diff --git a/src/Composer/Package/Link.php b/src/Composer/Package/Link.php
index 03ea3edff..16254f68e 100644
--- a/src/Composer/Package/Link.php
+++ b/src/Composer/Package/Link.php
@@ -56,11 +56,11 @@ class Link
      * @param string                   $description      Used to create a descriptive string representation
      * @param string|null              $prettyConstraint
      */
-    public function __construct($source, $target, ConstraintInterface $constraint = null, $description = 'relates to', $prettyConstraint = null)
+    public function __construct($source, $target, ConstraintInterface $constraint, $description = 'relates to', $prettyConstraint = null)
     {
         $this->source = strtolower($source);
         $this->target = strtolower($target);
-        $this->constraint = $constraint ? $constraint : new EmptyConstraint();
+        $this->constraint = $constraint;
         $this->description = $description;
         $this->prettyConstraint = $prettyConstraint;
     }
diff --git a/tests/Composer/Test/Autoload/AutoloadGeneratorTest.php b/tests/Composer/Test/Autoload/AutoloadGeneratorTest.php
index c178e93d8..896221c13 100644
--- a/tests/Composer/Test/Autoload/AutoloadGeneratorTest.php
+++ b/tests/Composer/Test/Autoload/AutoloadGeneratorTest.php
@@ -16,6 +16,7 @@ use Composer\Autoload\AutoloadGenerator;
 use Composer\Package\Link;
 use Composer\Package\Version\VersionParser;
 use Composer\Semver\Constraint\Constraint;
+use Composer\Semver\Constraint\EmptyConstraint;
 use Composer\Util\Filesystem;
 use Composer\Package\AliasPackage;
 use Composer\Package\Package;
@@ -366,8 +367,8 @@ class AutoloadGeneratorTest extends TestCase
     {
         $package = new Package('a', '1.0', '1.0');
         $package->setRequires(array(
-            new Link('a', 'a/a'),
-            new Link('a', 'b/b'),
+            new Link('a', 'a/a', new EmptyConstraint()),
+            new Link('a', 'b/b', new EmptyConstraint()),
         ));
 
         $packages = array();
@@ -395,7 +396,7 @@ class AutoloadGeneratorTest extends TestCase
     {
         $package = new Package('a', '1.0', '1.0');
         $package->setRequires(array(
-            new Link('a', 'a/a'),
+            new Link('a', 'a/a', new EmptyConstraint()),
         ));
 
         $packages = array();
@@ -403,11 +404,11 @@ class AutoloadGeneratorTest extends TestCase
         $packages[] = $b = new Package('b/b', '1.0', '1.0');
         $a->setAutoload(array('psr-0' => array('A' => 'src/', 'A\\B' => 'lib/')));
         $a->setRequires(array(
-            new Link('a/a', 'b/b'),
+            new Link('a/a', 'b/b', new EmptyConstraint()),
         ));
         $b->setAutoload(array('psr-0' => array('B\\Sub\\Name' => 'src/')));
         $b->setRequires(array(
-            new Link('b/b', 'a/a'),
+            new Link('b/b', 'a/a', new EmptyConstraint()),
         ));
 
         $this->repository->expects($this->once())
@@ -427,13 +428,13 @@ class AutoloadGeneratorTest extends TestCase
     public function testNonDevAutoloadShouldIncludeReplacedPackages()
     {
         $package = new Package('a', '1.0', '1.0');
-        $package->setRequires(array(new Link('a', 'a/a')));
+        $package->setRequires(array(new Link('a', 'a/a', new EmptyConstraint())));
 
         $packages = array();
         $packages[] = $a = new Package('a/a', '1.0', '1.0');
         $packages[] = $b = new Package('b/b', '1.0', '1.0');
 
-        $a->setRequires(array(new Link('a/a', 'b/c')));
+        $a->setRequires(array(new Link('a/a', 'b/c', new EmptyConstraint())));
 
