Repository: dotnet/efcore
File: src/EFCore/Query/Internal/ExpressionTreeFuncletizer.cs (C#)

Code before:
    {
        var evaluateAsParameter = true;
        return Evaluate(expression, ref evaluateAsParameter, out parameterName, out _);
    }

    private object? Evaluate(Expression? expression, ref bool evaluateAsParameter, out string parameterName, out bool isContextAccessor)
    {
        var value = EvaluateCore(expression, ref evaluateAsParameter, out var tempParameterName, out isContextAccessor);

        if (evaluateAsParameter)
        {
            parameterName = tempParameterName ?? "p";

            // The VB compiler prefixes closure member names with $VB$Local_, remove that (#33150)
            if (parameterName.StartsWith("$VB$Local_", StringComparison.Ordinal))
            {
                parameterName = parameterName.Substring("$VB$Local_".Length);
            }

            // In many databases, parameter names must start with a letter or underscore.
            // The same is true for C# variable names, from which we derive the parameter name, so in principle we shouldn't see an issue;
            // but just in case, prepend an underscore if the parameter name doesn't start with a letter or underscore.
            if (!char.IsLetter(parameterName[0]) && parameterName[0] != '_')
            {
                parameterName = "_" + parameterName;
            }

            parameterName = Uniquifier.Uniquify(parameterName, _parameterNames, maxLength: int.MaxValue, uniquifier: _parameterNames.Count);

            _parameterNames.Add(parameterName);
        }
        else
        {
            parameterName = string.Empty;
        }

        return value;

        object? EvaluateCore(Expression? expression, ref bool evaluateAsParameter, out string? parameterName, out bool isContextAccessor)
        {
            parameterName = null;
            isContextAccessor = false;

            if (expression == null)
            {
                return null;
            }

            if (_generateContextAccessors)
            {
                var visited = _contextParameterReplacer.Visit(expression);

Review comment (bug):
There's a potential IndexOutOfRangeException if parameterName is an empty string. The SanitizeCompilerGeneratedName method could return an empty string in edge cases (e.g., when the input is ">"), and the null coalescing operator at line 2083 doesn't catch empty strings. Consider checking for empty strings before accessing parameterName[0], or ensure SanitizeCompilerGeneratedName never returns an empty string.

Code after:
    {
        var evaluateAsParameter = true;
        return Evaluate(expression, ref evaluateAsParameter, out parameterName, out _);
    }

    private object? Evaluate(Expression? expression, ref bool evaluateAsParameter, out string parameterName, out bool isContextAccessor)
    {
        var value = EvaluateCore(expression, ref evaluateAsParameter, out var tempParameterName, out isContextAccessor);

        if (evaluateAsParameter)
        {
            parameterName = string.IsNullOrWhiteSpace(tempParameterName) ? "p" : tempParameterName;

            // The VB compiler prefixes closure member names with $VB$Local_, remove that (#33150)
            if (parameterName.StartsWith("$VB$Local_", StringComparison.Ordinal))
            {
                parameterName = parameterName.Substring("$VB$Local_".Length);
            }

            // In many databases, parameter names must start with a letter or underscore.
            // The same is true for C# variable names, from which we derive the parameter name, so in principle we shouldn't see an issue;
            // but just in case, prepend an underscore if the parameter name doesn't start with a letter or underscore.
            if (!char.IsLetter(parameterName[0]) && parameterName[0] != '_')
            {
                parameterName = "_" + parameterName;
            }

            parameterName = Uniquifier.Uniquify(parameterName, _parameterNames, maxLength: int.MaxValue, uniquifier: _parameterNames.Count);

            _parameterNames.Add(parameterName);
        }
        else
        {
            parameterName = string.Empty;
        }

        return value;

        object? EvaluateCore(Expression? expression, ref bool evaluateAsParameter, out string? parameterName, out bool isContextAccessor)
        {
            parameterName = null;
            isContextAccessor = false;

            if (expression == null)
            {
                return null;
            }

            if (_generateContextAccessors)
            {
                var visited = _contextParameterReplacer.Visit(expression);