHC. We have to use an old version because cross-compilation across OS has since broken.
+WORKDIR /ghc
+RUN curl -L "https://downloads.haskell.org/~ghc/8.10.7/ghc-8.10.7-src.tar.xz" | tar xJ --strip-components=1
+RUN apt-get install -y llvm-12
+RUN ./boot && ./configure --host x86_64-linux-gnu --build x86_64-linux-gnu --target "$TARGET"
+RUN cp mk/flavours/quick-cross.mk mk/build.mk && make -j "$(nproc)"
+RUN make install
+
+# Due to an apparent cabal bug, we specify our options directly to cabal
+# It won't reuse caches if ghc-options are specified in ~/.cabal/config
+ENV CABALOPTS "--ghc-options;-optc-Os -optc-fPIC;--with-ghc=$TARGET-ghc;--with-hc-pkg=$TARGET-ghc-pkg;--constraint=hashable==1.3.5.0"
+
+# Prebuild the dependencies
+RUN cabal update
+RUN IFS=';' && cabal install --dependencies-only $CABALOPTS ShellCheck
+
+# Copy the build script
+COPY build /usr/bin
+
+WORKDIR /scratch
+ENTRYPOINT ["/usr/bin/build"]
--- a/build/darwin.aarch64/build
+++ b/build/darwin.aarch64/build
@ -0,0 +1,16 @@
+#!/bin/sh
+set -xe
+{
+  tar xzv --strip-components=1
+  chmod +x striptests && ./striptests
+  mkdir "$TARGETNAME"
+  ( IFS=';'; cabal build $CABALOPTS )
+  find . -name shellcheck -type f -exec mv {} "$TARGETNAME/" \;
+  ls -l "$TARGETNAME"
+  # Stripping invalidates the code signature and the build image does
+  # not appear to have anything similar to the 'codesign' tool.
+  # "$TARGET-strip" "$TARGETNAME/shellcheck"
+  ls -l "$TARGETNAME"
+  file "$TARGETNAME/shellcheck" | grep "Mach-O 64-bit arm64 executable"
+} >&2
+tar czv "$TARGETNAME"
--- a/build/darwin.aarch64/tag
+++ b/build/darwin.aarch64/tag
@ -0,0 +1 @@
+koalaman/scbuilder-darwin-aarch64
--- a/build/darwin.x86_64/Dockerfile
+++ b/build/darwin.x86_64/Dockerfile
@ -6,15 +6,18 @@ ENV TARGETNAME darwin.x86_64
 # Build dependencies
 USER root
 ENV DEBIAN_FRONTEND noninteractive
-RUN apt-get update && apt-get install -y ghc automake autoconf llvm curl
+RUN sed -e 's/focal/kinetic/g' -i /etc/apt/sources.list
+RUN apt-get update
+RUN apt-get dist-upgrade -y
+RUN apt-get install -y ghc automake autoconf llvm curl alex happy

 # Build GHC
 WORKDIR /ghc
-RUN curl -L "https://downloads.haskell.org/~ghc/8.10.4/ghc-8.10.4-src.tar.xz" | tar xJ --strip-components=1
-RUN ./boot && ./configure --host x86_64-linux-gnu --build x86_64-linux-gnu --target "$TARGET"
+RUN curl -L "https://downloads.haskell.org/~ghc/9.2.5/ghc-9.2.5-src.tar.xz" | tar xJ --strip-components=1
+RUN ./configure --host x86_64-linux-gnu --build x86_64-linux-gnu --target "$TARGET"
 RUN cp mk/flavours/quick-cross.mk mk/build.mk && make -j "$(nproc)"
 RUN make install
-RUN curl -L "https://downloads.haskell.org/~cabal/cabal-install-3.2.0.0/cabal-install-3.2.0.0-x86_64-unknown-linux.tar.xz" | tar xJv -C /usr/local/bin
+RUN curl -L "https://downloads.haskell.org/~cabal/cabal-install-3.9.0.0/cabal-install-3.9-x86_64-linux-alpine.tar.xz" | tar xJv -C /usr/local/bin

 # Due to an apparent cabal bug, we specify our options directly to cabal
 # It won't reuse caches if ghc-options are specified in ~/.cabal/config
--- a/build/darwin.x86_64/build
+++ b/build/darwin.x86_64/build
@ -4,7 +4,6 @@ set -xe
  tar xzv --strip-components=1
  chmod +x striptests && ./striptests
  mkdir "$TARGETNAME"
-  cabal update
  ( IFS=';'; cabal build $CABALOPTS )
  find . -name shellcheck -type f -exec mv {} "$TARGETNAME/" \;
  ls -l "$TARGETNAME"
--- a/build/linux.aarch64/Dockerfile
+++ b/build/linux.aarch64/Dockerfile
@ -6,19 +6,29 @@ ENV TARGETNAME linux.aarch64
 # Build dependencies
 USER root
 ENV DEBIAN_FRONTEND noninteractive
-RUN apt-get update && apt-get install -y ghc automake autoconf build-essential llvm curl qemu-user-static gcc-$TARGET
+
+# These deps are from 20.04, because GHC's compiler/llvm support moves slowly
+RUN apt-get update && apt-get install -y llvm gcc-$TARGET
+
+# The rest are from 22.10
+RUN sed -e 's/focal/kinetic/g' -i /etc/apt/sources.list
+# Kinetic does not receive updates anymore, switch to last available
+RUN sed -e 's/archive.ubuntu.com/old-releases.ubuntu.com/g' -i /etc/apt/sources.list
+RUN sed -e 's/security.ubuntu.com/old-releases.ubuntu.com/g' -i /etc/apt/sources.list
+
+RUN apt-get update && apt-get install -y ghc alex happy automake autoconf build-essential curl qemu-user-static

 # Build GHC
 WORKDIR /ghc
-RUN curl -L "https://downloads.haskell.org/~ghc/8.10.4/ghc-8.10.4-src.tar.xz" | tar xJ --strip-components=1
+RUN curl -L "https://downloads.haskell.org/~ghc/9.2.8/ghc-9.2.8-src.tar.xz" | tar xJ --strip-components=1
 RUN ./boot && ./configure --host x86_64-linux-gnu --build x86_64-linux-gnu --target "$TARGET"
 RUN cp mk/flavours/quick-cross.mk mk/build.mk && make -j "$(nproc)"
 RUN make install
-RUN curl -L "https://downloads.haskell.org/~cabal/cabal-install-3.2.0.0/cabal-install-3.2.0.0-x86_64-unknown-linux.tar.xz" | tar xJv -C /usr/local/bin
+RUN curl -L "https://downloads.haskell.org/~cabal/cabal-install-3.9.0.0/cabal-install-3.9-x86_64-linux-alpine.tar.xz" | tar xJv -C /usr/local/bin

 # Due to an apparent cabal bug, we specify our options directly to cabal
 # It won't reuse caches if ghc-options are specified in ~/.cabal/config
-ENV CABALOPTS "--ghc-options;-split-sections -optc-Os -optc-Wl,--gc-sections;--with-ghc=$TARGET-ghc;--with-hc-pkg=$TARGET-ghc-pkg"
+ENV CABALOPTS "--ghc-options;-split-sections -optc-Os -optc-Wl,--gc-sections -optc-fPIC;--with-ghc=$TARGET-ghc;--with-hc-pkg=$TARGET-ghc-pkg;-c;hashable -arch-native"

 # Prebuild the dependencies
 RUN cabal update && IFS=';' && cabal install --dependencies-only $CABALOPTS ShellCheck
--- a/build/linux.aarch64/build
+++ b/build/linux.aarch64/build
@ -4,7 +4,6 @@ set -xe
  tar xzv --strip-components=1
  chmod +x striptests && ./striptests
  mkdir "$TARGETNAME"
-  cabal update
  ( IFS=';'; cabal build $CABALOPTS --enable-executable-static )
  find . -name shellcheck -type f -exec mv {} "$TARGETNAME/" \;
  ls -l "$TARGETNAME"
--- a/build/linux.armv6hf/Dockerfile
+++ b/build/linux.armv6hf/Dockerfile
@ -1,25 +1,7 @@
-# I've again spent days trying to get a working armv6hf compiler going.
-# God only knows how many recompilations of GCC, GHC, libraries, and
-# ShellCheck itself, has gone into it.
-#
-# I tried Debian's toolchain.  I tried my custom one built according to
-# RPi `gcc -v`. I tried GHC9, glibc, musl, registerised vs not, but
-# nothing has yielded an armv6hf binary that does not immediately
-# segfault on qemu-arm-static or the RPi itself.
-#
-# I then tried the same but with armv7hf. Same story.
-#
-# Emulating the entire userspace with balenalib again?  Very strange build
-# failures where programs would fail to execute with > ~100 arguments.
-#
-# Finally, creating our own appears to work when using a custom QEmu
-# patched to follow execve calls.
-#
-# PS: $100 bounty for getting a RPi1 compatible static build going
-#     with cross-compilation, similar to what the aarch64 build does.
-#
+# This Docker file uses a custom QEmu fork with patches to follow execve
+# to build all of ShellCheck emulated.

-FROM ubuntu:20.04
+FROM ubuntu:24.04

 ENV TARGETNAME linux.armv6hf

@ -27,34 +9,34 @@ ENV TARGETNAME linux.armv6hf
 USER root
 ENV DEBIAN_FRONTEND noninteractive
 RUN apt-get update
-RUN apt-get install -y build-essential git ninja-build python3 pkg-config libglib2.0-dev libpixman-1-dev
-WORKDIR /build
-RUN git clone --depth 1 https://github.com/koalaman/qemu
-RUN cd qemu && ./configure --static && cd build && ninja qemu-arm
-RUN cp qemu/build/qemu-arm /build/qemu-arm-static
+RUN apt-get install -y --no-install-recommends build-essential git ninja-build python3 pkg-config libglib2.0-dev libpixman-1-dev python3-setuptools ca-certificates debootstrap
+WORKDIR /qemu
+RUN git clone --depth 1 https://github.com/koalaman/qemu .
+RUN ./configure --static --disable-werror && cd build && ninja qemu-arm
 ENV QEMU_EXECVE 1

+# Convenience utility
+COPY scutil /bin/scutil
+COPY scutil /chroot/bin/scutil
+RUN chmod +x /bin/scutil /chroot/bin/scutil
+
 # Set up an armv6 userspace
 WORKDIR /
-RUN apt-get install -y debootstrap qemu-user-static
-# We expect this to fail if the host doesn't have binfmt qemu support
-RUN qemu-debootstrap --arch armhf bullseye pi http://mirrordirector.raspbian.org/raspbian || [ -e /pi/etc/issue ]
-RUN cp /build/qemu-arm-static /pi/usr/bin/qemu-arm-static
-RUN printf > /bin/pirun '%s\n' '#!/bin/sh' 'chroot /pi /usr/bin/qemu-arm-static /usr/bin/env "$@"' && chmod +x /bin/pirun
-# If the debootstrap process didn't finish, continue it
-RUN [ ! -e /pi/debootstrap ] || pirun '/debootstrap/debootstrap' --second-stage
+RUN debootstrap --arch armhf --variant=minbase --foreign bookworm /chroot http://mirrordirector.raspbian.org/raspbian
+RUN cp /qemu/build/qemu-arm /chroot/bin/qemu
+RUN scutil emu /debootstrap/debootstrap --second-stage

 # Install deps in the chroot
-RUN pirun apt-get update
-RUN pirun apt-get install -y ghc cabal-install
+RUN scutil emu apt-get update
+RUN scutil emu apt-get install -y --no-install-recommends ghc cabal-install
+RUN scutil emu cabal update

 # Finally we can build the current dependencies. This takes hours.
 ENV CABALOPTS "--ghc-options;-split-sections -optc-Os -optc-Wl,--gc-sections;--gcc-options;-Os -Wl,--gc-sections -ffunction-sections -fdata-sections"
-RUN pirun cabal update
-RUN IFS=";" && pirun cabal install --dependencies-only $CABALOPTS ShellCheck
-RUN IFS=';' && pirun cabal install $CABALOPTS --lib fgl
+# Generated with `cabal freeze --constraint 'hashable -arch-native'`
+COPY cabal.project.freeze /chroot/etc
+RUN IFS=";" && scutil install_from_freeze /chroot/etc/cabal.project.freeze emu cabal install $CABALOPTS

