diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..35ab0d3
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,6 @@
+# Third party
+/composer.lock
+/phpunit.xml
+/vendor
+/.couscous
+/.puli
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..c955756
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,32 @@
+language: php
+
+sudo: false
+
+cache:
+    directories:
+        - $HOME/.composer/cache
+
+php:
+  - 5.3
+  - 5.4
+  - 5.5
+  - 5.6
+  - 7.0
+  - hhvm
+
+matrix:
+#    include:
+#        - php: 5.3.3
+#          env: COMPOSER_FLAGS="--prefer-lowest"
+  allow_failures:
+    - php: hhvm
+    - php: 7.0
+
+before_script:
+  - curl http://cs.sensiolabs.org/get/php-cs-fixer.phar -o php-cs-fixer.phar
+  - composer selfupdate
+  - composer update $COMPOSER_FLAGS
+
+script:
+  - echo '[phpspec] Running specification tests'; ./vendor/bin/phpspec run -n -f dot
+  - output=$(php -n php-cs-fixer.phar fix -v --dry-run --config=sf23 .); if [[ $(grep -o F <<< $output | wc -l) -gt 3 ]]; then while read -r line; do echo -e "\e[00;31m$line\e[00m"; done <<< "$output"; false; fi;
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..cc04eca
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,5 @@
+# CHANGELOG
+
+## 1.0.0: Import
+
+* imported constraints from [memio/validator](http://github.com/memio/validator) v1.0.0-rc1
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..12a85c3
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,63 @@
+# How to contribute
+
+Everybody should be able to help. Here's how you can make this project more
+awesome:
+
+1. [Fork it](https://github.com/memio/linter/fork_select)
+2. improve it
+3. submit a [pull request](https://help.github.com/articles/creating-a-pull-request)
+
+Your work will then be reviewed as soon as possible (suggestions about some
+changes, improvements or alternatives may be given).
+
+Here's some tips to make you the best contributor ever:
+
+* [Standard code](#standard-code)
+* [Specifications](#specifications)
+* [Keeping your fork up-to-date](#keeping-your-fork-up-to-date)
+
+## Standard code
+
+Use [PHP CS fixer](http://cs.sensiolabs.org/) to make your code compliant with
+Memio Linter's coding standards:
+
+    ./vendor/bin/php-cs-fixer fix --config=sf23 .
+
+## Specifications
+
+Memio Linter drives its development using [phpspec](http://www.phpspec.net/):
+
+    # Generate the specification class:
+    phpspec describe 'Memio\Validator\MyNewClass'
+
+    # Customize the specification class:
+    $EDITOR spec/Memio/Linter/MyNewClass.php
+
+    # Generate the specified class:
+    phpspec run
+
+    # Customize the class:
+    $EDITOR src/Memio/Linter/MyNewClass.php
+
+    phpspec run # Should be green!
+
+## Keeping your fork up-to-date
+
+To keep your fork up-to-date, you should track the upstream (original) one
+using the following command:
+
+    git remote add upstream https://github.com/memio/linter.git
+
+Then get the upstream changes:
+
+    git checkout master
+    git pull --rebase origin master
+    git pull --rebase upstream master
+    git checkout <your-branch>
+    git rebase master
+
+Finally, publish your changes:
+
+    git push -f origin <your-branch>
+
+Your pull request will be automatically updated.
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..ba0bc4d
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2015 Loïc Chardonnet
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..8fc85be
--- /dev/null
+++ b/README.md
@@ -0,0 +1,102 @@
+# Memio's Linter [![Travis CI](https://travis-ci.org/memio/linter.png)](https://travis-ci.org/memio/linter) [![SensioLabsInsight](https://insight.sensiolabs.com/projects/e5794d5b-5305-4569-bc9b-caeecf9ae982/mini.png)](https://insight.sensiolabs.com/projects/e5794d5b-5305-4569-bc9b-caeecf9ae982)
+
+A set of [Memio constraints](http://github.com/memio/validator) that check
+[Memio models](http://github.com/memio/model) for syntax errors and the likes.
+
+> **Note**: This package is part of [Memio](http://memio.github.io/memio), a highly opinionated PHP code generator.
