diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 26cdb82d8f..76e66a2a09 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -210,3 +210,102 @@ jobs:
             After="${{github.event.after}}"
         fi
         bash _scripts/test.sh -a /tmp/antlr4-complete.jar -t ${{matrix.language}} -f diff $Before $After
+
+  static-checks:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ ubuntu-latest]
+        language: [ CSharp ]
+    steps:
+    - name: Info
+      shell: bash
+      run: |
+        arch
+        uname -a
+        if [ -f /proc/cpuinfo ]; then cat /proc/cpuinfo; fi
+    - name: Checkout
+      uses: actions/checkout@v3
+      with:
+        fetch-depth: 0
+    - name: Install Dotnet
+      uses: actions/setup-dotnet@v3.2.0
+      with:
+        dotnet-version: '7.0.x'
+    - name: Test Dotnet
+      run: |
+        dotnet --version
+        dotnet --info
+        dotnet --list-runtimes
+        dotnet --list-sdks
+    - name: Install Java
+      uses: actions/setup-java@v3
+      with:
+        java-version: '11'
+        distribution: 'zulu'
+    - name: Test Java
+      run: |
+        dotnet --version
+        java --version
+        javac --version
+    - name: Install Dart
+      if: ${{ matrix.language == 'Dart' }}
+      uses: dart-lang/setup-dart@v1
+    - name: Test Dart
+      if: ${{ matrix.language == 'Dart' }}
+      run: |
+        dart --version
+    - name: Install Go
+      if: ${{ matrix.language == 'Go' }}
+      uses: actions/setup-go@v4
+      with:
+        go-version: '^1.18.0'
+    - name: Test Go
+      if: ${{ matrix.language == 'Go' }}
+      run: |
+        go version
+    - name: Install Python
+      uses: actions/setup-python@v4.6.1
+      with:
+        python-version: '3.10'
+    - name: Test Python
+      run: |
+        python --version
+    - name: Upgrade Pip.
+      run: |
+        python -m ensurepip --upgrade
+    - name: Test Pip.
+      run: |
+        pip --version
+    - name: Install Antlr tool
+      run: |
+         pip install antlr4-tools
+    - name: Install JavaScript
+      if: ${{ matrix.language == 'JavaScript' }}
+      uses: actions/setup-node@v3.6.0
+      with:
+        node-version: '16.13.0'
+    - name: Test JavaScript
+      if: ${{ matrix.language == 'JavaScript' }}
+      run: |
+        node --version
+    - name: Install Trash
+      shell: bash
+      run: |
+        dotnet tool restore
+    - name: Test Trash install
+      shell: bash
+      run: |
+        dotnet trgen -- --help
+    - name: Test
+      shell: bash
+      run: |
+        if [ "${{github.event_name}}" == "pull_request" ]; then
+            Before="${{github.event.pull_request.base.sha}}"
+            After="${{github.event.pull_request.head.sha}}"
+        else
+            Before="${{github.event.before}}"
+            After="${{github.event.after}}"
+        fi
+        bash _scripts/test-static-checks.sh -t ${{matrix.language}} -f diff $Before $After
diff --git a/_scripts/test-static-checks.sh b/_scripts/test-static-checks.sh
new file mode 100644
index 0000000000..6e2d1d7acb
--- /dev/null
+++ b/_scripts/test-static-checks.sh
@@ -0,0 +1,358 @@
+#!/usr/bin/bash
+
+myrealpath ()                                                                                                                                                                                   
+{                                                                                                                                                                                             
+    f=$@;                                                                                                                                                                                     
+    if [ -d "$f" ]; then                                                                                                                                                                      
+        base="";                                                                                                                                                                              
+        dir="$f";                                                                                                                                                                             
+    else                                                                                                                                                                                      
+        base="/$(basename "$f")";                                                                                                                                                             
+        dir=$(dirname "$f");                                                                                                                                                                  
+    fi;                                                                                                                                                                                       
+    dir=$(cd "$dir" && /bin/pwd);                                                                                                                                                             
+    echo "$dir$base"                                                                                                                                                                          
+}
+
+# true or false
+quiet=true
+
+# Get full path of this script.