 # Copy the build script
-WORKDIR /pi/scratch
-COPY build /pi/usr/bin
-ENTRYPOINT ["/bin/pirun", "/usr/bin/build"]
+COPY build /chroot/bin
+ENTRYPOINT ["/bin/scutil", "emu", "/bin/build"]
--- a/build/linux.armv6hf/build
+++ b/build/linux.armv6hf/build
@ -1,8 +1,9 @@
 #!/bin/sh
 set -xe
-cd /scratch
+mkdir /scratch && cd /scratch
 {
  tar xzv --strip-components=1
+  cp /etc/cabal.project.freeze .
  chmod +x striptests && ./striptests
  mkdir "$TARGETNAME"
  # This script does not cabal update because compiling anything new is slow
--- a/build/linux.armv6hf/cabal.project.freeze
+++ b/build/linux.armv6hf/cabal.project.freeze
@ -0,0 +1,93 @@
+active-repositories: hackage.haskell.org:merge
+constraints: any.Diff ==0.5,
+             any.OneTuple ==0.4.2,
+             any.QuickCheck ==2.14.3,
+             QuickCheck -old-random +templatehaskell,
+             any.StateVar ==1.2.2,
+             any.aeson ==2.2.3.0,
+             aeson +ordered-keymap,
+             any.array ==0.5.4.0,
+             any.assoc ==1.1.1,
+             assoc -tagged,
+             any.base ==4.15.1.0,
+             any.base-orphans ==0.9.2,
+             any.bifunctors ==5.6.2,
+             bifunctors +tagged,
+             any.binary ==0.8.8.0,
+             any.bytestring ==0.10.12.1,
+             any.character-ps ==0.1,
+             any.comonad ==5.0.8,
+             comonad +containers +distributive +indexed-traversable,
+             any.containers ==0.6.4.1,
+             any.contravariant ==1.5.5,
+             contravariant +semigroups +statevar +tagged,
+             any.data-array-byte ==0.1.0.1,
+             any.data-fix ==0.3.3,
+             any.deepseq ==1.4.5.0,
+             any.directory ==1.3.6.2,
+             any.distributive ==0.6.2.1,
+             distributive +semigroups +tagged,
+             any.dlist ==1.0,
+             dlist -werror,
+             any.exceptions ==0.10.4,
+             any.fgl ==5.8.2.0,
+             fgl +containers042,
+             any.filepath ==1.4.2.1,
+             any.foldable1-classes-compat ==0.1,
+             foldable1-classes-compat +tagged,
+             any.generically ==0.1.1,
+             any.ghc-bignum ==1.1,
+             any.ghc-boot-th ==9.0.2,
+             any.ghc-prim ==0.7.0,
+             any.hashable ==1.4.6.0,
+             hashable -arch-native +integer-gmp -random-initial-seed,
+             any.indexed-traversable ==0.1.4,
+             any.indexed-traversable-instances ==0.1.2,
+             any.integer-conversion ==0.1.1,
+             any.integer-logarithms ==1.0.3.1,
+             integer-logarithms -check-bounds +integer-gmp,
+             any.mtl ==2.2.2,
+             any.network-uri ==2.6.4.2,
+             any.parsec ==3.1.14.0,
+             any.pretty ==1.1.3.6,
+             any.primitive ==0.9.0.0,
+             any.process ==1.6.13.2,
+             any.random ==1.2.1.2,
+             any.regex-base ==0.94.0.2,
+             any.regex-tdfa ==1.3.2.2,
+             regex-tdfa +doctest -force-o2,
+             any.rts ==1.0.2,
+             any.scientific ==0.3.8.0,
+             scientific -integer-simple,
+             any.semialign ==1.3.1,
+             semialign +semigroupoids,
+             any.semigroupoids ==6.0.1,
+             semigroupoids +comonad +containers +contravariant +distributive +tagged +unordered-containers,
+             any.splitmix ==0.1.0.5,
+             splitmix -optimised-mixer,
+             any.stm ==2.5.0.0,
+             any.strict ==0.5,
+             any.tagged ==0.8.8,
+             tagged +deepseq +transformers,
+             any.template-haskell ==2.17.0.0,
+             any.text ==1.2.5.0,
+             any.text-iso8601 ==0.1.1,
+             any.text-short ==0.1.6,
+             text-short -asserts,
+             any.th-abstraction ==0.7.0.0,
+             any.th-compat ==0.1.5,
+             any.these ==1.2.1,
+             any.time ==1.9.3,
+             any.time-compat ==1.9.7,
+             any.transformers ==0.5.6.2,
+             any.transformers-compat ==0.7.2,
+             transformers-compat -five +five-three -four +generic-deriving +mtl -three -two,
+             any.unix ==2.7.2.2,
+             any.unordered-containers ==0.2.20,
+             unordered-containers -debug,
+             any.uuid-types ==1.0.6,
+             any.vector ==0.13.1.0,
+             vector +boundschecks -internalchecks -unsafechecks -wall,
+             any.vector-stream ==0.1.0.1,
+             any.witherable ==0.5
+index-state: hackage.haskell.org 2024-06-18T02:21:19Z
--- a/build/linux.armv6hf/scutil
+++ b/build/linux.armv6hf/scutil
@ -0,0 +1,48 @@
+#!/bin/dash
+# Various ShellCheck build utility functions
+
+# Generally set a ulimit to avoid QEmu using too much memory
+ulimit -v "$((10*1024*1024))"
+# If we happen to invoke or run under QEmu, make sure to follow execve.
+# This requires a patched QEmu.
+export QEMU_EXECVE=1
+
+# Retry a command until it succeeds
+# Usage: scutil retry 3 mycmd
+retry() {
+  n="$1"
+  ret=1
+  shift
+  while [ "$n" -gt 0 ]
+  do
+    "$@"
+    ret=$?
+    [ "$ret" = 0 ] && break
+    n=$((n-1))
+  done
+  return "$ret"
+}
+
+# Install all dependencies from a freeze file
+# Usage: scutil install_from_freeze /path/cabal.project.freeze cabal install
+install_from_freeze() {
+  linefeed=$(printf '\nx')
+  linefeed=${linefeed%x}
+  flags=$(
+    sed 's/constraints:/&\n /' "$1" |
+    grep -vw -e rts -e base |
+    sed -n -e 's/^  *\([^,]*\).*/\1/p' |
+    sed -e 's/any\.\([^ ]*\) ==\(.*\)/\1-\2/; te; s/.*/--constraint\n&/; :e')
+  shift
+  # shellcheck disable=SC2086
+  ( IFS=$linefeed; set -x; "$@" $flags )
+}
+
+# Run a command under emulation.
+# This assumes the correct emulator is named 'qemu' and the chroot is /chroot
+# Usage: scutil emu echo "Hello World"
+emu() {
+  chroot /chroot /bin/qemu /usr/bin/env "$@"
+}
+
+"$@"
--- a/build/linux.riscv64/Dockerfile
+++ b/build/linux.riscv64/Dockerfile
@ -0,0 +1,46 @@
+FROM ubuntu:24.04
+
+ENV TARGETNAME linux.riscv64
+ENV TARGET riscv64-linux-gnu
+
+USER root
+ENV DEBIAN_FRONTEND noninteractive
+
+# Init base
+RUN apt-get update -y
+
+# Install qemu
+RUN apt-get install -y --no-install-recommends build-essential ninja-build python3 pkg-config libglib2.0-dev libpixman-1-dev curl ca-certificates python3-virtualenv git python3-setuptools debootstrap
+WORKDIR /qemu
+RUN git clone --depth 1 https://github.com/koalaman/qemu .
+RUN ./configure --target-list=riscv64-linux-user --static --disable-system --disable-pie --disable-werror
+RUN cd build && ninja qemu-riscv64
+ENV QEMU_EXECVE 1
+
+# Convenience utility
+COPY scutil /bin/scutil
+# We have to copy to /usr/bin because debootstrap will try to symlink /bin and fail if it exists
+COPY scutil /chroot/usr/bin/scutil
+RUN chmod +x /bin/scutil /chroot/usr/bin/scutil
+
+# Set up a riscv64 userspace
+WORKDIR /
+RUN debootstrap --arch=riscv64 --variant=minbase --components=main,universe --foreign noble /chroot http://ports.ubuntu.com/ubuntu-ports
+RUN cp /qemu/build/qemu-riscv64 /chroot/bin/qemu
+RUN scutil emu /debootstrap/debootstrap --second-stage
+
+# Install deps in the chroot
+RUN scutil emu apt-get update
+RUN scutil emu apt-get install -y --no-install-recommends ghc cabal-install
+RUN scutil emu cabal update
+
+# Generated with: cabal freeze -c 'hashable -arch-native'. We put it in /etc so cabal won't find it.
+COPY cabal.project.freeze /chroot/etc
+
+# Build all dependencies from the freeze file. The emulator segfaults at random,
+# so retry a few times.
+RUN scutil install_from_freeze /chroot/etc/cabal.project.freeze retry 5 emu cabal install --keep-going
+
+# Copy the build script
+COPY build /chroot/bin/build
+ENTRYPOINT ["/bin/scutil", "emu", "/bin/build"]
--- a/build/linux.riscv64/build
+++ b/build/linux.riscv64/build
@ -0,0 +1,21 @@
+#!/bin/sh
+set -xe
+IFS=';'
+{
+  mkdir -p /tmp/scratch
+  cd /tmp/scratch
+  tar xzv --strip-components=1
+  chmod +x striptests && ./striptests
+  # Use a freeze file to ensure we use the same dependencies we cached during
+  # the docker image build. We don't want to spend time compiling anything new.
+  cp /etc/cabal.project.freeze .
+  mkdir "$TARGETNAME"
+  # Retry in case of random segfault
+  scutil retry 3 cabal build --enable-executable-static
+  find . -name shellcheck -type f -exec mv {} "$TARGETNAME/" \;
+  ls -l "$TARGETNAME"
+  "$TARGET-strip" -s "$TARGETNAME/shellcheck"
+  ls -l "$TARGETNAME"
+  "$TARGETNAME/shellcheck" --version
+} >&2
+tar czv "$TARGETNAME"
--- a/build/linux.riscv64/cabal.project.freeze
+++ b/build/linux.riscv64/cabal.project.freeze
@ -0,0 +1,93 @@
+active-repositories: hackage.haskell.org:merge
+constraints: any.Diff ==0.5,
+             any.OneTuple ==0.4.2,
+             any.QuickCheck ==2.14.3,
+             QuickCheck -old-random +templatehaskell,
+             any.StateVar ==1.2.2,
+             any.aeson ==2.2.3.0,
+             aeson +ordered-keymap,
+             any.array ==0.5.4.0,
+             any.assoc ==1.1.1,
+             assoc -tagged,
+             any.base ==4.17.2.0,
+             any.base-orphans ==0.9.2,
+             any.bifunctors ==5.6.2,
+             bifunctors +tagged,
+             any.binary ==0.8.9.1,
+             any.bytestring ==0.11.5.2,
+             any.character-ps ==0.1,
+             any.comonad ==5.0.8,
+             comonad +containers +distributive +indexed-traversable,
+             any.containers ==0.6.7,
+             any.contravariant ==1.5.5,
+             contravariant +semigroups +statevar +tagged,
+             any.data-fix ==0.3.3,
+             any.deepseq ==1.4.8.0,
+             any.directory ==1.3.7.1,
+             any.distributive ==0.6.2.1,
+             distributive +semigroups +tagged,
+             any.dlist ==1.0,
+             dlist -werror,
+             any.exceptions ==0.10.5,
+             any.fgl ==5.8.2.0,
+             fgl +containers042,
+             any.filepath ==1.4.2.2,
+             any.foldable1-classes-compat ==0.1,
+             foldable1-classes-compat +tagged,
+             any.generically ==0.1.1,
+             any.ghc-bignum ==1.3,
+             any.ghc-boot-th ==9.4.7,
+             any.ghc-prim ==0.9.1,
+             any.hashable ==1.4.6.0,
+             hashable -arch-native +integer-gmp -random-initial-seed,
+             any.indexed-traversable ==0.1.4,
+             any.indexed-traversable-instances ==0.1.2,
+             any.integer-conversion ==0.1.1,
+             any.integer-logarithms ==1.0.3.1,
+             integer-logarithms -check-bounds +integer-gmp,
+             any.mtl ==2.2.2,
+             any.network-uri ==2.6.4.2,
+             any.os-string ==2.0.3,
+             any.parsec ==3.1.16.1,
+             any.pretty ==1.1.3.6,
+             any.primitive ==0.9.0.0,
+             any.process ==1.6.17.0,
+             any.random ==1.2.1.2,
+             any.regex-base ==0.94.0.2,
+             any.regex-tdfa ==1.3.2.2,
+             regex-tdfa +doctest -force-o2,
+             any.rts ==1.0.2,
+             any.scientific ==0.3.8.0,
+             scientific -integer-simple,
+             any.semialign ==1.3.1,
+             semialign +semigroupoids,
+             any.semigroupoids ==6.0.1,
+             semigroupoids +comonad +containers +contravariant +distributive +tagged +unordered-containers,
+             any.splitmix ==0.1.0.5,
+             splitmix -optimised-mixer,
+             any.stm ==2.5.1.0,
+             any.strict ==0.5,
+             any.tagged ==0.8.8,
+             tagged +deepseq +transformers,
+             any.template-haskell ==2.19.0.0,
+             any.text ==2.0.2,
+             any.text-iso8601 ==0.1.1,
+             any.text-short ==0.1.6,
+             text-short -asserts,
+             any.th-abstraction ==0.7.0.0,
+             any.th-compat ==0.1.5,
+             any.these ==1.2.1,
+             any.time ==1.12.2,
+             any.time-compat ==1.9.7,
+             any.transformers ==0.5.6.2,
+             any.transformers-compat ==0.7.2,
+             transformers-compat -five +five-three -four +generic-deriving +mtl -three -two,
+             any.unix ==2.7.3,
+             any.unordered-containers ==0.2.20,
+             unordered-containers -debug,
+             any.uuid-types ==1.0.6,
+             any.vector ==0.13.1.0,
+             vector +boundschecks -internalchecks -unsafechecks -wall,
+             any.vector-stream ==0.1.0.1,
+             any.witherable ==0.5
+index-state: hackage.haskell.org 2024-06-17T00:48:51Z
--- a/build/linux.riscv64/tag
+++ b/build/linux.riscv64/tag
@ -0,0 +1 @@
+koalaman/scbuilder-linux-riscv64
--- a/build/linux.x86_64/Dockerfile
+++ b/build/linux.x86_64/Dockerfile
@ -1,4 +1,8 @@
-FROM alpine:latest
+FROM alpine:3.16
+# alpine:3.16 (GHC 9.0.1):  5.8 megabytes
+# alpine:3.17 (GHC 9.0.2): 15.0 megabytes
+# alpine:3.18 (GHC 9.4.4): 29.0 megabytes
+# alpine:3.19 (GHC 9.4.7): 29.0 megabytes

 ENV TARGETNAME linux.x86_64

--- a/build/windows.x86_64/Dockerfile
+++ b/build/windows.x86_64/Dockerfile
@ -12,7 +12,7 @@ WORKDIR /haskell
 RUN curl -L "https://downloads.haskell.org/~ghc/8.10.4/ghc-8.10.4-x86_64-unknown-mingw32.tar.xz" | tar xJ --strip-components=1
 WORKDIR /haskell/bin
 RUN curl -L "https://downloads.haskell.org/~cabal/cabal-install-3.2.0.0/cabal-install-3.2.0.0-x86_64-unknown-mingw32.zip" | busybox unzip -
-RUN curl -L "https://curl.se/windows/dl-7.84.0/curl-7.84.0-win64-mingw.zip" | busybox unzip - && mv curl-7.84.0-win64-mingw/bin/* .
+RUN curl -L "https://curl.se/windows/dl-8.7.1_7/curl-8.7.1_7-win64-mingw.zip" | busybox unzip - && mv curl-*-win64-mingw/bin/* .
 ENV WINEPATH /haskell/bin

 # It's unknown whether Cabal on Windows suffers from the same issue
--- a/build/windows.x86_64/build
+++ b/build/windows.x86_64/build
@ -8,7 +8,6 @@ set -xe
  tar xzv --strip-components=1
  chmod +x striptests && ./striptests
  mkdir "$TARGETNAME"
-  cabal update
  ( IFS=';'; cabal build $CABALOPTS )
  find dist*/ -name shellcheck.exe -type f -ls -exec mv {} "$TARGETNAME/" \;
  ls -l "$TARGETNAME"
--- a/shellcheck.1.md
+++ b/shellcheck.1.md
@ -56,6 +56,13 @@ not warn at all, as `ksh` supports decimals in arithmetic contexts.
    options are cumulative, but all the codes can be specified at once,
    comma-separated as a single argument.

+**--extended-analysis=true/false**
+
+:   Enable/disable Dataflow Analysis to identify more issues (default true). If
+    ShellCheck uses too much CPU/RAM when checking scripts with several
+    thousand lines of code, extended analysis can be disabled with this flag
+    or a directive. This flag overrides directives and rc files.
+
 **-f** *FORMAT*, **--format=***FORMAT*

 :   Specify the output format of shellcheck, which prints its results in the
@ -71,6 +78,11 @@ not warn at all, as `ksh` supports decimals in arithmetic contexts.

 :   Don't try to look for .shellcheckrc configuration files.

+**--rcfile** *RCFILE*
+
+:   Prefer the specified configuration file over searching for one
+    in the default locations.
+
 **-o**\ *NAME1*[,*NAME2*...],\ **--enable=***NAME1*[,*NAME2*...]

 :   Enable optional checks. The special name *all* enables all of them.
@ -85,7 +97,8 @@ not warn at all, as `ksh` supports decimals in arithmetic contexts.

 **-s**\ *shell*,\ **--shell=***shell*

-:   Specify Bourne shell dialect. Valid values are *sh*, *bash*, *dash* and *ksh*.
+:   Specify Bourne shell dialect. Valid values are *sh*, *bash*, *dash*, *ksh*,
+    and *busybox*.
    The default is to deduce the shell from the file's `shell` directive,
    shebang, or `.bash/.bats/.dash/.ksh` extension, in that order. *sh* refers to
    POSIX `sh` (not the system's), and will warn of portability issues.
@ -243,6 +256,12 @@ Valid keys are:
 :   Enable an optional check by name, as listed with **--list-optional**.
    Only file-wide `enable` directives are considered.

+**extended-analysis**
+:   Set to true/false to enable/disable dataflow analysis. Specifying
+    `# shellcheck extended-analysis=false` in particularly large (2000+ line)
+    auto-generated scripts will reduce ShellCheck's resource usage at the
+    expense of certain checks. Extended analysis is enabled by default.
+
 **external-sources**
 :   Set to `true` in `.shellcheckrc` to always allow ShellCheck to open
    arbitrary files from 'source' statements (the way most tools do).
@ -298,7 +317,7 @@ Here is an example `.shellcheckrc`:
    disable=SC2236

 If no `.shellcheckrc` is found in any of the parent directories, ShellCheck
-will look in `~/.shellcheckrc` followed by the XDG config directory
+will look in `~/.shellcheckrc` followed by the `$XDG_CONFIG_HOME`
 (usually `~/.config/shellcheckrc`) on Unix, or `%APPDATA%/shellcheckrc` on
 Windows. Only the first file found will be used.

@ -378,10 +397,10 @@ long list of wonderful contributors.

 # COPYRIGHT

-Copyright 2012-2022, Vidar Holen and contributors.
+Copyright 2012-2024, Vidar Holen and contributors.
 Licensed under the GNU General Public License version 3 or later,
 see https://gnu.org/licenses/gpl.html

 # SEE ALSO

-sh(1) bash(1)
+sh(1) bash(1) dash(1) ksh(1)
--- a/shellcheck.hs
+++ b/shellcheck.hs
@ -76,7 +76,8 @@ data Options = Options {
    externalSources  :: Bool,
    sourcePaths      :: [FilePath],
    formatterOptions :: FormatterOptions,
-    minSeverity      :: Severity
+    minSeverity      :: Severity,
+    rcfile           :: Maybe FilePath
 }

 defaultOptions = Options {
@ -86,7 +87,8 @@ defaultOptions = Options {
    formatterOptions = newFormatterOptions {
        foColorOption = ColorAuto
    },
-    minSeverity = StyleC
+    minSeverity = StyleC,
+    rcfile = Nothing
 }

 usageHeader = "Usage: shellcheck [OPTIONS...] FILES..."
@ -100,6 +102,8 @@ options = [
        (ReqArg (Flag "include") "CODE1,CODE2..") "Consider only given types of warnings",
    Option "e" ["exclude"]
        (ReqArg (Flag "exclude") "CODE1,CODE2..") "Exclude types of warnings",
+    Option "" ["extended-analysis"]
+        (ReqArg (Flag "extended-analysis") "bool") "Perform dataflow analysis (default true)",
    Option "f" ["format"]
        (ReqArg (Flag "format") "FORMAT") $
        "Output format (" ++ formatList ++ ")",
@ -107,6 +111,9 @@ options = [
        (NoArg $ Flag "list-optional" "true") "List checks disabled by default",
    Option "" ["norc"]
        (NoArg $ Flag "norc" "true") "Don't look for .shellcheckrc files",
+    Option "" ["rcfile"]
+        (ReqArg (Flag "rcfile") "RCFILE")
+        "Prefer the specified configuration file over searching for one",
    Option "o" ["enable"]
        (ReqArg (Flag "enable") "check1,check2..")
        "List of optional checks to enable (or 'all')",
@ -115,7 +122,7 @@ options = [
        "Specify path when looking for sourced files (\"SCRIPTDIR\" for script's dir)",
    Option "s" ["shell"]
        (ReqArg (Flag "shell") "SHELLNAME")
-        "Specify dialect (sh, bash, dash, ksh)",
+        "Specify dialect (sh, bash, dash, ksh, busybox)",
    Option "S" ["severity"]
        (ReqArg (Flag "severity") "SEVERITY")
        "Minimum severity of errors to consider (error, warning, info, style)",
@ -252,9 +259,9 @@ runFormatter sys format options files = do
                else SomeProblems

 parseEnum name value list =
-    case filter ((== value) . fst) list of
-        [(name, value)] -> return value
-        [] -> do
+    case lookup value list of
+        Just value -> return value
+        Nothing -> do
            printErr $ "Unknown value for --" ++ name ++ ". " ++
                       "Valid options are: " ++ (intercalate ", " $ map fst list)
            throwError SupportFailure
@ -367,6 +374,11 @@ parseOption flag options =
                }
            }

+        Flag "rcfile" str -> do
+            return options {
+                rcfile = Just str
+            }
+
        Flag "enable" value ->
            let cs = checkSpec options in return options {
                checkSpec = cs {
@ -374,6 +386,14 @@ parseOption flag options =
                }
            }

+        Flag "extended-analysis" str -> do
+            value <- parseBool str
+            return options {
+                checkSpec = (checkSpec options) {
+                    csExtendedAnalysis = Just value
+                }
+            }
+
        -- This flag is handled specially in 'process'
        Flag "format" _ -> return options

@ -391,12 +411,20 @@ parseOption flag options =
            throwError SyntaxFailure
        return (Prelude.read num :: Integer)

+    parseBool str = do
+        case str of
+            "true" -> return True
+            "false" -> return False
+            _ -> do
+                printErr $ "Invalid boolean, expected true/false: " ++ str
+                throwError SyntaxFailure
+
 ioInterface :: Options -> [FilePath] -> IO (SystemInterface IO)
 ioInterface options files = do
    inputs <- mapM normalize files
    cache <- newIORef emptyCache
    configCache <- newIORef ("", Nothing)
-    return SystemInterface {
+    return (newSystemInterface :: SystemInterface IO) {
        siReadFile = get cache inputs,
        siFindSource = findSourceFile inputs (sourcePaths options),
        siGetConfig = getConfig configCache
@ -441,18 +469,33 @@ ioInterface options files = do
        fallback :: FilePath -> IOException -> IO FilePath
        fallback path _ = return path

