HelperFunctions.cs

using Microsoft.Dynamics.Nav.CodeAnalysis;

namespace BusinessCentral.LinterCop.Helpers {
    public class HelperFunctions {
        public static bool MethodImplementsInterfaceMethod(IMethodSymbol methodSymbol)
        {
            return MethodImplementsInterfaceMethod(methodSymbol.GetContainingApplicationObjectTypeSymbol(), methodSymbol);
        }

        public static bool MethodImplementsInterfaceMethod(IApplicationObjectTypeSymbol objectSymbol, IMethodSymbol methodSymbol)
        {
            if (!(objectSymbol is ICodeunitTypeSymbol))
            {
                return false;
            }

            var codeunitSymbol = objectSymbol as ICodeunitTypeSymbol;
            foreach (var implementedInterface in codeunitSymbol.ImplementedInterfaces)
            {
                if (implementedInterface.GetMembers().OfType<IMethodSymbol>().Any(interfaceMethodSymbol => MethodImplementsInterfaceMethod(methodSymbol, interfaceMethodSymbol)))
                {
                    return true;
                }
            }

            return false;
        }

        public static bool MethodImplementsInterfaceMethod(IMethodSymbol methodSymbol, IMethodSymbol interfaceMethodSymbol)
        {
            if (methodSymbol.Name != interfaceMethodSymbol.Name)
            {
                return false;
            }
            if (methodSymbol.Parameters.Length != interfaceMethodSymbol.Parameters.Length)
            {
                return false;
            }
            var methodReturnValType = methodSymbol.ReturnValueSymbol?.ReturnType.NavTypeKind ?? NavTypeKind.None;
            var interfaceMethodReturnValType = interfaceMethodSymbol.ReturnValueSymbol?.ReturnType.NavTypeKind ?? NavTypeKind.None;
            if (methodReturnValType != interfaceMethodReturnValType)
            {
                return false;
            }
            for (int i = 0; i < methodSymbol.Parameters.Length; i++)
            {
                var methodParameter = methodSymbol.Parameters[i];
                var interfaceMethodParameter = interfaceMethodSymbol.Parameters[i];

                if (methodParameter.IsVar != interfaceMethodParameter.IsVar)
                {
                    return false;
                }
                if (!methodParameter.ParameterType.Equals(interfaceMethodParameter.ParameterType))
                {
                    return false;
                }
            }
            return true;
        }
    }
}