+> Have a look at [the main repository](http://github.com/memio/memio).
+
+## Installation
+
+Install it using [Composer](https://getcomposer.org/download):
+
+    composer require memio/linter:~1.0
+
+## Example
+
+Usually we'd have to install [Memio](http://github.com/memio/memio) and use its
+`Build::linter()` method to get a linter validator.
+
+The atlernative would be to build manually the validator as follow:
+
+```php
+<?php
+
+require __DIR__.'/vendor/autoload.php';
+
+use Memio\Validator\Constraint\ArgumentCannotBeScalar;
+use Memio\Validator\Constraint\CollectionCannotHaveNameDuplicates;
+use Memio\Validator\Constraint\ConcreteObjectMethodsCannotBeAbstract;
+use Memio\Validator\Constraint\ContractMethodsCanOnlyBePublic;
+use Memio\Validator\Constraint\ContractMethodsCannotBeFinal;
+use Memio\Validator\Constraint\ContractMethodsCannotBeStatic;
+use Memio\Validator\Constraint\ContractMethodsCannotHaveBody;
+use Memio\Validator\Constraint\MethodCannotBeAbstractAndHaveBody;
+use Memio\Validator\Constraint\MethodCannotBeBothAbstractAndFinal;
+use Memio\Validator\Constraint\MethodCannotBeBothAbstractAndPrivate;
+use Memio\Validator\Constraint\MethodCannotBeBothAbstractAndStatic;
+use Memio\Validator\Constraint\ObjectArgumentCanOnlyDefaultToNull;
+use Memio\Validator\ModelValidator\ArgumentValidator;
+use Memio\Validator\ModelValidator\CollectionValidator;
+use Memio\Validator\ModelValidator\MethodValidator;
+use Memio\Validator\ModelValidator\ContractValidator;
+use Memio\Validator\ModelValidator\ObjectValidator;
+use Memio\Validator\ModelValidator\FileValidator;
+use Memio\Validator\Validator;
+
+$argumentValidator = new ArgumentValidator();
+$argumentValidator->add(new ArgumentCannotBeScalar());
+
+$collectionValidator = new CollectionValidator();
+$collectionValidator->add(new CollectionCannotHaveNameDuplicates());
+
+$methodValidator = new MethodValidator($argumentValidator, $collectionValidator);
+$methodValidator->add(new MethodCannotBeAbstractAndHaveBody());
+$methodValidator->add(new MethodCannotBeBothAbstractAndFinal());
+$methodValidator->add(new MethodCannotBeBothAbstractAndPrivate());
+$methodValidator->add(new MethodCannotBeBothAbstractAndStatic());
+
+$contractValidator = new ContractValidator($collectionValidator, $methodValidator);
+$contractValidator->add(new ContractMethodsCanOnlyBePublic());
+$contractValidator->add(new ContractMethodsCannotBeFinal());
+$contractValidator->add(new ContractMethodsCannotBeStatic());
+$contractValidator->add(new ContractMethodsCannotHaveBody());
+
+$objectValidator = new ObjectValidator($collectionValidator, $methodValidator);
+$objectValidator->add(new ConcreteObjectMethodsCannotBeAbstract());
+$objectValidator->add(new ObjectArgumentCanOnlyDefaultToNull());
+
+$fileValidator = new FileValidator($contractValidator, $objectValidator);
+
+$linter = new Validator();
+$linter->add($argumentValidator);
+$linter->add($collectionValidator);
+$linter->add($methodValidator);
+$linter->add($contractValidator);
+$linter->add($objectValidator);
+$linter->add($fileValidator);
+
+$linter->validator($anyModels);
+```
+
+Have a look at [the main respository](http://github.com/memio/memio) to discover the full power of Medio.
+
+## Want to know more?
+
+Memio uses [phpspec](http://phpspec.net/), which means the tests also provide the documentation.