+
    -- Returns the name and contents of .shellcheckrc for the given file
-    getConfig cache filename = do
-        path <- normalize filename
-        let dir = takeDirectory path
-        (previousPath, result) <- readIORef cache
-        if dir == previousPath
-          then return result
-          else do
-            paths <- getConfigPaths dir
-            result <- findConfig paths
-            writeIORef cache (dir, result)
-            return result
+    getConfig cache filename =
+        case rcfile options of
+            Just file -> do
+                -- We have a specified rcfile. Ignore normal rcfile resolution.
+                (path, result) <- readIORef cache
+                if path == "/"
+                  then return result
+                  else do
+                    result <- readConfig file
+                    when (isNothing result) $
+                        hPutStrLn stderr $ "Warning: unable to read --rcfile " ++ file
+                    writeIORef cache ("/", result)
+                    return result
+
+            Nothing -> do
+                path <- normalize filename
+                let dir = takeDirectory path
+                (previousPath, result) <- readIORef cache
+                if dir == previousPath
+                  then return result
+                  else do
+                    paths <- getConfigPaths dir
+                    result <- findConfig paths
+                    writeIORef cache (dir, result)
+                    return result

    findConfig paths =
        case paths of
@ -490,7 +533,7 @@ ioInterface options files = do
      where
        handler :: FilePath -> IOException -> IO (String, Bool)
        handler file err = do
-            putStrLn $ file ++ ": " ++ show err
+            hPutStrLn stderr $ file ++ ": " ++ show err
            return ("", True)

    andM a b arg = do
--- a/snap/snapcraft.yaml
+++ b/snap/snapcraft.yaml
@ -23,7 +23,7 @@ description: |
      # snap connect shellcheck:removable-media

 version: git
-base: core18
+base: core20
 grade: stable
 confinement: strict

@ -40,16 +40,16 @@ parts:
    source: .
    build-packages:
      - cabal-install
-      - squid
+    stage-packages:
+      - libatomic1
    override-build: |
-      # See comments in .snapsquid.conf
-      [ "$http_proxy" ] && {
-        squid3 -f .snapsquid.conf
-        export http_proxy="http://localhost:8888"
-        sleep 3
-      }
+      # Give ourselves enough memory to build
+      dd if=/dev/zero of=/tmp/swap bs=1M count=2000
+      mkswap /tmp/swap
+      swapon /tmp/swap
+
      cabal sandbox init
-      cabal update || cat /var/log/squid/*
+      cabal update
      cabal install -j

      install -d $SNAPCRAFT_PART_INSTALL/usr/bin
--- a/src/ShellCheck/AST.hs
+++ b/src/ShellCheck/AST.hs
@ -138,7 +138,7 @@ data InnerToken t =
    | Inner_T_WhileExpression [t] [t]
    | Inner_T_Annotation [Annotation] t
    | Inner_T_Pipe String
-    | Inner_T_CoProc (Maybe String) t
+    | Inner_T_CoProc (Maybe Token) t
    | Inner_T_CoProcBody t
    | Inner_T_Include t
    | Inner_T_SourceCommand t t
@ -152,6 +152,7 @@ data Annotation =
    | ShellOverride String
    | SourcePath String
    | ExternalSources Bool
+    | ExtendedAnalysis Bool
    deriving (Show, Eq)
 data ConditionType = DoubleBracket | SingleBracket deriving (Show, Eq)

@ -205,7 +206,7 @@ pattern T_Annotation id anns t = OuterToken id (Inner_T_Annotation anns t)
 pattern T_Arithmetic id c = OuterToken id (Inner_T_Arithmetic c)
 pattern T_Array id t = OuterToken id (Inner_T_Array t)
 pattern TA_Sequence id l = OuterToken id (Inner_TA_Sequence l)
-pattern TA_Parentesis id t = OuterToken id (Inner_TA_Parenthesis t)
+pattern TA_Parenthesis id t = OuterToken id (Inner_TA_Parenthesis t)
 pattern T_Assignment id mode var indices value = OuterToken id (Inner_T_Assignment mode var indices value)
 pattern TA_Trinary id t1 t2 t3 = OuterToken id (Inner_TA_Trinary t1 t2 t3)
 pattern TA_Unary id op t1 = OuterToken id (Inner_TA_Unary op t1)
@ -258,7 +259,7 @@ pattern T_Subshell id l = OuterToken id (Inner_T_Subshell l)
 pattern T_UntilExpression id c l = OuterToken id (Inner_T_UntilExpression c l)
 pattern T_WhileExpression id c l = OuterToken id (Inner_T_WhileExpression c l)

-{-# COMPLETE T_AND_IF, T_Bang, T_Case, TC_Empty, T_CLOBBER, T_DGREAT, T_DLESS, T_DLESSDASH, T_Do, T_DollarSingleQuoted, T_Done, T_DSEMI, T_Elif, T_Else, T_EOF, T_Esac, T_Fi, T_For, T_Glob, T_GREATAND, T_Greater, T_If, T_In, T_Lbrace, T_Less, T_LESSAND, T_LESSGREAT, T_Literal, T_Lparen, T_NEWLINE, T_OR_IF, T_ParamSubSpecialChar, T_Pipe, T_Rbrace, T_Rparen, T_Select, T_Semi, T_SingleQuoted, T_Then, T_UnparsedIndex, T_Until, T_While, TA_Assignment, TA_Binary, TA_Expansion, T_AndIf, T_Annotation, T_Arithmetic, T_Array, TA_Sequence, TA_Parentesis, T_Assignment, TA_Trinary, TA_Unary, TA_Variable, T_Backgrounded, T_Backticked, T_Banged, T_BatsTest, T_BraceExpansion, T_BraceGroup, TC_And, T_CaseExpression, TC_Binary, TC_Group, TC_Nullary, T_Condition, T_CoProcBody, T_CoProc, TC_Or, TC_Unary, T_DollarArithmetic, T_DollarBraceCommandExpansion, T_DollarBraced, T_DollarBracket, T_DollarDoubleQuoted, T_DollarExpansion, T_DoubleQuoted, T_Extglob, T_FdRedirect, T_ForArithmetic, T_ForIn, T_Function, T_HereDoc, T_HereString, T_IfExpression, T_Include, T_IndexedElement, T_IoDuplicate, T_IoFile, T_NormalWord, T_OrIf, T_Pipeline, T_ProcSub, T_Redirecting, T_Script, T_SelectIn, T_SimpleCommand, T_SourceCommand, T_Subshell, T_UntilExpression, T_WhileExpression #-}
+{-# COMPLETE T_AND_IF, T_Bang, T_Case, TC_Empty, T_CLOBBER, T_DGREAT, T_DLESS, T_DLESSDASH, T_Do, T_DollarSingleQuoted, T_Done, T_DSEMI, T_Elif, T_Else, T_EOF, T_Esac, T_Fi, T_For, T_Glob, T_GREATAND, T_Greater, T_If, T_In, T_Lbrace, T_Less, T_LESSAND, T_LESSGREAT, T_Literal, T_Lparen, T_NEWLINE, T_OR_IF, T_ParamSubSpecialChar, T_Pipe, T_Rbrace, T_Rparen, T_Select, T_Semi, T_SingleQuoted, T_Then, T_UnparsedIndex, T_Until, T_While, TA_Assignment, TA_Binary, TA_Expansion, T_AndIf, T_Annotation, T_Arithmetic, T_Array, TA_Sequence, TA_Parenthesis, T_Assignment, TA_Trinary, TA_Unary, TA_Variable, T_Backgrounded, T_Backticked, T_Banged, T_BatsTest, T_BraceExpansion, T_BraceGroup, TC_And, T_CaseExpression, TC_Binary, TC_Group, TC_Nullary, T_Condition, T_CoProcBody, T_CoProc, TC_Or, TC_Unary, T_DollarArithmetic, T_DollarBraceCommandExpansion, T_DollarBraced, T_DollarBracket, T_DollarDoubleQuoted, T_DollarExpansion, T_DoubleQuoted, T_Extglob, T_FdRedirect, T_ForArithmetic, T_ForIn, T_Function, T_HereDoc, T_HereString, T_IfExpression, T_Include, T_IndexedElement, T_IoDuplicate, T_IoFile, T_NormalWord, T_OrIf, T_Pipeline, T_ProcSub, T_Redirecting, T_Script, T_SelectIn, T_SimpleCommand, T_SourceCommand, T_Subshell, T_UntilExpression, T_WhileExpression #-}

 instance Eq Token where
    OuterToken _ a == OuterToken _ b = a == b
--- a/src/ShellCheck/ASTLib.hs
+++ b/src/ShellCheck/ASTLib.hs
@ -31,6 +31,7 @@ import Data.Functor
 import Data.Functor.Identity
 import Data.List
 import Data.Maybe
+import qualified Data.List.NonEmpty as NE
 import qualified Data.Map as Map
 import Numeric (showHex)

@ -157,9 +158,10 @@ isFlag token =
        _ -> False

 -- Is this token a flag where the - is unquoted?
-isUnquotedFlag token = fromMaybe False $ do
-    str <- getLeadingUnquotedString token
-    return $ "-" `isPrefixOf` str
+isUnquotedFlag token =
+    case getLeadingUnquotedString token of
+        Just ('-':_) -> True
+        _ -> False

 -- getGnuOpts "erd:u:" will parse a list of arguments tokens like `read`
 --     -re -d : -u 3 bar
@ -444,6 +446,12 @@ getLiteralStringExt more = g
 -- Is this token a string literal?
 isLiteral t = isJust $ getLiteralString t

+-- Is this token a string literal number?
+isLiteralNumber t = fromMaybe False $ do
+    s <- getLiteralString t
+    guard $ all isDigit s
+    return True
+
 -- Escape user data for messages.
 -- Messages generally avoid repeating user data, but sometimes it's helpful.
 e4m = escapeForMessage
@ -758,8 +766,8 @@ prop_executableFromShebang6 = executableFromShebang "/usr/bin/env --split-string
 prop_executableFromShebang7 = executableFromShebang "/usr/bin/env --split-string bash -x" == "bash"
 prop_executableFromShebang8 = executableFromShebang "/usr/bin/env --split-string foo=bar bash -x" == "bash"
 prop_executableFromShebang9 = executableFromShebang "/usr/bin/env foo=bar dash" == "dash"
-prop_executableFromShebang10 = executableFromShebang "/bin/busybox sh" == "ash"
-prop_executableFromShebang11 = executableFromShebang "/bin/busybox ash" == "ash"
+prop_executableFromShebang10 = executableFromShebang "/bin/busybox sh" == "busybox sh"
+prop_executableFromShebang11 = executableFromShebang "/bin/busybox ash" == "busybox ash"

 -- Get the shell executable from a string like '/usr/bin/env bash'
 executableFromShebang :: String -> String
@ -776,7 +784,8 @@ executableFromShebang = shellFor
            [x] -> basename x
            (first:second:args) | basename first == "busybox" ->
                case basename second of
-                   "sh" -> "ash" -- busybox sh is ash
+                   "sh" -> "busybox sh"
+                   "ash" -> "busybox ash"
                   x -> x
            (first:args) | basename first == "env" ->
                fromEnvArgs args
@ -856,8 +865,7 @@ getBracedModifier s = headOrDefault "" $ do
 -- Get the variables from indices like ["x", "y"] in ${var[x+y+1]}
 prop_getIndexReferences1 = getIndexReferences "var[x+y+1]" == ["x", "y"]
 getIndexReferences s = fromMaybe [] $ do
-    match <- matchRegex re s
-    index <- match !!! 0
+    index:_ <- matchRegex re s
    return $ matchAllStrings variableNameRegex index
  where
    re = mkRegex "(\\[.*\\])"
@ -868,8 +876,7 @@ prop_getOffsetReferences3 = getOffsetReferences "[foo]:bar" == ["bar"]
 prop_getOffsetReferences4 = getOffsetReferences "[foo]:bar:baz" == ["bar", "baz"]
 getOffsetReferences mods = fromMaybe [] $ do
 -- if mods start with [, then drop until ]
-    match <- matchRegex re mods
-    offsets <- match !!! 1
+    _:offsets:_ <- matchRegex re mods
    return $ matchAllStrings variableNameRegex offsets
  where
    re = mkRegex "^(\\[.+\\])? *:([^-=?+].*)"
@ -886,11 +893,17 @@ isUnmodifiedParameterExpansion t =
            in getBracedReference str == str
        _ -> False

+-- Return the referenced variable if (and only if) it's an unmodified parameter expansion.
+getUnmodifiedParameterExpansion t =
+    case t of
+        T_DollarBraced _ _ list -> do
+            let str = concat $ oversimplify list
+            guard $ getBracedReference str == str
+            return str
+        _ -> Nothing
+
 --- A list of the element and all its parents up to the root node.
-getPath tree t = t :
-    case Map.lookup (getId t) tree of
-        Nothing     -> []
-        Just parent -> getPath tree parent
+getPath tree = NE.unfoldr $ \t -> (t, Map.lookup (getId t) tree)

 isClosingFileOp op =
    case op of
@ -903,5 +916,11 @@ getEnableDirectives root =
        T_Annotation _ list _ -> [s | EnableComment s <- list]
        _ -> []

+getExtendedAnalysisDirective :: Token -> Maybe Bool
+getExtendedAnalysisDirective root =
+    case root of
+        T_Annotation _ list _ -> listToMaybe $ [s | ExtendedAnalysis s <- list]
+        _ -> Nothing
+
 return []
 runTests = $quickCheckAll
--- a/src/ShellCheck/Analytics.hs
+++ b/src/ShellCheck/Analytics.hs
--- a/src/ShellCheck/AnalyzerLib.hs
+++ b/src/ShellCheck/AnalyzerLib.hs
@ -41,6 +41,7 @@ import Data.Char
 import Data.List
 import Data.Maybe
 import Data.Semigroup
+import qualified Data.List.NonEmpty as NE
 import qualified Data.Map as Map

 import Test.QuickCheck.All (forAllProperties)
@ -88,6 +89,8 @@ data Parameters = Parameters {
    hasSetE            :: Bool,
    -- Whether this script has 'set -o pipefail' anywhere.
    hasPipefail        :: Bool,
+    -- Whether this script has 'shopt -s execfail' anywhere.
+    hasExecfail        :: Bool,
    -- A linear (bad) analysis of data flow
    variableFlow       :: [StackData],
    -- A map from Id to Token
@ -103,7 +106,7 @@ data Parameters = Parameters {
    -- map from token id to start and end position
    tokenPositions     :: Map.Map Id (Position, Position),
    -- Result from Control Flow Graph analysis (including data flow analysis)
-    cfgAnalysis :: CF.CFGAnalysis
+    cfgAnalysis :: Maybe CF.CFGAnalysis
    } deriving (Show)

 -- TODO: Cache results of common AST ops here
@ -196,8 +199,10 @@ makeCommentWithFix severity id code str fix =
        }
    in force withFix

+-- makeParameters :: CheckSpec -> Parameters
 makeParameters spec = params
  where
+    extendedAnalysis = fromMaybe True $ msum [asExtendedAnalysis spec, getExtendedAnalysisDirective root]
    params = Parameters {
        rootNode = root,
        shellType = fromMaybe (determineShell (asFallbackShell spec) root) $ asShellType spec,
@ -206,26 +211,35 @@ makeParameters spec = params
            case shellType params of
                Bash -> isOptionSet "lastpipe" root
                Dash -> False
+                BusyboxSh -> False
                Sh   -> False
                Ksh  -> True,
        hasInheritErrexit =
            case shellType params of
                Bash -> isOptionSet "inherit_errexit" root
                Dash -> True
+                BusyboxSh -> True
                Sh   -> True
                Ksh  -> False,
        hasPipefail =
            case shellType params of
                Bash -> isOptionSet "pipefail" root
                Dash -> True
+                BusyboxSh -> isOptionSet "pipefail" root
                Sh   -> True
                Ksh  -> isOptionSet "pipefail" root,
+        hasExecfail =
+            case shellType params of
+                Bash -> isOptionSet "execfail" root
+                _ -> False,
        shellTypeSpecified = isJust (asShellType spec) || isJust (asFallbackShell spec),
        idMap = getTokenMap root,
        parentMap = getParentTree root,
        variableFlow = getVariableFlow params root,
        tokenPositions = asTokenPositions spec,
-        cfgAnalysis = CF.analyzeControlFlow cfParams root
+        cfgAnalysis = do
+            guard extendedAnalysis
+            return $ CF.analyzeControlFlow cfParams root
    }
    cfParams = CF.CFGParameters {
        CF.cfLastpipe = hasLastpipe params,
@ -284,8 +298,8 @@ prop_determineShell7 = determineShellTest "#! /bin/ash" == Dash
 prop_determineShell8 = determineShellTest' (Just Ksh) "#!/bin/sh" == Sh
 prop_determineShell9 = determineShellTest "#!/bin/env -S dash -x" == Dash
 prop_determineShell10 = determineShellTest "#!/bin/env --split-string= dash -x" == Dash
-prop_determineShell11 = determineShellTest "#!/bin/busybox sh" == Dash -- busybox sh is a specific shell, not posix sh
-prop_determineShell12 = determineShellTest "#!/bin/busybox ash" == Dash
+prop_determineShell11 = determineShellTest "#!/bin/busybox sh" == BusyboxSh -- busybox sh is a specific shell, not posix sh
+prop_determineShell12 = determineShellTest "#!/bin/busybox ash" == BusyboxSh

 determineShellTest = determineShellTest' Nothing
 determineShellTest' fallbackShell = determineShell fallbackShell . fromJust . prRoot . pScript
@ -333,14 +347,14 @@ isQuoteFree = isQuoteFreeNode False

 isQuoteFreeNode strict shell tree t =
    isQuoteFreeElement t ||
-        (fromMaybe False $ msum $ map isQuoteFreeContext $ drop 1 $ getPath tree t)
+        (fromMaybe False $ msum $ map isQuoteFreeContext $ NE.tail $ getPath tree t)
  where
    -- Is this node self-quoting in itself?
    isQuoteFreeElement t =
        case t of
-            T_Assignment {} -> assignmentIsQuoting t
-            T_FdRedirect {} -> True
-            _               -> False
+            T_Assignment id _ _ _ _ -> assignmentIsQuoting id
+            T_FdRedirect {}         -> True
+            _                       -> False

    -- Are any subnodes inherently self-quoting?
    isQuoteFreeContext t =
@ -350,7 +364,7 @@ isQuoteFreeNode strict shell tree t =
            TC_Binary _ DoubleBracket _ _ _ -> return True
            TA_Sequence {}                  -> return True
            T_Arithmetic {}                 -> return True
-            T_Assignment {}                 -> return $ assignmentIsQuoting t
+            T_Assignment id _ _ _ _         -> return $ assignmentIsQuoting id
            T_Redirecting {}                -> return False
            T_DoubleQuoted _ _              -> return True
            T_DollarDoubleQuoted _ _        -> return True
@ -365,11 +379,11 @@ isQuoteFreeNode strict shell tree t =
    -- Check whether this assignment is self-quoting due to being a recognized
    -- assignment passed to a Declaration Utility. This will soon be required
    -- by POSIX: https://austingroupbugs.net/view.php?id=351
-    assignmentIsQuoting t = shellParsesParamsAsAssignments || not (isAssignmentParamToCommand t)
+    assignmentIsQuoting id = shellParsesParamsAsAssignments || not (isAssignmentParamToCommand id)
    shellParsesParamsAsAssignments = shell /= Sh