+full_path_script=$(myrealpath $0)
+full_path_templates=$(dirname $full_path_script)/templates
+
+# Sanity checks for required environment.
+unameOut="$(uname -s)"
+case "${unameOut}" in
+    Linux*)     machine=Linux;;
+    Darwin*)    machine=Mac;;
+    CYGWIN*)    machine=Cygwin;;
+    MINGW*)     machine=MinGw;;
+    *)          machine="UNKNOWN:${unameOut}"
+esac
+if [[ "$machine" != "Linux" && "$machine" != "Mac" && "$machine" != "MinGw" ]]
+then
+    echo "This script runs only in a Linux environment. Skipping."
+    exit 0
+fi
+
+thetime()
+{
+    local hh
+    local DIFF
+    DIFF=$1
+    hh="$(($DIFF / 3600 ))"
+    mm="$((($DIFF % 3600) / 60))"
+    ss="$(($DIFF % 60))"
+    printf "%02d:%02d:%02d" $hh $mm $ss
+}
+
+function getopts-extra () {
+    OPTARG=()
+    declare i=0
+    # if the next argument is not an option, then append it to array OPTARG
+    while [[ ${OPTIND} -le $# && ${!OPTIND:0:1} != '-' ]]; do
+        OPTARG[i]=${!OPTIND}
+        let i++ OPTIND++
+    done
+}
+
+# filter="all" or "diff" or "agnostic"
+filter="all"
+# order="grammar" or "target"
+order="grammar"
+failed=()
+succeeded=()
+skipped=""
+grammars=()
+targets=()
+tests=()
+
+# Get "root" of the repo clone.
+cwd=`pwd`
+prefix=`pwd`
+pushd $prefix > /dev/null 2>&1
+while true
+do
+    if [ -f `pwd`/_scripts/test.sh ]
+    then
+        break
+    elif [ `pwd` == "/" ]
+    then
+        break
+    fi
+    cd ..
+done
+if [ ! -f `pwd`/_scripts/test.sh ]
+then
+    echo "Not in repo."
+    exit 1
+fi
+prefix=`pwd`
+popd > /dev/null 2>&1
+
+rm -rf `find . -name 'Generated*' -type d`
+
+# Parse args, and update computation to perform.
+order="grammars"
+additional=()
+antlr4jar=/tmp/antlr4-complete.jar
+while getopts 'agthf' opt; do
+    case "$opt" in
+        a)
+            getopts-extra "$@"
+            antlr4jar="${OPTARG[0]}"
+        echo Antlr4jar is $antlr4jar
+            ;;
+        g)
+            getopts-extra "$@"
+            for a in "${OPTARG[@]}"
+            do
+                grammars+=( "$a" )
+            done
+            ;;
+        t)
+            getopts-extra "$@"
+            for a in "${OPTARG[@]}"
+            do
+                targets+=( "$a" )
+            done
+            ;;
+        o)
+            order="$OPTARG"
+            ;;
+        f)
+            getopts-extra "$@"
+            filter="${OPTARG[0]}"
+            for a in "${OPTARG[@]:1}"
+            do
+                additional+=( "$a" )
+            done
+            ;;
+        ?|h)
+            cat - <<EOF
+NAME
+       test - tests Antlr4 grammars
+
+SYNOPSIS
+       $(basename $0) ([-g ...] | [-s ...] | [-t ...])
+
+DESCRIPTION
+       Tests Antlr4 grammars. Each grammar requires pom.xml and desc.xml files.
+
+OPTIONS
+       -g
+           Specifies a list of directories that are searched for grammars.
+           A grammar requires pom.xml and desc.xml files for it to be tested.
+           If the option is not specified, then the default is to search from
+           the current directory. Searching is subject to filters.