+Not convinced? Then clone this repository and run the following commands:
+
+    composer install
+    ./vendor/bin/phpspec run -n -f pretty
+
+You can see the current and past versions using one of the following:
+
+* the `git tag` command
+* the [releases page on Github](https://github.com/memio/memio/releases)
+* the file listing the [changes between versions](CHANGELOG.md)
+
+And finally some meta documentation:
+
+* [copyright and MIT license](LICENSE)
+* [versioning and branching models](VERSIONING.md)
+* [contribution instructions](CONTRIBUTING.md)
diff --git a/VERSIONING.md b/VERSIONING.md
new file mode 100644
index 0000000..9e005bd
--- /dev/null
+++ b/VERSIONING.md
@@ -0,0 +1,27 @@
+# Versioning and branching models
+
+This file explains the versioning and branching models of this project.
+
+## Versioning
+
+The versioning is inspired by [Semantic Versioning](http://semver.org/):
+
+> Given a version number MAJOR.MINOR.PATCH, increment the:
+>
+> 1. MAJOR version when you make incompatible API changes
+> 2. MINOR version when you add functionality in a backwards-compatible manner
+> 3. PATCH version when you make backwards-compatible bug fixes
+
+### Public API
+
+Classes and methods marked with the `@api` tag are considered to be the public
+API of this project.
+
+## Branching Model
+
+The branching is inspired by [@jbenet](https://github.com/jbenet)
+[simple git branching model](https://gist.github.com/jbenet/ee6c9ac48068889b0912):
+
+> 1. `master` must always be deployable.
+> 2. **all changes** are made through feature branches (pull-request + merge)
+> 3. rebase to avoid/resolve conflicts; merge in to `master`
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..3d111a3
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,29 @@
+{
+    "name": "memio/linter",
+    "license": "MIT",
+    "type": "library",
+    "description": "Memio's linter, a set of constraint that check models for syntax errors",
+    "keywords": ["generator", "PHP", "code"],
+    "homepage": "http://memio.github.io/memio",
+    "authors": [
+        {
+            "name": "Loïc Chardonnet",
+            "email": "loic.chardonnet@gmail.com",
+            "homepage": "http://gnugat.github.io",
+            "role": "Developer"
+        }
+    ],
+    "autoload": { "psr-4": {
+        "Memio\\Linter\\": "src/Memio/Linter"
+    }},
+    "require": {
+        "php": ">=5.3.3",
+        "memio/model": "~1.0",
+        "memio/validator": "~1.0"
+    },
+    "require-dev": {
+        "ciaranmcnulty/phpspec-typehintedmethods": "~1.1",
+        "fabpot/php-cs-fixer": "~1.6",
+        "phpspec/phpspec": "~2.2"
+    }
+}
diff --git a/phpspec.yml b/phpspec.yml
new file mode 100644
index 0000000..c1c2a05
--- /dev/null
+++ b/phpspec.yml
@@ -0,0 +1,2 @@
+extensions:
+    - Cjm\PhpSpec\Extension\TypeHintedMethodsExtension
diff --git a/spec/Memio/Linter/CollectionCannotHaveNameDuplicatesSpec.php b/spec/Memio/Linter/CollectionCannotHaveNameDuplicatesSpec.php
new file mode 100644
index 0000000..50abd5a
--- /dev/null
+++ b/spec/Memio/Linter/CollectionCannotHaveNameDuplicatesSpec.php
@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Argument;
+use Memio\Model\Constant;
+use Memio\Model\Method;
+use Memio\Model\Property;
+use PhpSpec\ObjectBehavior;
+
+class CollectionCannotHaveNameDuplicatesSpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_unique_names(Argument $argument1, Argument $argument2)
+    {
+        $argument1->getName()->willReturn('myArgument1');
+        $argument2->getName()->willReturn('myArgument2');
+
+        $this->validate(array($argument1, $argument2))->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_with_name_duplicates(Argument $argument1, Argument $argument2)
+    {
+        $argument1->getName()->willReturn('myArgument');
+        $argument2->getName()->willReturn('myArgument');
+
+        $this->validate(array($argument1, $argument2))->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/spec/Memio/Linter/ConcreteObjectMethodsCannotBeAbstractSpec.php b/spec/Memio/Linter/ConcreteObjectMethodsCannotBeAbstractSpec.php
new file mode 100644
index 0000000..e5d6df4
--- /dev/null
+++ b/spec/Memio/Linter/ConcreteObjectMethodsCannotBeAbstractSpec.php
@@ -0,0 +1,52 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Object;
+use Memio\Model\Method;
+use PhpSpec\ObjectBehavior;
+