    -- Is this assignment a parameter to a command like export/typeset/etc?
-    isAssignmentParamToCommand (T_Assignment id _ _ _ _) =
+    isAssignmentParamToCommand id =
        case Map.lookup id tree of
            Just (T_SimpleCommand _ _ (_:args)) -> id `elem` (map getId args)
            _ -> False
@ -395,7 +409,7 @@ isParamTo tree cmd =
 -- Get the parent command (T_Redirecting) of a Token, if any.
 getClosestCommand :: Map.Map Id Token -> Token -> Maybe Token
 getClosestCommand tree t =
-    findFirst findCommand $ getPath tree t
+    findFirst findCommand $ NE.toList $ getPath tree t
  where
    findCommand t =
        case t of
@ -409,7 +423,7 @@ getClosestCommandM t = do
    return $ getClosestCommand (parentMap params) t

 -- Is the token used as a command name (the first word in a T_SimpleCommand)?
-usedAsCommandName tree token = go (getId token) (tail $ getPath tree token)
+usedAsCommandName tree token = go (getId token) (NE.tail $ getPath tree token)
  where
    go currentId (T_NormalWord id [word]:rest)
        | currentId == getId word = go id rest
@ -426,7 +440,9 @@ getPathM t = do
    return $ getPath (parentMap params) t

 isParentOf tree parent child =
-    elem (getId parent) . map getId $ getPath tree child
+    any (\t -> parentId == getId t) (getPath tree child)
+  where
+    parentId = getId parent

 parents params = getPath (parentMap params)

@ -525,7 +541,9 @@ getModifiedVariables t =
        T_BatsTest {} -> [
            (t, t, "lines", DataArray SourceExternal),
            (t, t, "status", DataString SourceInteger),
-            (t, t, "output", DataString SourceExternal)
+            (t, t, "output", DataString SourceExternal),
+            (t, t, "stderr", DataString SourceExternal),
+            (t, t, "stderr_lines", DataArray SourceExternal)
            ]

        -- Count [[ -v foo ]] as an "assignment".
@ -547,8 +565,12 @@ getModifiedVariables t =
        T_FdRedirect _ ('{':var) op -> -- {foo}>&2 modifies foo
            [(t, t, takeWhile (/= '}') var, DataString SourceInteger) | not $ isClosingFileOp op]

-        T_CoProc _ name _ ->
-            [(t, t, fromMaybe "COPROC" name, DataArray SourceInteger)]
+        T_CoProc _ Nothing _ ->
+            [(t, t, "COPROC", DataArray SourceInteger)]
+
+        T_CoProc _ (Just token) _ -> do
+            name <- maybeToList $ getLiteralString token
+            [(t, t, name, DataArray SourceInteger)]

        --Points to 'for' rather than variable
        T_ForIn id str [] _ -> [(t, t, str, DataString SourceExternal)]
@ -810,7 +832,7 @@ getReferencedVariables parents t =
            return (context, token, getBracedReference str)

    isArithmeticAssignment t = case getPath parents t of
-        this: TA_Assignment _ "=" lhs _ :_ -> lhs == t
+        this NE.:| TA_Assignment _ "=" lhs _ :_ -> lhs == t
        _                                  -> False

 isDereferencingBinaryOp = (`elem` ["-eq", "-ne", "-lt", "-le", "-gt", "-ge"])
@ -892,15 +914,6 @@ supportsArrays Bash = True
 supportsArrays Ksh = True
 supportsArrays _ = False

-- Returns true if the shell is Bash or Ksh (sorry for the name, Ksh)
-isBashLike :: Parameters -> Bool
-isBashLike params =
-    case shellType params of
-        Bash -> True
-        Ksh -> True
-        Dash -> False
-        Sh -> False
-
 isTrueAssignmentSource c =
    case c of
        DataString SourceChecked -> False
@ -918,6 +931,14 @@ modifiesVariable params token name =
            Assignment (_, _, n, source) -> isTrueAssignmentSource source && n == name
            _ -> False

+isTestCommand t =
+    case t of
+        T_Condition {} -> True
+        T_SimpleCommand {} -> t `isCommand` "test"
+        T_Redirecting _ _ t -> isTestCommand t
+        T_Annotation _ _ t -> isTestCommand t
+        T_Pipeline _ _ [t] -> isTestCommand t
+        _ -> False

 return []
 runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])
--- a/src/ShellCheck/CFG.hs
+++ b/src/ShellCheck/CFG.hs
@ -51,6 +51,7 @@ import Control.Monad.Identity
 import Data.Array.Unboxed
 import Data.Array.ST
 import Data.List hiding (map)
+import qualified Data.List.NonEmpty as NE
 import Data.Maybe
 import qualified Data.Map as M
 import qualified Data.Set as S
@ -111,8 +112,8 @@ data CFEdge =

 -- Actions we track
 data CFEffect =
-    CFSetProps Scope String (S.Set CFVariableProp)
-    | CFUnsetProps Scope String (S.Set CFVariableProp)
+    CFSetProps (Maybe Scope) String (S.Set CFVariableProp)
+    | CFUnsetProps (Maybe Scope) String (S.Set CFVariableProp)
    | CFReadVariable String
    | CFWriteVariable String CFValue
    | CFWriteGlobal String CFValue
@ -192,7 +193,7 @@ buildGraph params root =
                    base

        idToRange = M.fromList mapping
-        isRealEdge (from, to, edge) = case edge of CFEFlow -> True; _ -> False
+        isRealEdge (from, to, edge) = case edge of CFEFlow -> True; CFEExit -> True; _ -> False
        onlyRealEdges = filter isRealEdge edges
        (_, mainExit) = fromJust $ M.lookup (getId root) idToRange

@ -294,19 +295,19 @@ removeUnnecessaryStructuralNodes (nodes, edges, mapping, association) =
    regularEdges = filter isRegularEdge edges
    inDegree = counter $ map (\(from,to,_) -> from) regularEdges
    outDegree = counter $ map (\(from,to,_) -> to) regularEdges
-    structuralNodes = S.fromList $ map fst $ filter isStructural nodes
+    structuralNodes = S.fromList [node | (node, CFStructuralNode) <- nodes]
    candidateNodes = S.filter isLinear structuralNodes
    edgesToCollapse = S.fromList $ filter filterEdges regularEdges

    remapping :: M.Map Node Node
-    remapping = foldl' (\m (new, old) -> M.insert old new m) M.empty $ map orderEdge $ S.toList edgesToCollapse
-    recursiveRemapping = M.fromList $ map (\c -> (c, recursiveLookup remapping c)) $ M.keys remapping
+    remapping = M.fromList $ map orderEdge $ S.toList edgesToCollapse
+    recursiveRemapping = M.mapWithKey (\c _ -> recursiveLookup remapping c) remapping

    filterEdges (a,b,_) =
        a `S.member` candidateNodes && b `S.member` candidateNodes

-    orderEdge (a,b,_) = if a < b then (a,b) else (b,a)
-    counter = foldl' (\map key -> M.insertWith (+) key 1 map) M.empty
+    orderEdge (a,b,_) = if a < b then (b,a) else (a,b)
+    counter = M.fromListWith (+) . map (\key -> (key, 1))
    isRegularEdge (_, _, CFEFlow) = True
    isRegularEdge _ = False

@ -316,11 +317,6 @@ removeUnnecessaryStructuralNodes (nodes, edges, mapping, association) =
            Nothing -> node
            Just x -> recursiveLookup map x

-    isStructural (node, label) =
-        case label of
-            CFStructuralNode -> True
-            _ -> False
-
    isLinear node =
        M.findWithDefault 0 node inDegree == 1
        && M.findWithDefault 0 node outDegree == 1
@ -494,7 +490,7 @@ build t = do
        TA_Binary _ _ a b -> sequentially [a,b]
        TA_Expansion _ list -> sequentially list
        TA_Sequence _ list -> sequentially list
-        TA_Parentesis _ t -> build t
+        TA_Parenthesis _ t -> build t

        TA_Trinary _ cond a b -> do
            condition <- build cond
@ -578,7 +574,7 @@ build t = do

        T_Array _ list -> sequentially list

-        T_Assignment {} -> buildAssignment DefaultScope t
+        T_Assignment {} -> buildAssignment Nothing t

        T_Backgrounded id body -> do
            start <- newStructuralNode
@ -614,15 +610,15 @@ build t = do

        T_CaseExpression id t [] -> build t

-        T_CaseExpression id t list -> do
+        T_CaseExpression id t list@(hd:tl) -> do
            start <- newStructuralNode
            token <- build t
-            branches <- mapM buildBranch list
+            branches <- mapM buildBranch (hd NE.:| tl)
            end <- newStructuralNode

-            let neighbors = zip branches $ tail branches
-            let (_, firstCond, _) = head branches
-            let (_, lastCond, lastBody) = last branches
+            let neighbors = zip (NE.toList branches) $ NE.tail branches
+            let (_, firstCond, _) = NE.head branches
+            let (_, lastCond, lastBody) = NE.last branches

            linkRange start token
            linkRange token firstCond
@ -672,10 +668,18 @@ build t = do
            status <- newNodeRange $ CFSetExitCode id
            linkRange cond status

-        T_CoProc id maybeName t -> do
-            let name = fromMaybe "COPROC" maybeName
+        T_CoProc id maybeNameToken t -> do
+            -- If unspecified, "COPROC". If not a constant string, Nothing.
+            let maybeName = case maybeNameToken of
+                    Just x -> getLiteralString x
+                    Nothing -> Just "COPROC"
+
+            let parentNode = case maybeName of
+                    Just str -> applySingle $ IdTagged id $ CFWriteVariable str CFValueArray
+                    Nothing -> CFStructuralNode
+
            start <- newStructuralNode
-            parent <- newNodeRange $ applySingle $ IdTagged id $ CFWriteVariable name CFValueArray
+            parent <- newNodeRange parentNode
            child <- subshell id "coproc" $ build t
            end <- newNodeRange $ CFSetExitCode id

@ -857,8 +861,8 @@ build t = do
            status <- newNodeRange (CFSetExitCode id)
            linkRange assignments status

-        T_SimpleCommand id vars list@(cmd:_) ->
-            handleCommand t vars list $ getUnquotedLiteral cmd
+        T_SimpleCommand id vars (cmd:args) ->
+            handleCommand t vars (cmd NE.:| args) $ getUnquotedLiteral cmd

        T_SingleQuoted _ _ -> none

@ -887,7 +891,9 @@ build t = do
        T_Less _ -> none
        T_ParamSubSpecialChar _ _ -> none

-        x -> error ("Unimplemented: " ++ show x)
+        x -> do
+            error ("Unimplemented: " ++ show x) -- STRIP
+            none

 --  Still in `where` clause
    forInHelper id name words body = do
@ -923,8 +929,8 @@ handleCommand cmd vars args literalCmd = do
    -- TODO: Handle assignments in declaring commands

    case literalCmd of
-        Just "exit" -> regularExpansion vars args $ handleExit
-        Just "return" -> regularExpansion vars args $ handleReturn
+        Just "exit" -> regularExpansion vars (NE.toList args) $ handleExit
+        Just "return" -> regularExpansion vars (NE.toList args) $ handleReturn
        Just "unset" -> regularExpansionWithStatus vars args $ handleUnset args

        Just "declare" -> handleDeclare args
@ -947,14 +953,14 @@ handleCommand cmd vars args literalCmd = do
        -- This will mostly behave like 'command' but ok
        Just "builtin" ->
            case args of
-                [_] -> regular
-                (_:newargs@(newcmd:_)) ->
-                    handleCommand newcmd vars newargs $ getLiteralString newcmd
+                _ NE.:| [] -> regular
+                (_ NE.:| newcmd:newargs) ->
+                    handleCommand newcmd vars (newcmd NE.:| newargs) $ getLiteralString newcmd
        Just "command" ->
            case args of
-                [_] -> regular
-                (_:newargs@(newcmd:_)) ->
-                    handleOthers (getId newcmd) vars newargs $ getLiteralString newcmd
+                _ NE.:| [] -> regular
+                (_ NE.:| newcmd:newargs) ->
+                    handleOthers (getId newcmd) vars (newcmd NE.:| newargs) $ getLiteralString newcmd
        _ -> regular

  where
@ -982,7 +988,7 @@ handleCommand cmd vars args literalCmd = do
                unreachable <- newNode CFUnreachable
                return $ Range ret unreachable

-    handleUnset (cmd:args) = do
+    handleUnset (cmd NE.:| args) = do
        case () of
                _ | "n" `elem` flagNames -> unsetWith CFUndefineNameref
                _ | "v" `elem` flagNames -> unsetWith CFUndefineVariable
@ -994,14 +1000,14 @@ handleCommand cmd vars args literalCmd = do
        (names, flags) = partition (null . fst) pairs
        flagNames = map fst flags
        literalNames :: [(Token, String)] -- Literal names to unset, e.g. [(myfuncToken, "myfunc")]
-        literalNames = mapMaybe (\(_, t) -> getLiteralString t >>= (return . (,) t)) names
+        literalNames = mapMaybe (\(_, t) -> (,) t <$> getLiteralString t) names
        -- Apply a constructor like CFUndefineVariable to each literalName, and tag with its id
        unsetWith c = newNodeRange $ CFApplyEffects $ map (\(token, name) -> IdTagged (getId token) $ c name) literalNames


    variableAssignRegex = mkRegex "^([_a-zA-Z][_a-zA-Z0-9]*)="

-    handleDeclare (cmd:args) = do
+    handleDeclare (cmd NE.:| args) = do
        isFunc <- asks cfIsFunction
        -- This is a bit of a kludge: we don't have great support for things like
        -- 'declare -i x=$x' so do one round with declare x=$x, followed by declare -i x
@ -1028,9 +1034,9 @@ handleCommand cmd vars args literalCmd = do

        scope isFunc =
            case () of
-                _ | global -> GlobalScope
-                _ | isFunc -> LocalScope
-                _ -> DefaultScope
+                _ | global -> Just GlobalScope
+                _ | isFunc -> Just LocalScope
+                _ -> Nothing

        addedProps = S.fromList $ concat $ [
            [ CFVPArray | array ],
@ -1058,7 +1064,7 @@ handleCommand cmd vars args literalCmd = do
            let
                id = getId t
                pre = [t]
-                literal = fromJust $ getLiteralStringExt (const $ Just "\0") t
+                literal = getLiteralStringDef "\0" t
                isKnown = '\0' `notElem` literal
                match = fmap head $ variableAssignRegex `matchRegex` literal
                name = fromMaybe literal match
@ -1090,7 +1096,7 @@ handleCommand cmd vars args literalCmd = do
            in
                concatMap (drop 1) plusses

-    handlePrintf (cmd:args) =
+    handlePrintf (cmd NE.:| args) =
        newNodeRange $ CFApplyEffects $ maybeToList findVar
      where
        findVar = do
@ -1099,7 +1105,7 @@ handleCommand cmd vars args literalCmd = do
            name <- getLiteralString arg
            return $ IdTagged (getId arg) $ CFWriteVariable name CFValueString

-    handleWait (cmd:args) =
+    handleWait (cmd NE.:| args) =
        newNodeRange $ CFApplyEffects $ maybeToList findVar
      where
        findVar = do
@ -1108,7 +1114,7 @@ handleCommand cmd vars args literalCmd = do
            name <- getLiteralString arg
            return $ IdTagged (getId arg) $ CFWriteVariable name CFValueInteger

-    handleMapfile (cmd:args) =
+    handleMapfile (cmd NE.:| args) =
        newNodeRange $ CFApplyEffects [findVar]
      where
        findVar =
@ -1128,7 +1134,7 @@ handleCommand cmd vars args literalCmd = do
            guard $ isVariableName name
            return (getId c, name)

-    handleRead (cmd:args) = newNodeRange $ CFApplyEffects main
+    handleRead (cmd NE.:| args) = newNodeRange $ CFApplyEffects main
      where
        main = fromMaybe fallback $ do
            flags <- getGnuOpts flagsForRead args
@ -1158,7 +1164,7 @@ handleCommand cmd vars args literalCmd = do
            in
                map (\(id, name) -> IdTagged id $ CFWriteVariable name value) namesOrDefault

-    handleDEFINE (cmd:args) =
+    handleDEFINE (cmd NE.:| args) =
        newNodeRange $ CFApplyEffects $ maybeToList findVar
      where
        findVar = do
@ -1168,14 +1174,14 @@ handleCommand cmd vars args literalCmd = do
            return $ IdTagged (getId name) $ CFWriteVariable str CFValueString

    handleOthers id vars args cmd =
-        regularExpansion vars args $ do
+        regularExpansion vars (NE.toList args) $ do
            exe <- newNodeRange $ CFExecuteCommand cmd
            status <- newNodeRange $ CFSetExitCode id
            linkRange exe status

    regularExpansion vars args p = do
            args <- sequentially args
-            assignments <- mapM (buildAssignment PrefixScope) vars
+            assignments <- mapM (buildAssignment (Just PrefixScope)) vars
            exe <- p
            dropAssignments <-
                if null vars
@ -1187,15 +1193,15 @@ handleCommand cmd vars args literalCmd = do

            linkRanges $ [args] ++ assignments ++ [exe] ++ dropAssignments

-    regularExpansionWithStatus vars args@(cmd:_) p = do
-        initial <- regularExpansion vars args p
+    regularExpansionWithStatus vars args@(cmd NE.:| _) p = do
+        initial <- regularExpansion vars (NE.toList args) p
        status <- newNodeRange $ CFSetExitCode (getId cmd)
        linkRange initial status


 none = newStructuralNode

-data Scope = DefaultScope | GlobalScope | LocalScope | PrefixScope
+data Scope = GlobalScope | LocalScope | PrefixScope
  deriving (Eq, Ord, Show, Generic, NFData)

 buildAssignment scope t = do
@ -1209,10 +1215,10 @@ buildAssignment scope t = do
                let valueType = if null indices then f id value else CFValueArray
                let scoper =
                                case scope of
-                                    PrefixScope -> CFWritePrefix
-                                    LocalScope -> CFWriteLocal
-                                    GlobalScope -> CFWriteGlobal
-                                    DefaultScope -> CFWriteVariable
+                                    Just PrefixScope -> CFWritePrefix
+                                    Just LocalScope -> CFWriteLocal
+                                    Just GlobalScope -> CFWriteGlobal
+                                    Nothing -> CFWriteVariable
                write <- newNodeRange $ applySingle $ IdTagged id $ scoper var valueType
                linkRanges [expand, index, read, write]
              where
@ -1301,7 +1307,10 @@ findPostDominators mainexit graph = asArray
    reversed = grev withExitEdges
    postDoms = dom reversed mainexit
    (_, maxNode) = nodeRange graph
-    asArray = array (0, maxNode) postDoms
+    -- Holes in the array cause "Exception: (Array.!): undefined array element" while
+    -- inspecting/debugging, so fill the array first and then update.
+    initializedArray = listArray (0, maxNode) $ repeat []
+    asArray = initializedArray // postDoms

 return []
 runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])
--- a/src/ShellCheck/CFGAnalysis.hs
+++ b/src/ShellCheck/CFGAnalysis.hs
@ -59,6 +59,8 @@ module ShellCheck.CFGAnalysis (
    ,getIncomingState
    ,getOutgoingState
    ,doesPostDominate
+    ,variableMayBeDeclaredInteger
+    ,variableMayBeAssignedInteger
    ,ShellCheck.CFGAnalysis.runTests -- STRIP
    ) where