+
+       -f
+           Specifies the type of testing to filter. Possible types are "diff",
+           "all", or "agnostic". The default is "all".
+
+       -t
+           Specifies the targets to test. Possible targets are
+           "CSharp", "Cpp", "Dart", "Go", "Java", "JavaScript", "PHP", "Python3".
+           All targets are tested by default.
+
+EOF
+            exit 0
+            ;;
+    esac
+done
+
+if [ "$filter" == "diff" ]
+then
+    if [ "${#additional[@]}" -eq 0 ]
+    then
+        diffs=`git diff --exit-code --name-only .`
+        if [ "$diffs" != "" ]
+        then
+            grammars=()
+            # Test grammars for the enclosing directories.
+            directories=`git diff --name-only . 2> /dev/null | sed 's#\(.*\)[/][^/]*$#\1#' | sort -u | grep -v _scripts`
+            for g in $directories
+            do
+                pushd $g > /dev/null
+                while true
+                do
+                    if [ -f `pwd`/desc.xml ]
+                    then
+                        break
+                    elif [ `pwd` == "$prefix" ]
+                    then
+                        break
+                    fi
+                    cd ..
+                done
+                g=`pwd`
+                g=${g##*$prefix}
+                g=${g##/}
+                if [ "$g" == "" ]
+                then
+                    g="."
+                fi
+                popd > /dev/null
+                echo Adding diff $g
+                grammars+=( $g )
+            done
+            grammars=( $(for g in "${grammars[@]}"; do echo "${g}"; done | sort -u) )
+        fi
+    elif [ "${#additional[@]}" -eq 2 ]
+    then
+        grammars=()
+        # Test grammars for the enclosing directories.
+        directories=`git diff --name-only ${additional[0]} ${additional[1]} . 2> /dev/null | sed 's#\(.*\)[/][^/]*$#\1#' | sort -u | grep -v _scripts`
+        for g in $directories
+        do
+            pushd $g > /dev/null
+            while true
+            do
+                if [ -f `pwd`/desc.xml ]
+                then
+                    break
+                elif [ `pwd` == "$prefix" ]
+                then
+                    break
+                fi
+                cd ..
+            done
+            g=`pwd`
+            g=${g##*$prefix}
+            g=${g##/}
+            if [ "$g" == "" ]
+            then
+                g="."
+            fi
+            popd > /dev/null
+            echo Adding diff $g
+            grammars+=( $g )
+        done
+    else
+        echo ouch
+        exit 1
+    fi
+elif [ "$filter" == "all" ]
+then
+    grammars=()
+    # Test grammars for the enclosing directories.
+    directories=`find . -name desc.xml | sed 's#/desc.xml##' | sort -u`
+    for g in $directories
+    do
+        pushd $g > /dev/null 2>&1
+        g=`pwd`
+        g=${g##*$prefix/}
+        popd > /dev/null 2>&1
+        echo Adding $g
+        grammars+=( $g )
+    done
+    grammars=( $(for g in "${grammars[@]}"; do echo "${g}"; done | sort -u) )
+elif [ "$filter" != "all" ]
+then
+    echo Unknown filter $filter
+    exit 1
+fi
+
+echo "Number of grammars before sorting and making unique: ${#grammars[@]}"
+grammars=($(echo "${grammars[@]}" | tr ' ' '\n' | sort -u | tr '\n' ' '))
+echo "Number of grammars after sorting and making unique: ${#grammars[@]}"
+
+if [ "${#grammars[@]}" -eq 0 ]
+then
+    echo There are no grammars in current directory to test.
+    exit 0
+else
+    echo Grammars to do are: ${grammars[@]}
+fi
+
+if [ "$targets" == "" ]
+then
+    targets=( CSharp Cpp Dart Go Java JavaScript PHP Python3 TypeScript )
+fi
+
+echo grammars = ${grammars[@]}
+echo targets = ${targets[@]}
+echo order = $order
+echo filter = $filter
+
+# Compute cross product
+for g in ${grammars[@]}
+do
+    for t in ${targets[@]}
+    do
+        tests+=( "$g,$t" )
+    done
+done
+
+# Sort the list of <grammar, target> tuples if needed.