+class ConcreteObjectMethodsCannotBeAbstractSpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_concrete_object_and_concrete_methods(Object $object, Method $method)
+    {
+        $object->getName()->willReturn('ConcreteClass');
+        $object->isAbstract()->willReturn(false);
+        $object->allMethods()->willReturn(array($method));
+        $method->isAbstract()->willReturn(false);
+
+        $this->validate($object)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_fine_with_abstract_objects(Object $object)
+    {
+        $object->isAbstract()->willReturn(true);
+
+        $this->validate($object)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_with_concrete_object_and_abstract_methods(Object $object, Method $method)
+    {
+        $object->getName()->willReturn('ConcreteClass');
+        $object->isAbstract()->willReturn(false);
+        $object->allMethods()->willReturn(array($method));
+        $method->isAbstract()->willReturn(true);
+        $method->getName()->willReturn('abstractClass');
+
+        $this->validate($object)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/spec/Memio/Linter/ContractMethodsCanOnlyBePublicSpec.php b/spec/Memio/Linter/ContractMethodsCanOnlyBePublicSpec.php
new file mode 100644
index 0000000..24a4f46
--- /dev/null
+++ b/spec/Memio/Linter/ContractMethodsCanOnlyBePublicSpec.php
@@ -0,0 +1,62 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Contract;
+use Memio\Model\Method;
+use PhpSpec\ObjectBehavior;
+
+class ContractMethodsCanOnlyBePublicSpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_public_methods(Contract $contract, Method $method)
+    {
+        $contract->getName()->willReturn('HttpKernelInterface');
+        $contract->allMethods()->willReturn(array($method));
+        $method->getVisibility()->willReturn('public');
+
+        $this->validate($contract)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_fine_with_no_visibility_methods(Contract $contract, Method $method)
+    {
+        $contract->getName()->willReturn('HttpKernelInterface');
+        $contract->allMethods()->willReturn(array($method));
+        $method->getVisibility()->willReturn('');
+
+        $this->validate($contract)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_with_private_methods(Contract $contract, Method $method)
+    {
+        $contract->getName()->willReturn('HttpKernelInterface');
+        $contract->allMethods()->willReturn(array($method));
+        $method->getVisibility()->willReturn('private');
+        $method->getName()->willReturn('handle');
+
+        $this->validate($contract)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+
+    function it_is_not_fine_with_protected_methods(Contract $contract, Method $method)
+    {
+        $contract->getName()->willReturn('HttpKernelInterface');
+        $contract->allMethods()->willReturn(array($method));
+        $method->getVisibility()->willReturn('protected');
+        $method->getName()->willReturn('handle');
+
+        $this->validate($contract)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/spec/Memio/Linter/ContractMethodsCannotBeFinalSpec.php b/spec/Memio/Linter/ContractMethodsCannotBeFinalSpec.php
new file mode 100644
index 0000000..e9484aa
--- /dev/null
+++ b/spec/Memio/Linter/ContractMethodsCannotBeFinalSpec.php
@@ -0,0 +1,43 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Contract;
+use Memio\Model\Method;
+use PhpSpec\ObjectBehavior;
+
+class ContractMethodsCannotBeFinalSpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_simple_methods(Contract $contract, Method $method)
+    {
+        $contract->getName()->willReturn('HttpKernelInterface');
+        $contract->allMethods()->willReturn(array($method));
+        $method->isFinal()->willReturn(false);
+
+        $this->validate($contract)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_with_protected_methods(Contract $contract, Method $method)
+    {
+        $contract->getName()->willReturn('HttpKernelInterface');
+        $contract->allMethods()->willReturn(array($method));
+        $method->isFinal()->willReturn(true);
+        $method->getName()->willReturn('handle');
+
+        $this->validate($contract)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/spec/Memio/Linter/ContractMethodsCannotBeStaticSpec.php b/spec/Memio/Linter/ContractMethodsCannotBeStaticSpec.php
new file mode 100644
index 0000000..82f1558
--- /dev/null
+++ b/spec/Memio/Linter/ContractMethodsCannotBeStaticSpec.php