@ -131,7 +133,7 @@ internalToExternal s =
            literalValue = Nothing
        }
    }
-    flatVars = M.unionsWith (\_ last -> last) $ map mapStorage [sGlobalValues s, sLocalValues s, sPrefixValues s]
+    flatVars = M.unions $ map mapStorage [sPrefixValues s, sLocalValues s, sGlobalValues s]

 -- Conveniently get the state before a token id
 getIncomingState :: CFGAnalysis -> Id -> Maybe ProgramState
@ -153,6 +155,20 @@ doesPostDominate analysis target base = fromMaybe False $ do
    (targetStart, _) <- M.lookup target $ tokenToRange analysis
    return $ targetStart `elem` (postDominators analysis ! baseEnd)

+-- See if any execution path results in the variable containing a state
+variableMayHaveState :: ProgramState -> String -> CFVariableProp -> Maybe Bool
+variableMayHaveState state var property = do
+    value <- M.lookup var $ variablesInScope state
+    return $ any (S.member property) $ variableProperties value
+
+-- See if any execution path declares the variable an integer (declare -i).
+variableMayBeDeclaredInteger state var = variableMayHaveState state var CFVPInteger
+
+-- See if any execution path suggests the variable may contain an integer value
+variableMayBeAssignedInteger state var = do
+    value <- M.lookup var $ variablesInScope state
+    return $ (numericalStatus $ variableValue value) >= NumericalStatusMaybe
+
 getDataForNode analysis node = M.lookup node $ nodeToData analysis

 -- The current state of data flow at a point in the program, potentially as a diff
@ -283,7 +299,6 @@ depsToState set = foldl insert newInternalState $ S.toList set
                    PrefixScope -> (sPrefixValues, insertPrefix)
                    LocalScope -> (sLocalValues, insertLocal)
                    GlobalScope -> (sGlobalValues, insertGlobal)
-                    DefaultScope -> error $ pleaseReport "Unresolved scope in dependency"

            alreadyExists = isJust $ vmLookup name $ mapToCheck state
        in
@ -657,7 +672,7 @@ vmPatch base diff =
        _ | vmIsQuickEqual base diff -> diff
        _ -> VersionedMap {
            mapVersion = -1,
-            mapStorage = M.unionWith (flip const) (mapStorage base) (mapStorage diff)
+            mapStorage = M.union (mapStorage diff) (mapStorage base)
        }

 -- Set a variable. This includes properties. Applies it to the appropriate scope.
@ -814,7 +829,7 @@ lookupStack' functionOnly get dep def ctx key = do
    f (s:rest) = do
        -- Go up the stack until we find the value, and add
        -- a dependency on each state (including where it was found)
-        res <- fromMaybe (f rest) (return <$> get (stackState s) key)
+        res <- maybe (f rest) return (get (stackState s) key)
        modifySTRef (dependencies s) $ S.insert $ dep key res
        return res

@ -1104,34 +1119,34 @@ transferEffect ctx effect =

        CFSetProps scope name props ->
            case scope of
-                DefaultScope -> do
+                Nothing -> do
                    state <- readVariable ctx name
                    writeVariable ctx name $ addProperties props state
-                GlobalScope -> do
+                Just GlobalScope -> do
                    state <- readGlobal ctx name
                    writeGlobal ctx name $ addProperties props state
-                LocalScope -> do
+                Just LocalScope -> do
                    out <- readSTRef (cOutput ctx)
                    state <- readLocal ctx name
                    writeLocal ctx name $ addProperties props state
-                PrefixScope -> do
+                Just PrefixScope -> do
                    -- Prefix values become local
                    state <- readLocal ctx name
                    writeLocal ctx name $ addProperties props state

        CFUnsetProps scope name props ->
            case scope of
-                DefaultScope -> do
+                Nothing -> do
                    state <- readVariable ctx name
                    writeVariable ctx name $ removeProperties props state
-                GlobalScope -> do
+                Just GlobalScope -> do
                    state <- readGlobal ctx name
                    writeGlobal ctx name $ removeProperties props state
-                LocalScope -> do
+                Just LocalScope -> do
                    out <- readSTRef (cOutput ctx)
                    state <- readLocal ctx name
                    writeLocal ctx name $ removeProperties props state
-                PrefixScope -> do
+                Just PrefixScope -> do
                    -- Prefix values become local
                    state <- readLocal ctx name
                    writeLocal ctx name $ removeProperties props state
@ -1271,7 +1286,7 @@ dataflow ctx entry = do
            else do
                let (next, rest) = S.deleteFindMin ps
                nexts <- process states next
-                writeSTRef pending $ foldl (flip S.insert) rest nexts
+                writeSTRef pending $ S.union (S.fromList nexts) rest
                f (n-1) pending states

    process states node = do
@ -1335,7 +1350,7 @@ analyzeControlFlow params t =

        -- All nodes we've touched
        invocations <- readSTRef $ cInvocations ctx
-        let invokedNodes = M.fromDistinctAscList $ map (\c -> (c, ())) $ S.toList $ M.keysSet $ groupByNode $ M.map snd invocations
+        let invokedNodes = M.fromSet (const ()) $ S.unions $ map (M.keysSet . snd) $ M.elems invocations

        -- Invoke all functions that were declared but not invoked
        -- This is so that we still get warnings for dead code
@ -1358,7 +1373,7 @@ analyzeControlFlow params t =

        -- Fill in the map with unreachable states for anything we didn't get to
        let baseStates = M.fromDistinctAscList $ map (\c -> (c, (unreachableState, unreachableState))) $ uncurry enumFromTo $ nodeRange $ cfGraph cfg
-        let allStates = M.unionWith (flip const) baseStates invokedStates
+        let allStates = M.union invokedStates baseStates

        -- Convert to external states
        let nodeToData = M.map (\(a,b) -> (internalToExternal a, internalToExternal b)) allStates
--- a/src/ShellCheck/Checker.hs
+++ b/src/ShellCheck/Checker.hs
@ -25,6 +25,7 @@ import ShellCheck.ASTLib
 import ShellCheck.Interface
 import ShellCheck.Parser

+import Debug.Trace -- DO NOT SUBMIT
 import Data.Either
 import Data.Functor
 import Data.List
@ -86,6 +87,7 @@ checkScript sys spec = do
                    asCheckSourced = csCheckSourced spec,
                    asExecutionMode = Executed,
                    asTokenPositions = tokenPositions,
+                    asExtendedAnalysis = csExtendedAnalysis spec,
                    asOptionalChecks = getEnableDirectives root ++ csOptionalChecks spec
                } where as = newAnalysisSpec root
        let analysisMessages =
@ -508,5 +510,55 @@ prop_rcCanSuppressEarlyProblems2 = null result
        csScript = "!/bin/bash\necho 'hello world'"
    }

+prop_sourceWithHereDocWorks = null result
+  where
+    result = checkWithIncludes [("bar", "true\n")] "source bar << eof\nlol\neof"
+
+prop_hereDocsAreParsedWithoutTrailingLinefeed = 1044 `elem` result
+  where
+    result = check "cat << eof"
+
+prop_hereDocsWillHaveParsedIndices = null result
+  where
+    result = check "#!/bin/bash\nmy_array=(a b)\ncat <<EOF >> ./test\n $(( 1 + my_array[1] ))\nEOF"
+
+prop_rcCanSuppressDfa = null result
+  where
+    result = checkWithRc "extended-analysis=false" emptyCheckSpec {
+        csScript = "#!/bin/sh\nexit; foo;"
+    }
+
+prop_fileCanSuppressDfa = null $ traceShowId result
+  where
+    result = checkWithRc "" emptyCheckSpec {
+        csScript = "#!/bin/sh\n# shellcheck extended-analysis=false\nexit; foo;"
+    }
+
+prop_fileWinsWhenSuppressingDfa1 = null result
+  where
+    result = checkWithRc "extended-analysis=true" emptyCheckSpec {
+        csScript = "#!/bin/sh\n# shellcheck extended-analysis=false\nexit; foo;"
+    }
+
+prop_fileWinsWhenSuppressingDfa2 = result == [2317]
+  where
+    result = checkWithRc "extended-analysis=false" emptyCheckSpec {
+        csScript = "#!/bin/sh\n# shellcheck extended-analysis=true\nexit; foo;"
+    }
+
+prop_flagWinsWhenSuppressingDfa1 = result == [2317]
+  where
+    result = checkWithRc "extended-analysis=false" emptyCheckSpec {
+        csScript = "#!/bin/sh\n# shellcheck extended-analysis=false\nexit; foo;",
+        csExtendedAnalysis = Just True
+    }
+
+prop_flagWinsWhenSuppressingDfa2 = null result
+  where
+    result = checkWithRc "extended-analysis=true" emptyCheckSpec {
+        csScript = "#!/bin/sh\n# shellcheck extended-analysis=true\nexit; foo;",
+        csExtendedAnalysis = Just False
+    }
+
 return []
 runTests = $quickCheckAll
--- a/src/ShellCheck/Checks/Commands.hs
+++ b/src/ShellCheck/Checks/Commands.hs
@ -20,6 +20,7 @@
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE MultiWayIf #-}
+{-# LANGUAGE PatternGuards #-}

 -- This module contains checks that examine specific commands by name.
 module ShellCheck.Checks.Commands (checker, optionalChecks, ShellCheck.Checks.Commands.runTests) where
@ -42,6 +43,7 @@ import Data.Functor.Identity
 import qualified Data.Graph.Inductive.Graph as G
 import Data.List
 import Data.Maybe
+import qualified Data.List.NonEmpty as NE
 import qualified Data.Map.Strict as M
 import qualified Data.Set as S
 import Test.QuickCheck.All (forAllProperties)
@ -181,16 +183,15 @@ checkCommand :: M.Map CommandName (Token -> Analysis) -> Token -> Analysis
 checkCommand map t@(T_SimpleCommand id cmdPrefix (cmd:rest)) = sequence_ $ do
    name <- getLiteralString cmd
    return $
-        if '/' `elem` name
-        then
-            M.findWithDefault nullCheck (Basename $ basename name) map t
-        else if name == "builtin" && not (null rest) then
-            let t' = T_SimpleCommand id cmdPrefix rest
-                selectedBuiltin = fromMaybe "" $ getLiteralString . head $ rest
-            in M.findWithDefault nullCheck (Exactly selectedBuiltin) map t'
-        else do
-            M.findWithDefault nullCheck (Exactly name) map t
-            M.findWithDefault nullCheck (Basename name) map t
+        if | '/' `elem` name ->
+               M.findWithDefault nullCheck (Basename $ basename name) map t
+           | name == "builtin", (h:_) <- rest ->
+               let t' = T_SimpleCommand id cmdPrefix rest
+                   selectedBuiltin = onlyLiteralString h
+               in M.findWithDefault nullCheck (Exactly selectedBuiltin) map t'
+           | otherwise -> do
+               M.findWithDefault nullCheck (Exactly name) map t
+               M.findWithDefault nullCheck (Basename name) map t

  where
    basename = reverse . takeWhile (/= '/') . reverse
@ -299,7 +300,7 @@ checkExpr = CommandCheck (Basename "expr") f where
                    "'expr' expects 3+ arguments but sees 1. Make sure each operator/operand is a separate argument, and escape <>&|."

            [first, second] |
-                (fromMaybe "" $ getLiteralString first) /= "length"
+                onlyLiteralString first /= "length"
                  && not (willSplit first || willSplit second) -> do
                    checkOp first
                    warn (getId t) 2307
@ -930,7 +931,7 @@ prop_checkTimedCommand2 = verify checkTimedCommand "#!/bin/dash\ntime ( foo; bar
 prop_checkTimedCommand3 = verifyNot checkTimedCommand "#!/bin/sh\ntime sleep 1"
 checkTimedCommand = CommandCheck (Exactly "time") f where
    f (T_SimpleCommand _ _ (c:args@(_:_))) =
-        whenShell [Sh, Dash] $ do
+        whenShell [Sh, Dash, BusyboxSh] $ do
            let cmd = last args -- "time" is parsed with a command as argument
            when (isPiped cmd) $
                warn (getId c) 2176 "'time' is undefined for pipelines. time single stage or bash -c instead."
@ -954,7 +955,7 @@ checkTimedCommand = CommandCheck (Exactly "time") f where
 prop_checkLocalScope1 = verify checkLocalScope "local foo=3"
 prop_checkLocalScope2 = verifyNot checkLocalScope "f() { local foo=3; }"
 checkLocalScope = CommandCheck (Exactly "local") $ \t ->
-    whenShell [Bash, Dash] $ do -- Ksh allows it, Sh doesn't support local
+    whenShell [Bash, Dash, BusyboxSh] $ do -- Ksh allows it, Sh doesn't support local
        path <- getPathM t
        unless (any isFunctionLike path) $
            err (getId $ getCommandTokenOrThis t) 2168 "'local' is only valid in functions."
@ -1005,8 +1006,8 @@ checkWhileGetoptsCase = CommandCheck (Exactly "getopts") f
        sequence_ $ do
            options <- getLiteralString arg1
            getoptsVar <- getLiteralString name
-            (T_WhileExpression _ _ body) <- findFirst whileLoop path
-            caseCmd@(T_CaseExpression _ var _) <- mapMaybe findCase body !!! 0
+            (T_WhileExpression _ _ body) <- findFirst whileLoop (NE.toList path)
+            T_CaseExpression id var list <- mapMaybe findCase body !!! 0

            -- Make sure getopts name and case variable matches
            [T_DollarBraced _ _ bracedWord] <- return $ getWordParts var
@ -1016,11 +1017,11 @@ checkWhileGetoptsCase = CommandCheck (Exactly "getopts") f
            -- Make sure the variable isn't modified
            guard . not $ modifiesVariable params (T_BraceGroup (Id 0) body) getoptsVar

-            return $ check (getId arg1) (map (:[]) $ filter (/= ':') options) caseCmd
+            return $ check (getId arg1) (map (:[]) $ filter (/= ':') options) id list
    f _ = return ()

-    check :: Id -> [String] -> Token -> Analysis
-    check optId opts (T_CaseExpression id _ list) = do
+    check :: Id -> [String] -> Id -> [(CaseType, [Token], [Token])] -> Analysis
+    check optId opts id list = do
            unless (Nothing `M.member` handledMap) $ do
                mapM_ (warnUnhandled optId id) $ catMaybes $ M.keys notHandled

@ -1236,8 +1237,7 @@ checkSudoArgs = CommandCheck (Basename "sudo") f
  where
    f t = sequence_ $ do
        opts <- parseOpts $ arguments t
-        let nonFlags = [x | ("",(x, _)) <- opts]
-        commandArg <- nonFlags !!! 0
+        (_,(commandArg, _)) <- find (null . fst) opts
        command <- getLiteralString commandArg
        guard $ command `elem` builtins
        return $ warn (getId t) 2232 $ "Can't use sudo with builtins like " ++ command ++ ". Did you want sudo sh -c .. instead?"
@ -1430,26 +1430,27 @@ prop_checkBackreferencingDeclaration6 = verify (checkBackreferencingDeclaration
 prop_checkBackreferencingDeclaration7 = verify (checkBackreferencingDeclaration "declare") "declare x=var $k=$x"
 checkBackreferencingDeclaration cmd = CommandCheck (Exactly cmd) check
  where
-    check t = foldM_ perArg M.empty $ arguments t
+    check t = do
+        maybeCfga <- asks cfgAnalysis
+        mapM_ (\cfga -> foldM_ (perArg cfga) M.empty $ arguments t) maybeCfga

-    perArg leftArgs t =
+    perArg cfga leftArgs t =
        case t of
            T_Assignment id _ name idx t -> do
-                warnIfBackreferencing leftArgs $ t:idx
+                warnIfBackreferencing cfga leftArgs $ t:idx
                return $ M.insert name id leftArgs
            t -> do
-                warnIfBackreferencing leftArgs [t]
+                warnIfBackreferencing cfga leftArgs [t]
                return leftArgs

-    warnIfBackreferencing backrefs l = do
-        references <- findReferences l
+    warnIfBackreferencing cfga backrefs l = do
+        references <- findReferences cfga l
        let reused = M.intersection backrefs references
        mapM msg $ M.toList reused

    msg (name, id) = warn id 2318 $ "This assignment is used again in this '" ++ cmd ++ "', but won't have taken effect. Use two '" ++ cmd ++ "'s."