         $b->setAutoload(array('psr-4' => array('B\\' => 'src/')));
         $b->setReplaces(
@@ -462,7 +463,7 @@ class AutoloadGeneratorTest extends TestCase
     {
         $package = new Package('a', '1.0', '1.0');
         $package->setRequires(array(
-            new Link('a', 'a/a'),
+            new Link('a', 'a/a', new EmptyConstraint()),
         ));
 
         $packages = array();
@@ -470,11 +471,11 @@ class AutoloadGeneratorTest extends TestCase
         $packages[] = $b = new Package('b/b', '1.0', '1.0');
         $a->setAutoload(array('psr-0' => array('A' => 'src/', 'A\\B' => 'lib/')));
         $a->setRequires(array(
-            new Link('a/a', 'c/c'),
+            new Link('a/a', 'c/c', new EmptyConstraint()),
         ));
         $b->setAutoload(array('psr-0' => array('B\\Sub\\Name' => 'src/')));
         $b->setReplaces(array(
-            new Link('b/b', 'c/c'),
+            new Link('b/b', 'c/c', new EmptyConstraint()),
         ));
 
         $this->repository->expects($this->once())
@@ -495,7 +496,7 @@ class AutoloadGeneratorTest extends TestCase
     {
         $package = new Package('a', '1.0', '1.0');
         $package->setRequires(array(
-            new Link('a', 'a/a')
+            new Link('a', 'a/a', new EmptyConstraint())
         ));
 
         $packages = array();
@@ -506,18 +507,18 @@ class AutoloadGeneratorTest extends TestCase
         $packages[] = $e = new Package('e/e', '1.0', '1.0');
         $a->setAutoload(array('classmap' => array('src/A.php')));
         $a->setRequires(array(
-            new Link('a/a', 'b/b')
+            new Link('a/a', 'b/b', new EmptyConstraint())
         ));
         $b->setAutoload(array('classmap' => array('src/B.php')));
         $b->setRequires(array(
-            new Link('b/b', 'e/e')
+            new Link('b/b', 'e/e', new EmptyConstraint())
         ));
         $c->setAutoload(array('classmap' => array('src/C.php')));
         $c->setReplaces(array(
-            new Link('c/c', 'b/b')
+            new Link('c/c', 'b/b', new EmptyConstraint())
         ));
         $c->setRequires(array(
-            new Link('c/c', 'd/d')
+            new Link('c/c', 'd/d', new EmptyConstraint())
         ));
         $d->setAutoload(array('classmap' => array('src/D.php')));
         $e->setAutoload(array('classmap' => array('src/E.php')));
@@ -547,7 +548,7 @@ class AutoloadGeneratorTest extends TestCase
     {
         $package = new Package('a', '1.0', '1.0');
         $package->setRequires(array(
-            new Link('a', 'a/a'),
+            new Link('a', 'a/a', new EmptyConstraint()),
         ));
 
         $package->setAutoload(array(
@@ -652,8 +653,8 @@ EOF;
     {
         $package = new Package('a', '1.0', '1.0');
         $package->setRequires(array(
-            new Link('a', 'a/a'),
-            new Link('a', 'b/b'),
+            new Link('a', 'a/a', new EmptyConstraint()),
+            new Link('a', 'b/b', new EmptyConstraint()),
         ));
 
         $packages = array();
@@ -692,8 +693,8 @@ EOF;
     {
         $package = new Package('a', '1.0', '1.0');
         $package->setRequires(array(
-            new Link('a', 'a/a'),
-            new Link('a', 'b/b'),
+            new Link('a', 'a/a', new EmptyConstraint()),
+            new Link('a', 'b/b', new EmptyConstraint()),
         ));
 