@@ -0,0 +1,43 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Contract;
+use Memio\Model\Method;
+use PhpSpec\ObjectBehavior;
+
+class ContractMethodsCannotBeStaticSpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_non_static_methods(Contract $contract, Method $method)
+    {
+        $contract->getName()->willReturn('HttpKernelInterface');
+        $contract->allMethods()->willReturn(array($method));
+        $method->isStatic()->willReturn(false);
+
+        $this->validate($contract)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_with_static_methods(Contract $contract, Method $method)
+    {
+        $contract->getName()->willReturn('HttpKernelInterface');
+        $contract->allMethods()->willReturn(array($method));
+        $method->isStatic()->willReturn(true);
+        $method->getName()->willReturn('handle');
+
+        $this->validate($contract)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/spec/Memio/Linter/ContractMethodsCannotHaveBodySpec.php b/spec/Memio/Linter/ContractMethodsCannotHaveBodySpec.php
new file mode 100644
index 0000000..87c5203
--- /dev/null
+++ b/spec/Memio/Linter/ContractMethodsCannotHaveBodySpec.php
@@ -0,0 +1,43 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Contract;
+use Memio\Model\Method;
+use PhpSpec\ObjectBehavior;
+
+class ContractMethodsCannotHaveBodySpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_pure_virtual_methods(Contract $contract, Method $method)
+    {
+        $contract->getName()->willReturn('HttpKernelInterface');
+        $contract->allMethods()->willReturn(array($method));
+        $method->getBody()->willReturn(null);
+
+        $this->validate($contract)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_none_pure_virtual_methods(Contract $contract, Method $method)
+    {
+        $contract->getName()->willReturn('HttpKernelInterface');
+        $contract->allMethods()->willReturn(array($method));
+        $method->getBody()->willReturn('echo "Nobody expects the spanish inquisition";');
+        $method->getName()->willReturn('handle');
+
+        $this->validate($contract)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/spec/Memio/Linter/MethodCannotBeAbstractAndHaveBodySpec.php b/spec/Memio/Linter/MethodCannotBeAbstractAndHaveBodySpec.php
new file mode 100644
index 0000000..44337ef
--- /dev/null
+++ b/spec/Memio/Linter/MethodCannotBeAbstractAndHaveBodySpec.php
@@ -0,0 +1,48 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Method;
+use PhpSpec\ObjectBehavior;
+
+class MethodCannotBeAbstractAndHaveBodySpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_simple_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(false);
+        $method->getBody()->willReturn('');
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_fine_with_abstract_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(true);
+        $method->getBody()->willReturn(null);
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_with_abstract_methods_with_body(Method $method)
+    {
+        $method->isAbstract()->willReturn(true);
+        $method->getBody()->willReturn('');
+        $method->getName()->willReturn('__construct');
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/spec/Memio/Linter/MethodCannotBeBothAbstractAndFinalSpec.php b/spec/Memio/Linter/MethodCannotBeBothAbstractAndFinalSpec.php
new file mode 100644
index 0000000..9600076
--- /dev/null
+++ b/spec/Memio/Linter/MethodCannotBeBothAbstractAndFinalSpec.php
@@ -0,0 +1,56 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Method;
+use PhpSpec\ObjectBehavior;
+
+class MethodCannotBeBothAbstractAndFinalSpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_simple_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(false);
+        $method->isFinal()->willReturn(false);
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_fine_with_abstract_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(true);
+        $method->isFinal()->willReturn(false);
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_fine_with_final_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(false);
+        $method->isFinal()->willReturn(true);
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_with_abstract_and_final_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(true);
+        $method->isFinal()->willReturn(true);
+        $method->getName()->willReturn('__construct');