-    findReferences list = do
-        cfga <- asks cfgAnalysis
+    findReferences cfga list = do
        let graph = CF.graph cfga
        let nodesMap = CF.tokenToNodes cfga
        let nodes = S.unions $ map (\id -> M.findWithDefault S.empty id nodesMap) $ map getId $ list
--- a/src/ShellCheck/Checks/ControlFlow.hs
+++ b/src/ShellCheck/Checks/ControlFlow.hs
@ -78,7 +78,7 @@ controlFlowEffectChecks = [
 runNodeChecks :: [ControlFlowNodeCheck] -> ControlFlowCheck
 runNodeChecks perNode = do
    cfg <- asks cfgAnalysis
-    runOnAll cfg
+    mapM_ runOnAll cfg
  where
    getData datas n@(node, label) = do
        (pre, post) <- M.lookup node datas
--- a/src/ShellCheck/Checks/Custom.hs
+++ b/src/ShellCheck/Checks/Custom.hs
@ -1,7 +1,7 @@
 {-
    This empty file is provided for ease of patching in site specific checks.
    However, there are no guarantees regarding compatibility between versions.
-} 
+-}

 {-# LANGUAGE TemplateHaskell #-}
 module ShellCheck.Checks.Custom (checker, ShellCheck.Checks.Custom.runTests) where
--- a/src/ShellCheck/Checks/ShellSupport.hs
+++ b/src/ShellCheck/Checks/ShellSupport.hs
@ -19,6 +19,7 @@
 -}
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE ViewPatterns #-}
 module ShellCheck.Checks.ShellSupport (checker , ShellCheck.Checks.ShellSupport.runTests) where

 import ShellCheck.AST
@ -60,6 +61,9 @@ checks = [
    ,checkBraceExpansionVars
    ,checkMultiDimensionalArrays
    ,checkPS1Assignments
+    ,checkMultipleBangs
+    ,checkBangAfterPipe
+    ,checkNegatedUnaryOps
    ]

 testChecker (ForShell _ t) =
@ -73,22 +77,24 @@ verifyNot c s = producesComments (testChecker c) s == Just False
 prop_checkForDecimals1 = verify checkForDecimals "((3.14*c))"
 prop_checkForDecimals2 = verify checkForDecimals "foo[1.2]=bar"
 prop_checkForDecimals3 = verifyNot checkForDecimals "declare -A foo; foo[1.2]=bar"
-checkForDecimals = ForShell [Sh, Dash, Bash] f
+checkForDecimals = ForShell [Sh, Dash, BusyboxSh, Bash] f
  where
    f t@(TA_Expansion id _) = sequence_ $ do
-        str <- getLiteralString t
-        first <- str !!! 0
-        guard $ isDigit first && '.' `elem` str
+        first:rest <- getLiteralString t
+        guard $ isDigit first && '.' `elem` rest
        return $ err id 2079 "(( )) doesn't support decimals. Use bc or awk."
    f _ = return ()


 prop_checkBashisms = verify checkBashisms "while read a; do :; done < <(a)"
-prop_checkBashisms2 = verify checkBashisms "[ foo -nt bar ]"
+prop_checkBashisms2 = verifyNot checkBashisms "[ foo -nt bar ]"
 prop_checkBashisms3 = verify checkBashisms "echo $((i++))"
 prop_checkBashisms4 = verify checkBashisms "rm !(*.hs)"
 prop_checkBashisms5 = verify checkBashisms "source file"
 prop_checkBashisms6 = verify checkBashisms "[ \"$a\" == 42 ]"
+prop_checkBashisms6b = verify checkBashisms "test \"$a\" == 42"
+prop_checkBashisms6c = verify checkBashisms "[ foo =~ bar ]"
+prop_checkBashisms6d = verify checkBashisms "test foo =~ bar"
 prop_checkBashisms7 = verify checkBashisms "echo ${var[1]}"
 prop_checkBashisms8 = verify checkBashisms "echo ${!var[@]}"
 prop_checkBashisms9 = verify checkBashisms "echo ${!var*}"
@ -104,6 +110,7 @@ prop_checkBashisms18 = verify checkBashisms "foo &> /dev/null"
 prop_checkBashisms19 = verify checkBashisms "foo > file*.txt"
 prop_checkBashisms20 = verify checkBashisms "read -ra foo"
 prop_checkBashisms21 = verify checkBashisms "[ -a foo ]"
+prop_checkBashisms21b = verify checkBashisms "test -a foo"
 prop_checkBashisms22 = verifyNot checkBashisms "[ foo -a bar ]"
 prop_checkBashisms23 = verify checkBashisms "trap mything ERR INT"
 prop_checkBashisms24 = verifyNot checkBashisms "trap mything INT TERM"
@ -184,49 +191,82 @@ prop_checkBashisms96 = verifyNot checkBashisms "#!/bin/dash\necho $_"
 prop_checkBashisms97 = verify checkBashisms "#!/bin/sh\necho ${var,}"
 prop_checkBashisms98 = verify checkBashisms "#!/bin/sh\necho ${var^^}"
 prop_checkBashisms99 = verify checkBashisms "#!/bin/dash\necho [^f]oo"
-checkBashisms = ForShell [Sh, Dash] $ \t -> do
+prop_checkBashisms100 = verify checkBashisms "read -r"
+prop_checkBashisms101 = verify checkBashisms "read"
+prop_checkBashisms102 = verifyNot checkBashisms "read -r foo"
+prop_checkBashisms103 = verifyNot checkBashisms "read foo"
+prop_checkBashisms104 = verifyNot checkBashisms "read ''"
+prop_checkBashisms105 = verifyNot checkBashisms "#!/bin/busybox sh\nset -o pipefail"
+prop_checkBashisms106 = verifyNot checkBashisms "#!/bin/busybox sh\nx=x\n[[ \"$x\" = \"$x\" ]]"
+prop_checkBashisms107 = verifyNot checkBashisms "#!/bin/busybox sh\nx=x\n[ \"$x\" == \"$x\" ]"
+prop_checkBashisms108 = verifyNot checkBashisms "#!/bin/busybox sh\necho magic &> /dev/null"
+prop_checkBashisms109 = verifyNot checkBashisms "#!/bin/busybox sh\ntrap stop EXIT SIGTERM"
+prop_checkBashisms110 = verifyNot checkBashisms "#!/bin/busybox sh\nsource /dev/null"
+prop_checkBashisms111 = verify checkBashisms "#!/bin/dash\nx='test'\n${x:0:3}" -- SC3057
+prop_checkBashisms112 = verifyNot checkBashisms "#!/bin/busybox sh\nx='test'\n${x:0:3}" -- SC3057
+prop_checkBashisms113 = verify checkBashisms "#!/bin/dash\nx='test'\n${x/st/xt}" -- SC3060
+prop_checkBashisms114 = verifyNot checkBashisms "#!/bin/busybox sh\nx='test'\n${x/st/xt}" -- SC3060
+prop_checkBashisms115 = verify checkBashisms "#!/bin/busybox sh\nx='test'\n${!x}" -- SC3053
+prop_checkBashisms116 = verify checkBashisms "#!/bin/busybox sh\nx='test'\n${x[1]}" -- SC3054
+prop_checkBashisms117 = verify checkBashisms "#!/bin/busybox sh\nx='test'\n${!x[@]}" -- SC3055
+prop_checkBashisms118 = verify checkBashisms "#!/bin/busybox sh\nxyz=1\n${!x*}" -- SC3056
+prop_checkBashisms119 = verify checkBashisms "#!/bin/busybox sh\nx='test'\n${x^^[t]}" -- SC3059
+prop_checkBashisms120 = verify checkBashisms "#!/bin/sh\n[ x == y ]"
+prop_checkBashisms121 = verifyNot checkBashisms "#!/bin/sh\n# shellcheck shell=busybox\n[ x == y ]"
+prop_checkBashisms122 = verify checkBashisms "#!/bin/dash\n$'a'"
+prop_checkBashisms123 = verifyNot checkBashisms "#!/bin/busybox sh\n$'a'"
+prop_checkBashisms124 = verify checkBashisms "#!/bin/dash\ntype -p test"
+prop_checkBashisms125 = verifyNot checkBashisms "#!/bin/busybox sh\ntype -p test"
+prop_checkBashisms126 = verifyNot checkBashisms "#!/bin/busybox sh\nread -p foo -r bar"
+prop_checkBashisms127 = verifyNot checkBashisms "#!/bin/busybox sh\necho -ne foo"
+prop_checkBashisms128 = verify checkBashisms "#!/bin/dash\ntype -p test"
+prop_checkBashisms129 = verify checkBashisms "#!/bin/sh\n[ -k /tmp ]"
+prop_checkBashisms130 = verifyNot checkBashisms "#!/bin/dash\ntest -k /tmp"
+prop_checkBashisms131 = verify checkBashisms "#!/bin/sh\n[ -o errexit ]"
+checkBashisms = ForShell [Sh, Dash, BusyboxSh] $ \t -> do
    params <- ask
    kludge params t
 where
  -- This code was copy-pasted from Analytics where params was a variable
  kludge params = bashism
   where
-    isDash = shellType params == Dash
+    isBusyboxSh = shellType params == BusyboxSh
+    isDash = shellType params == Dash || isBusyboxSh
    warnMsg id code s =
        if isDash
        then err  id code $ "In dash, " ++ s ++ " not supported."
        else warn id code $ "In POSIX sh, " ++ s ++ " undefined."
+    asStr = getLiteralString

    bashism (T_ProcSub id _ _) = warnMsg id 3001 "process substitution is"
    bashism (T_Extglob id _ _) = warnMsg id 3002 "extglob is"
-    bashism (T_DollarSingleQuoted id _) = warnMsg id 3003 "$'..' is"
+    bashism (T_DollarSingleQuoted id _) =
+        unless isBusyboxSh $ warnMsg id 3003 "$'..' is"
    bashism (T_DollarDoubleQuoted id _) = warnMsg id 3004 "$\"..\" is"
    bashism (T_ForArithmetic id _ _ _ _) = warnMsg id 3005 "arithmetic for loops are"
    bashism (T_Arithmetic id _) = warnMsg id 3006 "standalone ((..)) is"
    bashism (T_DollarBracket id _) = warnMsg id 3007 "$[..] in place of $((..)) is"
    bashism (T_SelectIn id _ _ _) = warnMsg id 3008 "select loops are"
    bashism (T_BraceExpansion id _) = warnMsg id 3009 "brace expansion is"
-    bashism (T_Condition id DoubleBracket _) = warnMsg id 3010 "[[ ]] is"
+    bashism (T_Condition id DoubleBracket _) =
+        unless isBusyboxSh $ warnMsg id 3010 "[[ ]] is"
    bashism (T_HereString id _) = warnMsg id 3011 "here-strings are"
-    bashism (TC_Binary id SingleBracket op _ _)
-        | op `elem` [ "<", ">", "\\<", "\\>", "<=", ">=", "\\<=", "\\>="] =
-            unless isDash $ warnMsg id 3012 $ "lexicographical " ++ op ++ " is"
-    bashism (TC_Binary id SingleBracket op _ _)
-        | op `elem` [ "-ot", "-nt", "-ef" ] =
-            unless isDash $ warnMsg id 3013 $ op ++ " is"
-    bashism (TC_Binary id SingleBracket "==" _ _) =
-            warnMsg id 3014 "== in place of = is"
-    bashism (TC_Binary id SingleBracket "=~" _ _) =
-            warnMsg id 3015 "=~ regex matching is"
-    bashism (TC_Unary id SingleBracket "-v" _) =
-            warnMsg id 3016 "unary -v (in place of [ -n \"${var+x}\" ]) is"
-    bashism (TC_Unary id _ "-a" _) =
-            warnMsg id 3017 "unary -a in place of -e is"
+
+    bashism (TC_Binary id _ op _ _) =
+        checkTestOp bashismBinaryTestFlags op id
+    bashism (T_SimpleCommand id _ [asStr -> Just "test", lhs, asStr -> Just op, rhs]) =
+        checkTestOp bashismBinaryTestFlags op id
+    bashism (TC_Unary id _ op _) =
+        checkTestOp bashismUnaryTestFlags op id
+    bashism (T_SimpleCommand id _ [asStr -> Just "test", asStr -> Just op, _]) =
+        checkTestOp bashismUnaryTestFlags op id
+
    bashism (TA_Unary id op _)
        | op `elem` [ "|++", "|--", "++|", "--|"] =
            warnMsg id 3018 $ filter (/= '|') op ++ " is"
    bashism (TA_Binary id "**" _ _) = warnMsg id 3019 "exponentials are"
-    bashism (T_FdRedirect id "&" (T_IoFile _ (T_Greater _) _)) = warnMsg id 3020 "&> is"
+    bashism (T_FdRedirect id "&" (T_IoFile _ (T_Greater _) _)) =
+        unless isBusyboxSh $ warnMsg id 3020 "&> is"
    bashism (T_FdRedirect id "" (T_IoFile _ (T_GREATAND _) file)) =
        unless (all isDigit $ onlyLiteralString file) $ warnMsg id 3021 ">& filename (as opposed to >& fd) is"
    bashism (T_FdRedirect id ('{':_) _) = warnMsg id 3022 "named file descriptors are"
@ -246,7 +286,8 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
        warnMsg id 3028 $ str ++ " is"

    bashism t@(T_DollarBraced id _ token) = do
-        mapM_ check expansion
+        unless isBusyboxSh $ mapM_ check simpleExpansions
+        mapM_ check advancedExpansions
        when (isBashVariable var) $
            warnMsg id 3028 $ var ++ " is"
      where
@ -274,7 +315,11 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do

    bashism t@(T_SimpleCommand _ _ (cmd:arg:_))
        | t `isCommand` "echo" && argString `matches` flagRegex =
-            if isDash
+            if isBusyboxSh
+            then
+                unless (argString `matches` busyboxFlagRegex) $
+                    warnMsg (getId arg) 3036 "echo flags besides -n and -e"
+            else if isDash
            then
                when (argString /= "-n") $
                    warnMsg (getId arg) 3036 "echo flags besides -n"
@ -283,6 +328,7 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
      where
          argString = concat $ oversimplify arg
          flagRegex = mkRegex "^-[eEsn]+$"
+          busyboxFlagRegex = mkRegex "^-[en]+$"

    bashism t@(T_SimpleCommand _ _ (cmd:arg:_))
        | getLiteralString cmd == Just "exec" && "-" `isPrefixOf` concat (oversimplify arg) =
@ -356,7 +402,8 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
                    (\x -> (not . null . snd $ x) && snd x `notElem` allowed) flags
                return . warnMsg (getId word) 3045 $ name ++ " -" ++ flag ++ " is"

-            when (name == "source") $ warnMsg id 3046 "'source' in place of '.' is"
+            when (name == "source" && not isBusyboxSh) $
+                warnMsg id 3046 "'source' in place of '.' is"
            when (name == "trap") $
                let
                    check token = sequence_ $ do
@ -365,7 +412,7 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
                        return $ do
                            when (upper `elem` ["ERR", "DEBUG", "RETURN"]) $
                                warnMsg (getId token) 3047 $ "trapping " ++ str ++ " is"
-                            when ("SIG" `isPrefixOf` upper) $
+                            when (not isBusyboxSh && "SIG" `isPrefixOf` upper) $
                                warnMsg (getId token) 3048
                                    "prefixing signal names with 'SIG' is"
                            when (not isDash && upper /= str) $
@ -379,6 +426,9 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
                let literal = onlyLiteralString format
                guard $ "%q" `isInfixOf` literal
                return $ warnMsg (getId format) 3050 "printf %q is"
+
+            when (name == "read" && all isFlag rest) $
+                warnMsg (getId cmd) 3061 "read without a variable is"
      where
        unsupportedCommands = [
            "let", "caller", "builtin", "complete", "compgen", "declare", "dirs", "disown",
@ -392,17 +442,19 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
            ("hash", Just $ if isDash then ["r", "v"] else ["r"]),
            ("jobs", Just ["l", "p"]),
            ("printf", Just []),
-            ("read", Just $ if isDash then ["r", "p"] else ["r"]),
+            ("read", Just $ if isDash || isBusyboxSh then ["r", "p"] else ["r"]),
            ("readonly", Just ["p"]),
            ("trap", Just []),
-            ("type", Just []),
+            ("type", Just $ if isBusyboxSh then ["p"] else []),
            ("ulimit", if isDash then Nothing else Just ["f"]),
            ("umask", Just ["S"]),
            ("unset", Just ["f", "v"]),
            ("wait", Just [])
            ]
    bashism t@(T_SourceCommand id src _)
-        | getCommandName src == Just "source" = warnMsg id 3051 "'source' in place of '.' is"
+      | getCommandName src == Just "source" =
+          unless isBusyboxSh $
+            warnMsg id 3051 "'source' in place of '.' is"
    bashism (TA_Expansion _ (T_Literal id str : _))
        | str `matches` radix = warnMsg id 3052 "arithmetic base conversion is"
      where
@ -410,14 +462,16 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
    bashism _ = return ()

    varChars="_0-9a-zA-Z"
-    expansion = let re = mkRegex in [
+    advancedExpansions = let re = mkRegex in [
        (re $ "^![" ++ varChars ++ "]", 3053, "indirect expansion is"),
        (re $ "^[" ++ varChars ++ "]+\\[.*\\]$", 3054, "array references are"),
        (re $ "^![" ++ varChars ++ "]+\\[[*@]]$", 3055, "array key expansion is"),
        (re $ "^![" ++ varChars ++ "]+[*@]$", 3056, "name matching prefixes are"),
+        (re $ "^[" ++ varChars ++ "*@]+(\\[.*\\])?[,^]", 3059, "case modification is")
+        ]
+    simpleExpansions = let re = mkRegex in [
        (re $ "^[" ++ varChars ++ "*@]+:[^-=?+]", 3057, "string indexing is"),
        (re $ "^([*@][%#]|#[@*])", 3058, "string operations on $@/$* are"),
-        (re $ "^[" ++ varChars ++ "*@]+(\\[.*\\])?[,^]", 3059, "case modification is"),
        (re $ "^[" ++ varChars ++ "*@]+(\\[.*\\])?/", 3060, "string replacement is")
        ]
    bashVars = [
@ -443,6 +497,50 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
                Assignment (_, _, name, _) -> name == var
                _ -> False

+    checkTestOp table op id = sequence_ $ do
+        (code, shells, msg) <- Map.lookup op table
+        guard . not $ shellType params `elem` shells
+        return $ warnMsg id code (msg op)
+
+
+buildTestFlagMap list = Map.fromList $ concatMap (\(x,y) -> map (\c -> (c,y)) x) list
+bashismBinaryTestFlags = buildTestFlagMap [
+    -- ([list of applicable flags],
+    --     (error code, exempt shells, message builder :: String -> String)),
+    --
+    -- Distinct error codes allow the wiki to give more helpful, targeted
+    -- information.
+    (["<", ">", "\\<", "\\>", "<=", ">=", "\\<=", "\\>="],
+        (3012, [Dash, BusyboxSh], \op -> "lexicographical " ++ op ++ " is")),
+    (["=="],
+        (3014, [BusyboxSh], \op -> op ++ " in place of = is")),
+    (["=~"],
+        (3015, [], \op -> op ++ " regex matching is")),
+
+    ([], (0,[],const ""))
+  ]
+bashismUnaryTestFlags = buildTestFlagMap [
+    (["-v"],
+        (3016, [], \op -> "test " ++ op ++ " (in place of [ -n \"${var+x}\" ]) is")),
+    (["-a"],
+        (3017, [], \op -> "unary " ++ op ++ " in place of -e is")),
+    (["-o"],
+        (3062, [], \op -> "test " ++ op ++ " to check options is")),
+    (["-R"],
+        (3063, [], \op -> "test " ++ op ++ " and namerefs in general are")),
+    (["-N"],
+        (3064, [], \op -> "test " ++ op ++ " is")),
+    (["-k"],
+        (3065, [Dash, BusyboxSh], \op -> "test " ++ op ++ " is")),
+    (["-G"],
+        (3066, [Dash, BusyboxSh], \op -> "test " ++ op ++ " is")),
+    (["-O"],
+        (3067, [Dash, BusyboxSh], \op -> "test " ++ op ++ " is")),
+
+    ([], (0,[],const ""))
+  ]
+
+
 prop_checkEchoSed1 = verify checkEchoSed "FOO=$(echo \"$cow\" | sed 's/foo/bar/g')"
 prop_checkEchoSed1b = verify checkEchoSed "FOO=$(sed 's/foo/bar/g' <<< \"$cow\")"
 prop_checkEchoSed2 = verify checkEchoSed "rm $(echo $cow | sed -e 's,foo,bar,')"
@ -558,5 +656,46 @@ checkPS1Assignments = ForShell [Bash] f
    escapeRegex = mkRegex "\\\\x1[Bb]|\\\\e|\x1B|\\\\033"