+if [[ "$order" == "grammars" ]]; then sorted="1"; else sorted="2"; fi
+#tests=`echo $tests | fmt -w 1 | sort -t ',' -k "$sorted"`
+
+echo Tests now ${tests[@]}
+
+# Perform tests in order.
+for test in ${tests[@]}
+do
+    all=( $(echo $test | tr "," "\n") )
+    testname=${all[0]}
+    target=${all[1]}
+    pushd "$prefix/$testname" > /dev/null
+
+    echo ""
+    echo "$testname,$target:"
+
+    if [ ! -f desc.xml ]
+    then
+        echo No desc.xml for $testname
+        popd > /dev/null
+        continue
+    fi
+    desc_targets=`dotnet trxml2 -- desc.xml | grep '/desc/targets'`
+    if [ "${PIPESTATUS[0]}" -ne 0 ]
+    then
+        echo "The desc.xml for $testname is malformed. Skipping."
+        popd > /dev/null
+        continue
+    fi
+    desc_targets="${desc_targets##*=}"
+    desc_targets=`echo "$desc_targets" | tr ',' ' ' | tr ';' ' '`
+
+    yes=false;
+    for t in $desc_targets
+    do
+        if [ "$t" == "+all" ]; then yes=true; fi
+        if [ "$t" == "-$target" ]; then yes=false; fi
+        if [ "$t" == "$target" ]; then yes=true; fi
+    done
+
+    if [ "$yes" == "false" ]
+    then
+        echo "Intentionally skipping grammar $testname target $target."
+        popd > /dev/null
+        continue
+    fi
+
+    if [ "$filter" == "agnostic" ]
+    then
+        # Test whether the grammars have actions.
+        count=`dotnet trparse -- -t antlr4 *.g4 2> /dev/null | dotnet trxgrep ' //(actionBlock | argActionBlock)' | dotnet trtext -c`
+        if [ "$count" == "0" ]
+        then
+            echo "no actions => skipping $testname."
+            popd > /dev/null
+            continue
+        fi
+    fi
+
+    curl https://raw.githubusercontent.com/kaby76/g4-checks/d0e97c52787c9f47d6c3dd94f26159531fee7ee0/find-useless.sh 2> /dev/null | bash 1>&2
+
+    popd > /dev/null
+done
+
+if [[ "$failed" == "" ]]
+then
+    exit 0
+else
+    exit 1
+fi
diff --git a/_scripts/test.sh b/_scripts/test.sh
index 9f001998c3..23e1abdd0a 100644
--- a/_scripts/test.sh
+++ b/_scripts/test.sh
@@ -353,7 +353,7 @@ do
 
     for d in `echo Generated-$target-* Generated-$target`
     do
-	if [ ! -d $d ]; then continue; fi
+        if [ ! -d $d ]; then continue; fi
         if [ ! -f $d/build.sh ]; then echo " no build.sh"; continue; fi
 
         # Build driver code.
@@ -400,6 +400,7 @@ do
             echo " Succeeded."      
             succeeded+=( "$testname,$target" )
         fi
+
         popd > /dev/null
     done
     popd > /dev/null
diff --git a/abb/abbParser.g4 b/abb/abbParser.g4
index fa7031f25e..730781d869 100644
--- a/abb/abbParser.g4
+++ b/abb/abbParser.g4
@@ -103,4 +103,4 @@ primitive
     | STRINGLITERAL
     | (PLUS | MINUS)? FLOATLITERAL
     | (PLUS | MINUS)? INTLITERAL
-    ;
\ No newline at end of file
+    ;
diff --git a/abb/examples/robdata.sys.errors b/abb/examples/robdata.sys.errors
new file mode 100644
index 0000000000..e69de29bb2