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/spec/Memio/Linter/MethodCannotBeBothAbstractAndPrivateSpec.php b/spec/Memio/Linter/MethodCannotBeBothAbstractAndPrivateSpec.php
new file mode 100644
index 0000000..2d4a417
--- /dev/null
+++ b/spec/Memio/Linter/MethodCannotBeBothAbstractAndPrivateSpec.php
@@ -0,0 +1,48 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Method;
+use PhpSpec\ObjectBehavior;
+
+class MethodCannotBeBothAbstractAndPrivateSpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_abstract_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(true);
+        $method->getVisibility()->willReturn('public');
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_fine_with_private_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(false);
+        $method->getVisibility()->willReturn('private');
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_with_abstract_and_private_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(true);
+        $method->getVisibility()->willReturn('private');
+        $method->getName()->willReturn('__construct');
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/spec/Memio/Linter/MethodCannotBeBothAbstractAndStaticSpec.php b/spec/Memio/Linter/MethodCannotBeBothAbstractAndStaticSpec.php
new file mode 100644
index 0000000..fbe61da
--- /dev/null
+++ b/spec/Memio/Linter/MethodCannotBeBothAbstractAndStaticSpec.php
@@ -0,0 +1,40 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Method;
+use PhpSpec\ObjectBehavior;
+
+class MethodCannotBeBothAbstractAndStaticSpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_non_static_abstract_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(true);
+        $method->isStatic()->willReturn(false);
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_with_abstract_and_static_methods(Method $method)
+    {
+        $method->isAbstract()->willReturn(true);
+        $method->isStatic()->willReturn(true);
+        $method->getName()->willReturn('__construct');
+
+        $this->validate($method)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/spec/Memio/Linter/ObjectArgumentCanOnlyDefaultToNullSpec.php b/spec/Memio/Linter/ObjectArgumentCanOnlyDefaultToNullSpec.php
new file mode 100644
index 0000000..2d57acc
--- /dev/null
+++ b/spec/Memio/Linter/ObjectArgumentCanOnlyDefaultToNullSpec.php
@@ -0,0 +1,59 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace spec\Memio\Linter;
+
+use Memio\Model\Argument;
+use Memio\Model\Constant;
+use Memio\Model\Method;
+use Memio\Model\Property;
+use PhpSpec\ObjectBehavior;
+
+class ObjectArgumentCanOnlyDefaultToNullSpec extends ObjectBehavior
+{
+    function it_is_a_constraint()
+    {
+        $this->shouldImplement('Memio\Validator\Constraint');
+    }
+
+    function it_is_fine_with_scalar_arguments(Argument $argument)
+    {
+        $argument->getType()->willReturn('string');
+        $argument->getDefaultValue()->willReturn(null);
+
+        $this->validate($argument)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_fine_with_object_argument_without_default_value(Argument $argument)
+    {
+        $argument->getType()->willReturn('DateTime');
+        $argument->getDefaultValue()->willReturn(null);
+
+        $this->validate($argument)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_fine_with_object_argument_defaulting_to_null(Argument $argument)
+    {
+        $argument->getType()->willReturn('DateTime');
+        $argument->getDefaultValue()->willReturn('null');
+
+        $this->validate($argument)->shouldHaveType('Memio\Validator\Violation\NoneViolation');
+    }
+
+    function it_is_not_fine_with_object_argument_not_defaulting_to_null(Argument $argument)
+    {
+        $argument->getType()->willReturn('DateTime');
+        $argument->getDefaultValue()->willReturn('""');
+        $argument->getName()->willReturn('objectArgument');
+
+        $this->validate($argument)->shouldHaveType('Memio\Validator\Violation\SomeViolation');
+    }
+}
diff --git a/src/Memio/Linter/CollectionCannotHaveNameDuplicates.php b/src/Memio/Linter/CollectionCannotHaveNameDuplicates.php
new file mode 100644
index 0000000..f4041c6
--- /dev/null
+++ b/src/Memio/Linter/CollectionCannotHaveNameDuplicates.php
@@ -0,0 +1,43 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Model\FullyQualifiedName;