+prop_checkMultipleBangs1 = verify checkMultipleBangs "! ! true"
+prop_checkMultipleBangs2 = verifyNot checkMultipleBangs "! true"
+checkMultipleBangs = ForShell [Dash, BusyboxSh, Sh] f
+  where
+    f token = case token of
+        T_Banged id (T_Banged _ _) ->
+            err id 2325 "Multiple ! in front of pipelines are a bash/ksh extension. Use only 0 or 1."
+        _ -> return ()
+
+
+prop_checkBangAfterPipe1 = verify checkBangAfterPipe "true | ! true"
+prop_checkBangAfterPipe2 = verifyNot checkBangAfterPipe "true | ( ! true )"
+prop_checkBangAfterPipe3 = verifyNot checkBangAfterPipe "! ! true | true"
+checkBangAfterPipe = ForShell [Dash, BusyboxSh, Sh, Bash] f
+  where
+    f token = case token of
+        T_Pipeline _ _ cmds -> mapM_ check cmds
+        _ -> return ()
+
+    check token = case token of
+        T_Banged id _ ->
+            err id 2326 "! is not allowed in the middle of pipelines. Use command group as in cmd | { ! cmd; } if necessary."
+        _ -> return ()
+
+
+prop_checkNegatedUnaryOps1 = verify checkNegatedUnaryOps "[ ! -o braceexpand ]"
+prop_checkNegatedUnaryOps2 = verifyNot checkNegatedUnaryOps "[ -o braceexpand ]"
+prop_checkNegatedUnaryOps3 = verifyNot checkNegatedUnaryOps "[[ ! -o braceexpand ]]"
+prop_checkNegatedUnaryOps4 = verifyNot checkNegatedUnaryOps "! [ -o braceexpand ]"
+prop_checkNegatedUnaryOps5 = verify checkNegatedUnaryOps "[ ! -a file ]"
+checkNegatedUnaryOps = ForShell [Bash] f
+  where
+    f token = case token of
+        TC_Unary id SingleBracket "!" (TC_Unary _ _ op _) | op `elem` ["-a", "-o"] ->
+            err id 2332 $ msg op
+        _ -> return ()
+
+    msg "-o" = "[ ! -o opt ] is always true because -o becomes logical OR. Use [[ ]] or ! [ -o opt ]."
+    msg "-a" = "[ ! -a file ] is always true because -a becomes logical AND. Use -e instead."
+    msg _ = pleaseReport "unhandled negated unary message"
+
 return []
 runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])
--- a/src/ShellCheck/Data.hs
+++ b/src/ShellCheck/Data.hs
@ -49,6 +49,7 @@ internalVariables = [
    "LINES", "MAIL", "MAILCHECK", "MAILPATH", "OPTERR", "PATH",
    "POSIXLY_CORRECT", "PROMPT_COMMAND", "PROMPT_DIRTRIM", "PS0", "PS1",
    "PS2", "PS3", "PS4", "SHELL", "TIMEFORMAT", "TMOUT", "TMPDIR",
+    "BASH_MONOSECONDS", "BASH_TRAPSIG", "GLOBSORT",
    "auto_resume", "histchars",

    -- Other
@ -62,6 +63,9 @@ internalVariables = [
    , "FLAGS_ARGC", "FLAGS_ARGV", "FLAGS_ERROR", "FLAGS_FALSE", "FLAGS_HELP",
    "FLAGS_PARENT", "FLAGS_RESERVED", "FLAGS_TRUE", "FLAGS_VERSION",
    "flags_error", "flags_return"
+
+    -- Bats
+    ,"stderr", "stderr_lines"
  ]

 specialIntegerVariables = [
@ -75,7 +79,7 @@ variablesWithoutSpaces = specialVariablesWithoutSpaces ++ [
    "EPOCHREALTIME", "EPOCHSECONDS", "LINENO", "OPTIND", "PPID", "RANDOM",
    "READLINE_ARGUMENT", "READLINE_MARK", "READLINE_POINT", "SECONDS",
    "SHELLOPTS", "SHLVL", "SRANDOM", "UID", "COLUMNS", "HISTFILESIZE",
-    "HISTSIZE", "LINES"
+    "HISTSIZE", "LINES", "BASH_MONOSECONDS", "BASH_TRAPSIG"

    -- shflags
    , "FLAGS_ERROR", "FLAGS_FALSE", "FLAGS_TRUE"
@ -156,11 +160,15 @@ shellForExecutable name =
        "sh"    -> return Sh
        "bash"  -> return Bash
        "bats"  -> return Bash
+        "busybox"  -> return BusyboxSh -- Used for directives and --shell=busybox
+        "busybox sh"  -> return BusyboxSh
+        "busybox ash"  -> return BusyboxSh
        "dash"  -> return Dash
        "ash"   -> return Dash -- There's also a warning for this.
        "ksh"   -> return Ksh
        "ksh88" -> return Ksh
        "ksh93" -> return Ksh
+        "oksh"  -> return Ksh
        _ -> Nothing

 flagsForRead = "sreu:n:N:i:p:a:t:"
--- a/src/ShellCheck/Formatter/CheckStyle.hs
+++ b/src/ShellCheck/Formatter/CheckStyle.hs
@ -24,8 +24,8 @@ import ShellCheck.Formatter.Format

 import Data.Char
 import Data.List
-import GHC.Exts
 import System.IO
+import qualified Data.List.NonEmpty as NE

 format :: IO Formatter
 format = return Formatter {
@ -45,12 +45,12 @@ outputResults cr sys =
    else mapM_ outputGroup fileGroups
  where
    comments = crComments cr
-    fileGroups = groupWith sourceFile comments
+    fileGroups = NE.groupWith sourceFile comments
    outputGroup group = do
-        let filename = sourceFile (head group)
+        let filename = sourceFile (NE.head group)
        result <- siReadFile sys (Just True) filename
        let contents = either (const "") id result
-        outputFile filename contents group
+        outputFile filename contents (NE.toList group)

 outputFile filename contents warnings = do
    let comments = makeNonVirtual warnings contents
--- a/src/ShellCheck/Formatter/GCC.hs
+++ b/src/ShellCheck/Formatter/GCC.hs
@ -23,8 +23,8 @@ import ShellCheck.Interface
 import ShellCheck.Formatter.Format

 import Data.List
-import GHC.Exts
 import System.IO
+import qualified Data.List.NonEmpty as NE

 format :: IO Formatter
 format = return Formatter {
@ -39,13 +39,13 @@ outputError file error = hPutStrLn stderr $ file ++ ": " ++ error
 outputAll cr sys = mapM_ f groups
  where
    comments = crComments cr
-    groups = groupWith sourceFile comments
-    f :: [PositionedComment] -> IO ()
+    groups = NE.groupWith sourceFile comments
+    f :: NE.NonEmpty PositionedComment -> IO ()
    f group = do
-        let filename = sourceFile (head group)
+        let filename = sourceFile (NE.head group)
        result <- siReadFile sys (Just True) filename
        let contents = either (const "") id result
-        outputResult filename contents group
+        outputResult filename contents (NE.toList group)

 outputResult filename contents warnings = do
    let comments = makeNonVirtual warnings contents
--- a/src/ShellCheck/Formatter/JSON1.hs
+++ b/src/ShellCheck/Formatter/JSON1.hs
@ -27,9 +27,9 @@ import Control.DeepSeq
 import Data.Aeson
 import Data.IORef
 import Data.Monoid
-import GHC.Exts
 import System.IO
 import qualified Data.ByteString.Lazy.Char8 as BL
+import qualified Data.List.NonEmpty as NE

 format :: IO Formatter
 format = do
@ -114,10 +114,10 @@ outputError file msg = hPutStrLn stderr $ file ++ ": " ++ msg
 collectResult ref cr sys = mapM_ f groups
  where
    comments = crComments cr
-    groups = groupWith sourceFile comments
-    f :: [PositionedComment] -> IO ()
+    groups = NE.groupWith sourceFile comments
+    f :: NE.NonEmpty PositionedComment -> IO ()
    f group = do
-        let filename = sourceFile (head group)
+        let filename = sourceFile (NE.head group)
        result <- siReadFile sys (Just True) filename
        let contents = either (const "") id result
        let comments' = makeNonVirtual comments contents
--- a/src/ShellCheck/Formatter/TTY.hs
+++ b/src/ShellCheck/Formatter/TTY.hs
@ -31,9 +31,9 @@ import Data.Ord
 import Data.IORef
 import Data.List
 import Data.Maybe
-import GHC.Exts
 import System.IO
 import System.Info
+import qualified Data.List.NonEmpty as NE

 wikiLink = "https://www.shellcheck.net/wiki/"

@ -117,19 +117,19 @@ outputResult options ref result sys = do
    color <- getColorFunc $ foColorOption options
    let comments = crComments result
    appendComments ref comments (fromIntegral $ foWikiLinkCount options)
-    let fileGroups = groupWith sourceFile comments
+    let fileGroups = NE.groupWith sourceFile comments
    mapM_ (outputForFile color sys) fileGroups

 outputForFile color sys comments = do
-    let fileName = sourceFile (head comments)
+    let fileName = sourceFile (NE.head comments)
    result <- siReadFile sys (Just True) fileName
    let contents = either (const "") id result
    let fileLinesList = lines contents
    let lineCount = length fileLinesList
    let fileLines = listArray (1, lineCount) fileLinesList
-    let groups = groupWith lineNo comments
+    let groups = NE.groupWith lineNo comments
    forM_ groups $ \commentsForLine -> do
-        let lineNum = fromIntegral $ lineNo (head commentsForLine)
+        let lineNum = fromIntegral $ lineNo (NE.head commentsForLine)
        let line = if lineNum < 1 || lineNum > lineCount
                        then ""
                        else fileLines ! fromIntegral lineNum
@ -139,7 +139,7 @@ outputForFile color sys comments = do
        putStrLn (color "source" line)
        forM_ commentsForLine $ \c -> putStrLn $ color (severityText c) $ cuteIndent c
        putStrLn ""
-        showFixedString color commentsForLine (fromIntegral lineNum) fileLines
+        showFixedString color (toList commentsForLine) (fromIntegral lineNum) fileLines

 -- Pick out only the lines necessary to show a fix in action
 sliceFile :: Fix -> Array Int String -> (Fix, Array Int String)
@ -169,7 +169,7 @@ showFixedString color comments lineNum fileLines =
            -- and/or other unrelated lines.
            let (excerptFix, excerpt) = sliceFile mergedFix fileLines
            -- in the spirit of error prone
-            putStrLn $ color "message" "Did you mean: "
+            putStrLn $ color "message" "Did you mean:"
            putStrLn $ unlines $ applyFix excerptFix excerpt

 cuteIndent :: PositionedComment -> String
--- a/src/ShellCheck/Interface.hs
+++ b/src/ShellCheck/Interface.hs
@ -1,5 +1,5 @@
 {-
-    Copyright 2012-2019 Vidar Holen
+    Copyright 2012-2024 Vidar Holen

    This file is part of ShellCheck.
    https://www.shellcheck.net
@ -21,14 +21,14 @@
 module ShellCheck.Interface
    (
    SystemInterface(..)
-    , CheckSpec(csFilename, csScript, csCheckSourced, csIncludedWarnings, csExcludedWarnings, csShellTypeOverride, csMinSeverity, csIgnoreRC, csOptionalChecks)
+    , CheckSpec(csFilename, csScript, csCheckSourced, csIncludedWarnings, csExcludedWarnings, csShellTypeOverride, csMinSeverity, csIgnoreRC, csExtendedAnalysis, csOptionalChecks)
    , CheckResult(crFilename, crComments)
    , ParseSpec(psFilename, psScript, psCheckSourced, psIgnoreRC, psShellTypeOverride)
    , ParseResult(prComments, prTokenPositions, prRoot)
-    , AnalysisSpec(asScript, asShellType, asFallbackShell, asExecutionMode, asCheckSourced, asTokenPositions, asOptionalChecks)
+    , AnalysisSpec(asScript, asShellType, asFallbackShell, asExecutionMode, asCheckSourced, asTokenPositions, asExtendedAnalysis, asOptionalChecks)
    , AnalysisResult(arComments)
    , FormatterOptions(foColorOption, foWikiLinkCount)
-    , Shell(Ksh, Sh, Bash, Dash)
+    , Shell(Ksh, Sh, Bash, Dash, BusyboxSh)
    , ExecutionMode(Executed, Sourced)
    , ErrorMessage
    , Code
@ -39,11 +39,12 @@ module ShellCheck.Interface
    , ColorOption(ColorAuto, ColorAlways, ColorNever)
    , TokenComment(tcId, tcComment, tcFix)
    , emptyCheckResult
-    , newParseResult
-    , newAnalysisSpec
    , newAnalysisResult
+    , newAnalysisSpec
    , newFormatterOptions
+    , newParseResult
    , newPosition
+    , newSystemInterface
    , newTokenComment
    , mockedSystemInterface
    , mockRcFile
@ -99,6 +100,7 @@ data CheckSpec = CheckSpec {
    csIncludedWarnings :: Maybe [Integer],
    csShellTypeOverride :: Maybe Shell,
    csMinSeverity :: Severity,
+    csExtendedAnalysis :: Maybe Bool,
    csOptionalChecks :: [String]
 } deriving (Show, Eq)

@ -123,6 +125,7 @@ emptyCheckSpec = CheckSpec {
    csIncludedWarnings = Nothing,
    csShellTypeOverride = Nothing,
    csMinSeverity = StyleC,
+    csExtendedAnalysis = Nothing,
    csOptionalChecks = []
 }

@ -135,6 +138,14 @@ newParseSpec = ParseSpec {
    psShellTypeOverride = Nothing
 }

+newSystemInterface :: Monad m => SystemInterface m
+newSystemInterface =
+    SystemInterface {
+        siReadFile = \_ _ -> return $ Left "Not implemented",
+        siFindSource = \_ _ _ name -> return name,
+        siGetConfig = \_ -> return Nothing
+    }
+
 -- Parser input and output
 data ParseSpec = ParseSpec {
    psFilename :: String,
@ -165,6 +176,7 @@ data AnalysisSpec = AnalysisSpec {
    asExecutionMode :: ExecutionMode,
    asCheckSourced :: Bool,
    asOptionalChecks :: [String],
+    asExtendedAnalysis :: Maybe Bool,
    asTokenPositions :: Map.Map Id (Position, Position)
 }

@ -175,6 +187,7 @@ newAnalysisSpec token = AnalysisSpec {
    asExecutionMode = Executed,
    asCheckSourced = False,
    asOptionalChecks = [],
+    asExtendedAnalysis = Nothing,
    asTokenPositions = Map.empty
 }

@ -212,7 +225,7 @@ newCheckDescription = CheckDescription {
    }

 -- Supporting data types
-data Shell = Ksh | Sh | Bash | Dash deriving (Show, Eq)
+data Shell = Ksh | Sh | Bash | Dash | BusyboxSh deriving (Show, Eq)
 data ExecutionMode = Executed | Sourced deriving (Show, Eq)

 type ErrorMessage = String
@ -311,7 +324,7 @@ data ColorOption =

 -- For testing
 mockedSystemInterface :: [(String, String)] -> SystemInterface Identity
-mockedSystemInterface files = SystemInterface {
+mockedSystemInterface files = (newSystemInterface :: SystemInterface Identity) {
    siReadFile = rf,
    siFindSource = fs,
    siGetConfig = const $ return Nothing
@ -326,4 +339,3 @@ mockedSystemInterface files = SystemInterface {
 mockRcFile rcfile mock = mock {
    siGetConfig = const . return $ Just (".shellcheckrc", rcfile)
 }
-
--- a/src/ShellCheck/Parser.hs
+++ b/src/ShellCheck/Parser.hs
@ -46,6 +46,7 @@ import Text.Parsec.Error
 import Text.Parsec.Pos
 import qualified Control.Monad.Reader as Mr
 import qualified Control.Monad.State as Ms
+import qualified Data.List.NonEmpty as NE
 import qualified Data.Map.Strict as Map

 import Test.QuickCheck.All (quickCheckAll)
@ -140,15 +141,9 @@ carriageReturn = do
    parseProblemAt pos ErrorC 1017 "Literal carriage return. Run script through tr -d '\\r' ."
    return '\r'

-almostSpace =
-    choice [
-        check '\xA0' "unicode non-breaking space",
-        check '\x200B' "unicode zerowidth space"
-    ]
-  where
-    check c name = do
-        parseNote ErrorC 1018 $ "This is a " ++ name ++ ". Delete and retype it."
-        char c
+almostSpace = do
+        parseNote ErrorC 1018 $ "This is a unicode space. Delete and retype it."
+        oneOf "\xA0\x2002\x2003\x2004\x2005\x2006\x2007\x2008\x2009\x200B\x202F"
        return ' '

 --------- Message/position annotation on top of user state
@ -160,7 +155,7 @@ data Context =
    deriving (Show)

 data HereDocContext =
-        HereDocPending Token [Context] -- on linefeed, read this T_HereDoc
+        HereDocPending Id Dashed Quoted String [Context] -- on linefeed, read this T_HereDoc
    deriving (Show)

 data UserState = UserState {
@ -238,12 +233,12 @@ addToHereDocMap id list = do
        hereDocMap = Map.insert id list map
    }

-addPendingHereDoc t = do
+addPendingHereDoc id d q str = do
    state <- getState
    context <- getCurrentContexts
    let docs = pendingHereDocs state
    putState $ state {
-        pendingHereDocs = HereDocPending t context : docs
+        pendingHereDocs = HereDocPending id d q str context : docs
    }

 popPendingHereDocs = do
@ -826,7 +821,7 @@ readArithmeticContents =
        char ')'
        id <- endSpan start
        spacing
-        return $ TA_Parentesis id s
+        return $ TA_Parenthesis id s

    readArithTerm = readGroup <|> readVariable <|> readExpansion

@ -1057,6 +1052,16 @@ readAnnotationWithoutPrefix sandboxed = do
                        "This shell type is unknown. Use e.g. sh or bash."
                return [ShellOverride shell]