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class CollectionCannotHaveNameDuplicates implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        $firstElement = current($model);
+        $fqcn = get_class($firstElement);
+        $modelType = FullyQualifiedName::make($fqcn)->getName();
+        $nameCount = array();
+        foreach ($model as $element) {
+            $name = $element->getName();
+            $nameCount[$name] = isset($nameCount[$name]) ? $nameCount[$name] + 1 : 1;
+        }
+        $messages = array();
+        foreach ($nameCount as $name => $count) {
+            if ($count > 1) {
+                $messages[] = sprintf('Collection "%s" cannot have name "%s" duplicates (%s occurences)', $modelType, $name, $count);
+            }
+        }
+
+        return (empty($messages) ? new NoneViolation() : new SomeViolation(implode("\n", $messages)));
+    }
+}
diff --git a/src/Memio/Linter/ConcreteObjectMethodsCannotBeAbstract.php b/src/Memio/Linter/ConcreteObjectMethodsCannotBeAbstract.php
new file mode 100644
index 0000000..cd5a542
--- /dev/null
+++ b/src/Memio/Linter/ConcreteObjectMethodsCannotBeAbstract.php
@@ -0,0 +1,38 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class ConcreteObjectMethodsCannotBeAbstract implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        if ($model->isAbstract()) {
+            return new NoneViolation();
+        }
+        $objectName = $model->getName();
+        $messages = array();
+        foreach ($model->allMethods() as $method) {
+            if ($method->isAbstract()) {
+                $messages[] = sprintf('Concrete Object "%s" Method "%s" cannot be abstract', $objectName, $method->getName());
+            }
+        }
+
+        return (empty($messages) ? new NoneViolation() : new SomeViolation(implode("\n", $messages)));
+    }
+}
diff --git a/src/Memio/Linter/ContractMethodsCanOnlyBePublic.php b/src/Memio/Linter/ContractMethodsCanOnlyBePublic.php
new file mode 100644
index 0000000..7c5b344
--- /dev/null
+++ b/src/Memio/Linter/ContractMethodsCanOnlyBePublic.php
@@ -0,0 +1,36 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class ContractMethodsCanOnlyBePublic implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        $contractName = $model->getName();
+        $messages = array();
+        foreach ($model->allMethods() as $method) {
+            $visibility = $method->getVisibility();
+            if ('' !== $visibility && 'public' !== $visibility) {
+                $messages[] = sprintf('Contract "%s" Method "%s" can only be public', $contractName, $method->getName());
+            }
+        }
+
+        return (empty($messages) ? new NoneViolation() : new SomeViolation(implode("\n", $messages)));
+    }
+}
diff --git a/src/Memio/Linter/ContractMethodsCannotBeFinal.php b/src/Memio/Linter/ContractMethodsCannotBeFinal.php
new file mode 100644
index 0000000..3fe5d57
--- /dev/null
+++ b/src/Memio/Linter/ContractMethodsCannotBeFinal.php
@@ -0,0 +1,35 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class ContractMethodsCannotBeFinal implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        $contractName = $model->getName();
+        $messages = array();
+        foreach ($model->allMethods() as $method) {
+            if ($method->isFinal()) {
+                $messages[] = sprintf('Contract "%s" Method "%s" cannot be final', $contractName, $method->getName());
+            }
+        }
+
+        return (empty($messages) ? new NoneViolation() : new SomeViolation(implode("\n", $messages)));
+    }
+}
diff --git a/src/Memio/Linter/ContractMethodsCannotBeStatic.php b/src/Memio/Linter/ContractMethodsCannotBeStatic.php
new file mode 100644
index 0000000..9de47a8
--- /dev/null
+++ b/src/Memio/Linter/ContractMethodsCannotBeStatic.php
@@ -0,0 +1,35 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class ContractMethodsCannotBeStatic implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        $contractName = $model->getName();
+        $messages = array();
+        foreach ($model->allMethods() as $method) {
+            if ($method->isStatic()) {
+                $messages[] = sprintf('Contract "%s" Method "%s" cannot be static', $contractName, $method->getName());
+            }
+        }
+
+        return (empty($messages) ? new NoneViolation() : new SomeViolation(implode("\n", $messages)));
+    }
+}
diff --git a/src/Memio/Linter/ContractMethodsCannotHaveBody.php b/src/Memio/Linter/ContractMethodsCannotHaveBody.php