+            "extended-analysis" -> do
+                pos <- getPosition
+                value <- plainOrQuoted $ many1 letter
+                case value of
+                    "true" -> return [ExtendedAnalysis True]
+                    "false" -> return [ExtendedAnalysis False]
+                    _ -> do
+                        parseNoteAt pos ErrorC 1146 "Unknown extended-analysis value. Expected true/false."
+                        return []
+
            "external-sources" -> do
                pos <- getPosition
                value <- plainOrQuoted $ many1 letter
@ -1194,7 +1199,7 @@ readDollarBracedPart = readSingleQuoted <|> readDoubleQuoted <|>

 readDollarBracedLiteral = do
    start <- startSpan
-    vars <- (readBraceEscaped <|> (anyChar >>= \x -> return [x])) `reluctantlyTill1` bracedQuotable
+    vars <- (readBraceEscaped <|> ((\x -> [x]) <$> anyChar)) `reluctantlyTill1` bracedQuotable
    id <- endSpan start
    return $ T_Literal id $ concat vars

@ -1556,7 +1561,7 @@ readGenericLiteral endChars = do
    return $ concat strings

 readGenericLiteral1 endExp = do
-    strings <- (readGenericEscaped <|> (anyChar >>= \x -> return [x])) `reluctantlyTill1` endExp
+    strings <- (readGenericEscaped <|> ((\x -> [x]) <$> anyChar)) `reluctantlyTill1` endExp
    return $ concat strings

 readGenericEscaped = do
@ -1835,7 +1840,7 @@ readHereDoc = called "here document" $ do

    -- add empty tokens for now, read the rest in readPendingHereDocs
    let doc = T_HereDoc hid dashed quoted endToken []
-    addPendingHereDoc doc
+    addPendingHereDoc hid dashed quoted endToken
    return doc
  where
    unquote :: String -> (Quoted, String)
@ -1856,7 +1861,7 @@ readPendingHereDocs = do
    docs <- popPendingHereDocs
    mapM_ readDoc docs
  where
-    readDoc (HereDocPending (T_HereDoc id dashed quoted endToken _) ctx) =
+    readDoc (HereDocPending id dashed quoted endToken ctx) =
      swapContext ctx $
      do
        docStartPos <- getPosition
@ -2283,22 +2288,31 @@ readSource t@(T_Redirecting _ _ (T_SimpleCommand cmdId _ (cmd:file':rest'))) = d

    subRead name script =
        withContext (ContextSource name) $
-            inSeparateContext $
-                subParse (initialPos name) (readScriptFile True) script
+            inSeparateContext $ do
+                oldState <- getState
+                setState $ oldState { pendingHereDocs = [] }
+                result <- subParse (initialPos name) (readScriptFile True) script
+                newState <- getState
+                setState $ newState { pendingHereDocs = pendingHereDocs oldState }
+                return result
 readSource t = return t


 prop_readPipeline = isOk readPipeline "! cat /etc/issue | grep -i ubuntu"
 prop_readPipeline2 = isWarning readPipeline "!cat /etc/issue | grep -i ubuntu"
 prop_readPipeline3 = isOk readPipeline "for f; do :; done|cat"
+prop_readPipeline4 = isOk readPipeline "! ! true"
+prop_readPipeline5 = isOk readPipeline "true | ! true"
 readPipeline = do
    unexpecting "keyword/token" readKeyword
-    do
-        (T_Bang id) <- g_Bang
-        pipe <- readPipeSequence
-        return $ T_Banged id pipe
-      <|>
-        readPipeSequence
+    readBanged readPipeSequence
+
+readBanged parser = do
+    pos <- getPosition
+    (T_Bang id) <- g_Bang
+    next <- readBanged parser
+    return $ T_Banged id next
+ <|> parser

 prop_readAndOr = isOk readAndOr "grep -i lol foo || exit 1"
 prop_readAndOr1 = isOk readAndOr "# shellcheck disable=1\nfoo"
@ -2354,14 +2368,14 @@ readTerm = do

 readPipeSequence = do
    start <- startSpan
-    (cmds, pipes) <- sepBy1WithSeparators readCommand
+    (cmds, pipes) <- sepBy1WithSeparators (readBanged readCommand)
                        (readPipe `thenSkip` (spacing >> readLineBreak))
    id <- endSpan start
    spacing
    return $ T_Pipeline id pipes cmds
  where
    sepBy1WithSeparators p s = do
-        let elems = p >>= \x -> return ([x], [])
+        let elems = (\x -> ([x], [])) <$> p
        let seps = do
            separator <- s
            return $ \(a,b) (c,d) -> (a++c, b ++ d ++ [separator])
@ -2384,6 +2398,10 @@ readCommand = choice [
    ]

 readCmdName = do
+    -- If the command name is `!` then
+    optional . lookAhead . try $ do
+        char '!'
+        whitespace
    -- Ignore alias suppression
    optional . try $ do
        char '\\'
@ -2777,17 +2795,29 @@ readFunctionDefinition = called "function" $ do
 prop_readCoProc1 = isOk readCoProc "coproc foo { echo bar; }"
 prop_readCoProc2 = isOk readCoProc "coproc { echo bar; }"
 prop_readCoProc3 = isOk readCoProc "coproc echo bar"
+prop_readCoProc4 = isOk readCoProc "coproc a=b echo bar"
+prop_readCoProc5 = isOk readCoProc "coproc 'foo' { echo bar; }"
+prop_readCoProc6 = isOk readCoProc "coproc \"foo$$\" { echo bar; }"
+prop_readCoProc7 = isOk readCoProc "coproc 'foo' ( echo bar )"
+prop_readCoProc8 = isOk readCoProc "coproc \"foo$$\" while true; do true; done"
 readCoProc = called "coproc" $ do
    start <- startSpan
    try $ do
        string "coproc"
-        whitespace
+        spacing1
    choice [ try $ readCompoundCoProc start, readSimpleCoProc start ]
  where
    readCompoundCoProc start = do
-        var <- optionMaybe $
-            readVariableName `thenSkip` whitespace
-        body <- readBody readCompoundCommand
+        notFollowedBy2 readAssignmentWord
+        (var, body) <- choice [
+            try $ do
+                body <- readBody readCompoundCommand
+                return (Nothing, body),
+            try $ do
+                var <- readNormalWord `thenSkip` spacing
+                body <- readBody readCompoundCommand
+                return (Just var, body)
+            ]
        id <- endSpan start
        return $ T_CoProc id var body
    readSimpleCoProc start = do
@ -2891,8 +2921,8 @@ readLetSuffix = many1 (readIoRedirect <|> try readLetExpression <|> readCmdWord)
    kludgeAwayQuotes :: String -> SourcePos -> (String, SourcePos)
    kludgeAwayQuotes s p =
        case s of
-            first:rest@(_:_) ->
-                let (last:backwards) = reverse rest
+            first:second:rest ->
+                let (last NE.:| backwards) = NE.reverse (second NE.:| rest)
                    middle = reverse backwards
                in
                    if first `elem` "'\"" && first == last
@ -3322,10 +3352,12 @@ readScriptFile sourced = do
              then do
                    commands <- readCompoundListOrEmpty
                    id <- endSpan start
+                    readPendingHereDocs
                    verifyEof
                    let script = T_Annotation annotationId annotations $
                                    T_Script id shebang commands
-                    reparseIndices script
+                    userstate <- getState
+                    reparseIndices $ reattachHereDocs script (hereDocMap userstate)
                else do
                    many anyChar
                    id <- endSpan start
@ -3335,8 +3367,8 @@ readScriptFile sourced = do
    verifyShebang pos s = do
        case isValidShell s of
            Just True -> return ()
-            Just False -> parseProblemAt pos ErrorC 1071 "ShellCheck only supports sh/bash/dash/ksh scripts. Sorry!"
-            Nothing -> parseProblemAt pos ErrorC 1008 "This shebang was unrecognized. ShellCheck only supports sh/bash/dash/ksh. Add a 'shell' directive to specify."
+            Just False -> parseProblemAt pos ErrorC 1071 "ShellCheck only supports sh/bash/dash/ksh/'busybox sh' scripts. Sorry!"
+            Nothing -> parseProblemAt pos ErrorC 1008 "This shebang was unrecognized. ShellCheck only supports sh/bash/dash/ksh/'busybox sh'. Add a 'shell' directive to specify."

    isValidShell s =
        let good = null s || any (`isPrefixOf` s) goodShells
@ -3352,16 +3384,20 @@ readScriptFile sourced = do
        "sh",
        "ash",
        "dash",
+        "busybox sh",
        "bash",
        "bats",
-        "ksh"
+        "ksh",
+        "oksh"
        ]
    badShells = [
        "awk",
        "csh",
        "expect",
+        "fish",
        "perl",
        "python",
+        "python3",
        "ruby",
        "tcsh",
        "zsh"
@ -3414,13 +3450,22 @@ isOk p s =      parsesCleanly p s == Just True   -- The string parses with no wa
 isWarning p s = parsesCleanly p s == Just False  -- The string parses with warnings
 isNotOk p s =   parsesCleanly p s == Nothing     -- The string does not parse

-parsesCleanly parser string = runIdentity $ do
-    (res, sys) <- runParser testEnvironment
-                    (parser >> eof >> getState) "-" string
-    case (res, sys) of
-        (Right userState, systemState) ->
-            return $ Just . null $ parseNotes userState ++ parseProblems systemState
-        (Left _, _) -> return Nothing
+-- If the parser matches the string, return Right [ParseNotes+ParseProblems]
+-- If it does not match the string,  return Left  [ParseProblems]
+getParseOutput parser string = runIdentity $ do
+    (res, systemState) <- runParser testEnvironment
+                            (parser >> eof >> getState) "-" string
+    return $ case res of
+        Right userState ->
+            Right $ parseNotes userState ++ parseProblems systemState
+        Left _ -> Left $ parseProblems systemState
+
+-- If the parser matches the string, return Just whether it was clean (without emitting suggestions)
+-- Otherwise, Nothing
+parsesCleanly parser string =
+    case getParseOutput parser string of
+        Right list -> Just $ null list
+        Left _ -> Nothing

 parseWithNotes parser = do
    item <- parser
@ -3438,9 +3483,8 @@ makeErrorFor parsecError =
      pos = errorPos parsecError

 getStringFromParsec errors =
-        case map f errors of
-            r -> unwords (take 1 $ catMaybes $ reverse r)  ++
-                " Fix any mentioned problems and try again."
+        headOrDefault "" (mapMaybe f $ reverse errors)  ++
+            " Fix any mentioned problems and try again."
    where
        f err =
            case err of
@ -3471,8 +3515,7 @@ parseShell env name contents = do
            return newParseResult {
                prComments = map toPositionedComment $ nub $ parseNotes userstate ++ parseProblems state,
                prTokenPositions = Map.map startEndPosToPos (positionMap userstate),
-                prRoot = Just $
-                    reattachHereDocs script (hereDocMap userstate)
+                prRoot = Just script
            }
        Left err -> do
            let context = contextStack state
@ -3490,13 +3533,11 @@ parseShell env name contents = do
    -- A final pass for ignoring parse errors after failed parsing
    isIgnored stack note = any (contextItemDisablesCode False (codeForParseNote note)) stack

-notesForContext list = zipWith ($) [first, second] $ filter isName list
+notesForContext list = zipWith ($) [first, second] [(pos, str) | ContextName pos str <- list]
  where
-    isName (ContextName _ _) = True
-    isName _ = False
-    first (ContextName pos str) = ParseNote pos pos ErrorC 1073 $
+    first (pos, str) = ParseNote pos pos ErrorC 1073 $
        "Couldn't parse this " ++ str ++ ". Fix to allow more checks."
-    second (ContextName pos str) = ParseNote pos pos InfoC 1009 $
+    second (pos, str) = ParseNote pos pos InfoC 1009 $
        "The mentioned syntax error was in this " ++ str ++ "."

 -- Go over all T_UnparsedIndex and reparse them as either arithmetic or text
--- a/test/check_release
+++ b/test/check_release
@ -12,6 +12,17 @@ then
  fail "There are uncommitted changes"
 fi

+version=${current#v}
+if ! grep "Version:" ShellCheck.cabal | grep -qFw "$version"
+then
+  fail "The cabal file does not match tag version $version"
+fi
+
+if ! grep -qF "## $current" CHANGELOG.md
+then
+  fail "CHANGELOG.md does not contain '## $current'"
+fi
+
 current=$(git tag --points-at)
 if [[ -z "$current" ]]
 then
@ -34,33 +45,30 @@ then
  fail "You are not on master"
 fi

-version=${current#v}
-if ! grep "Version:" ShellCheck.cabal | grep -qFw "$version"
-then
-  fail "The cabal file does not match tag version $version"
-fi
-
-if ! grep -qF "## $current" CHANGELOG.md
-then
-  fail "CHANGELOG.md does not contain '## $current'"
-fi
-
 if [[ $(git log -1 --pretty=%B) != "Stable version "* ]]
 then
  fail "Expected git log message to be 'Stable version ...'"
 fi

+if [[ $(git log -1 --pretty=%B) != *"CHANGELOG"* ]]
+then
+  fail "Expected git log message to contain CHANGELOG"
+fi
+
 i=1 j=1
 cat << EOF

 Manual Checklist

 $((i++)). Make sure none of the automated checks above failed
+$((i++)). Run \`build/build_builder build/*/\` to update all builder images.
+$((j++)). \`build/run_builder dist-newstyle/sdist/ShellCheck-*.tar.gz build/*/\` to verify that they work.
+$((j++)). \`for f in \$(cat build/*/tag); do docker push "\$f"; done\` to upload them.
+$((i++)). Run test/distrotest to ensure that most distros can build OOTB.
 $((i++)). Make sure GitHub Build currently passes: https://github.com/koalaman/shellcheck/actions
 $((i++)). Make sure SnapCraft build currently works: https://build.snapcraft.io/user/koalaman
-$((i++)). Run test/distrotest to ensure that most distros can build OOTB.
 $((i++)). Format and read over the manual for bad formatting and outdated info.
-$((i++)). Make sure the Hackage package builds.
+$((i++)). Make sure the Hackage package builds locally.

 Release Steps

--- a/test/distrotest
+++ b/test/distrotest
@ -17,13 +17,13 @@ and is still highly experimental.
 Make sure you're plugged in and have screen/tmux in place,
 then re-run with $0 --run to continue.

-Also note that dist* will be deleted.
+Also note that dist*/ and .stack-work/ will be deleted.
 EOF
 exit 0
 }

-echo "Deleting 'dist' and 'dist-newstyle'..."
-rm -rf dist dist-newstyle
+echo "Deleting 'dist', 'dist-newstyle', and '.stack-work'..."
+rm -rf dist dist-newstyle .stack-work

 execs=$(find . -name shellcheck)

@ -74,13 +74,12 @@ fedora:latest         dnf install -y cabal-install ghc-template-haskell-devel fi
 archlinux:latest      pacman -S -y --noconfirm cabal-install ghc-static base-devel

 # Ubuntu LTS
+ubuntu:24.04          apt-get update && apt-get install -y cabal-install
 ubuntu:22.04          apt-get update && apt-get install -y cabal-install
 ubuntu:20.04          apt-get update && apt-get install -y cabal-install
-ubuntu:18.04          apt-get update && apt-get install -y cabal-install
-ubuntu:16.04          apt-get update && apt-get install -y cabal-install

 # Stack on Ubuntu LTS
-ubuntu:22.04          set -e; apt-get update && apt-get install -y curl && curl -sSL https://get.haskellstack.org/ | sh -s - -f && cd /mnt && exec test/stacktest
+ubuntu:24.04          set -e; apt-get update && apt-get install -y curl && curl -sSL https://get.haskellstack.org/ | sh -s - -f && cd /mnt && exec test/stacktest
 EOF

 exit "$final"
--- a/test/shellcheck.hs
+++ b/test/shellcheck.hs
@ -18,21 +18,24 @@ import qualified ShellCheck.Parser

 main = do
    putStrLn "Running ShellCheck tests..."
-    results <- sequence [
-        ShellCheck.Analytics.runTests
-        ,ShellCheck.AnalyzerLib.runTests
-        ,ShellCheck.ASTLib.runTests
-        ,ShellCheck.CFG.runTests
-        ,ShellCheck.CFGAnalysis.runTests
-        ,ShellCheck.Checker.runTests
-        ,ShellCheck.Checks.Commands.runTests
-        ,ShellCheck.Checks.ControlFlow.runTests
-        ,ShellCheck.Checks.Custom.runTests
-        ,ShellCheck.Checks.ShellSupport.runTests
-        ,ShellCheck.Fixer.runTests
-        ,ShellCheck.Formatter.Diff.runTests
-        ,ShellCheck.Parser.runTests
+    failures <- filter (not . snd) <$> mapM sequenceA tests
+    if null failures then exitSuccess else do
+      putStrLn "Tests failed for the following module(s):"
+      mapM (putStrLn . ("- ShellCheck." ++) . fst) failures
+      exitFailure
+  where
+    tests =
+      [ ("Analytics"          , ShellCheck.Analytics.runTests)
+      , ("AnalyzerLib"        , ShellCheck.AnalyzerLib.runTests)
+      , ("ASTLib"             , ShellCheck.ASTLib.runTests)
+      , ("CFG"                , ShellCheck.CFG.runTests)
+      , ("CFGAnalysis"        , ShellCheck.CFGAnalysis.runTests)
+      , ("Checker"            , ShellCheck.Checker.runTests)
+      , ("Checks.Commands"    , ShellCheck.Checks.Commands.runTests)
+      , ("Checks.ControlFlow" , ShellCheck.Checks.ControlFlow.runTests)
+      , ("Checks.Custom"      , ShellCheck.Checks.Custom.runTests)
+      , ("Checks.ShellSupport", ShellCheck.Checks.ShellSupport.runTests)
+      , ("Fixer"              , ShellCheck.Fixer.runTests)
+      , ("Formatter.Diff"     , ShellCheck.Formatter.Diff.runTests)
+      , ("Parser"             , ShellCheck.Parser.runTests)
      ]
-    if and results
-      then exitSuccess
-      else exitFailure
--- a/test/stacktest
+++ b/test/stacktest
@ -15,7 +15,7 @@ die() { echo "$*" >&2; exit 1; }
 command -v stack ||
  die "stack is missing"

-stack setup        || die "Failed to setup with default resolver"
+stack setup --allow-different-user || die "Failed to setup with default resolver"
 stack build --test || die "Failed to build/test with default resolver"

 # Nice to haves, but not necessary