new file mode 100644
index 0000000..c303236
--- /dev/null
+++ b/src/Memio/Linter/ContractMethodsCannotHaveBody.php
@@ -0,0 +1,35 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class ContractMethodsCannotHaveBody implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        $contractName = $model->getName();
+        $messages = array();
+        foreach ($model->allMethods() as $method) {
+            if (null !== $method->getBody()) {
+                $messages[] = sprintf('Contract "%s" Method "%s" cannot have a body', $contractName, $method->getName());
+            }
+        }
+
+        return (empty($messages) ? new NoneViolation() : new SomeViolation(implode("\n", $messages)));
+    }
+}
diff --git a/src/Memio/Linter/MethodCannotBeAbstractAndHaveBody.php b/src/Memio/Linter/MethodCannotBeAbstractAndHaveBody.php
new file mode 100644
index 0000000..85004ea
--- /dev/null
+++ b/src/Memio/Linter/MethodCannotBeAbstractAndHaveBody.php
@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class MethodCannotBeAbstractAndHaveBody implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        if ($model->isAbstract() && null !== $model->getBody()) {
+            return new SomeViolation(sprintf('Method "%s" cannot be abstract and have a body', $model->getName()));
+        }
+
+        return new NoneViolation();
+    }
+}
diff --git a/src/Memio/Linter/MethodCannotBeBothAbstractAndFinal.php b/src/Memio/Linter/MethodCannotBeBothAbstractAndFinal.php
new file mode 100644
index 0000000..1c2bc61
--- /dev/null
+++ b/src/Memio/Linter/MethodCannotBeBothAbstractAndFinal.php
@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class MethodCannotBeBothAbstractAndFinal implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        if ($model->isAbstract() && $model->isFinal()) {
+            return new SomeViolation(sprintf('Method "%s" cannot be both abstract and final', $model->getName()));
+        }
+
+        return new NoneViolation();
+    }
+}
diff --git a/src/Memio/Linter/MethodCannotBeBothAbstractAndPrivate.php b/src/Memio/Linter/MethodCannotBeBothAbstractAndPrivate.php
new file mode 100644
index 0000000..e882711
--- /dev/null
+++ b/src/Memio/Linter/MethodCannotBeBothAbstractAndPrivate.php
@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class MethodCannotBeBothAbstractAndPrivate implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        if ($model->isAbstract() && 'private' === $model->getVisibility()) {
+            return new SomeViolation(sprintf('Method "%s" cannot be both abstract and private', $model->getName()));
+        }
+
+        return new NoneViolation();
+    }
+}
diff --git a/src/Memio/Linter/MethodCannotBeBothAbstractAndStatic.php b/src/Memio/Linter/MethodCannotBeBothAbstractAndStatic.php
new file mode 100644
index 0000000..4d47af2
--- /dev/null
+++ b/src/Memio/Linter/MethodCannotBeBothAbstractAndStatic.php
@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class MethodCannotBeBothAbstractAndStatic implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        if ($model->isAbstract() && $model->isStatic()) {
+            return new SomeViolation(sprintf('Method "%s" cannot be both abstract and static', $model->getName()));
+        }
+
+        return new NoneViolation();
+    }
+}
diff --git a/src/Memio/Linter/ObjectArgumentCanOnlyDefaultToNull.php b/src/Memio/Linter/ObjectArgumentCanOnlyDefaultToNull.php
new file mode 100644
index 0000000..d6dba4e
--- /dev/null
+++ b/src/Memio/Linter/ObjectArgumentCanOnlyDefaultToNull.php
@@ -0,0 +1,34 @@
+<?php
+
+/*
+ * This file is part of the memio/linter package.
+ *
+ * (c) Loïc Chardonnet <loic.chardonnet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Memio\Linter;
+
+use Memio\Model\Type;
+use Memio\Validator\Constraint;
+use Memio\Validator\Violation\NoneViolation;
+use Memio\Validator\Violation\SomeViolation;
+
+class ObjectArgumentCanOnlyDefaultToNull implements Constraint
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function validate($model)
+    {
+        $type = new Type($model->getType());
+        $defaultValue = $model->getDefaultValue();
+        if (!$type->isObject() || null === $defaultValue || 'null' === $defaultValue) {
+            return new NoneViolation();
+        }
+
+        return new SomeViolation(sprintf('Object Argument "%s" can only default to null', $model->getName()));
+    }
+}