         $packages = array();
@@ -732,9 +733,9 @@ EOF;
     {
         $package = new Package('a', '1.0', '1.0');
         $package->setRequires(array(
-            new Link('a', 'a/a'),
-            new Link('a', 'b/b'),
-            new Link('a', 'c/c'),
+            new Link('a', 'a/a', new EmptyConstraint()),
+            new Link('a', 'b/b', new EmptyConstraint()),
+            new Link('a', 'c/c', new EmptyConstraint()),
         ));
 
         $packages = array();
@@ -777,9 +778,9 @@ EOF;
     {
         $package = new Package('a', '1.0', '1.0');
         $package->setRequires(array(
-            new Link('a', 'a/a'),
-            new Link('a', 'b/b'),
-            new Link('a', 'c/c'),
+            new Link('a', 'a/a', new EmptyConstraint()),
+            new Link('a', 'b/b', new EmptyConstraint()),
+            new Link('a', 'c/c', new EmptyConstraint()),
         ));
 
         $packages = array();
@@ -827,9 +828,9 @@ EOF;
         $package = new Package('a', '1.0', '1.0');
         $package->setAutoload(array('files' => array('root.php')));
         $package->setRequires(array(
-            new Link('a', 'a/a'),
-            new Link('a', 'b/b'),
-            new Link('a', 'c/c'),
+            new Link('a', 'a/a', new EmptyConstraint()),
+            new Link('a', 'b/b', new EmptyConstraint()),
+            new Link('a', 'c/c', new EmptyConstraint()),
         ));
 
         $packages = array();
@@ -878,9 +879,9 @@ EOF;
         $notAutoloadPackage = new Package('a', '1.0', '1.0');
 
         $requires = array(
-            new Link('a', 'a/a'),
-            new Link('a', 'b/b'),
-            new Link('a', 'c/c'),
+            new Link('a', 'a/a', new EmptyConstraint()),
+            new Link('a', 'b/b', new EmptyConstraint()),
+            new Link('a', 'c/c', new EmptyConstraint()),
         );
         $autoloadPackage->setRequires($requires);
         $notAutoloadPackage->setRequires($requires);
@@ -949,10 +950,10 @@ EOF;
         $package = new Package('a', '1.0', '1.0');
         $package->setAutoload(array('files' => array('root2.php')));
         $package->setRequires(array(
-            new Link('a', 'z/foo'),
-            new Link('a', 'b/bar'),
-            new Link('a', 'd/d'),
-            new Link('a', 'e/e'),
+            new Link('a', 'z/foo', new EmptyConstraint()),
+            new Link('a', 'b/bar', new EmptyConstraint()),
+            new Link('a', 'd/d', new EmptyConstraint()),
+            new Link('a', 'e/e', new EmptyConstraint()),
         ));
 
         $packages = array();
@@ -963,18 +964,18 @@ EOF;
         $packages[] = $e = new Package('e/e', '1.0', '1.0');
 
         $z->setAutoload(array('files' => array('testA.php')));
-        $z->setRequires(array(new Link('z/foo', 'c/lorem')));
+        $z->setRequires(array(new Link('z/foo', 'c/lorem', new EmptyConstraint())));
 
         $b->setAutoload(array('files' => array('testB.php')));
-        $b->setRequires(array(new Link('b/bar', 'c/lorem'), new Link('b/bar', 'd/d')));
+        $b->setRequires(array(new Link('b/bar', 'c/lorem', new EmptyConstraint()), new Link('b/bar', 'd/d', new EmptyConstraint())));
 
         $c->setAutoload(array('files' => array('testC.php')));
 
         $d->setAutoload(array('files' => array('testD.php')));
-        $d->setRequires(array(new Link('d/d', 'c/lorem')));
+        $d->setRequires(array(new Link('d/d', 'c/lorem', new EmptyConstraint())));
 
         $e->setAutoload(array('files' => array('testE.php')));
-        $e->setRequires(array(new Link('e/e', 'c/lorem')));
+        $e->setRequires(array(new Link('e/e', 'c/lorem', new EmptyConstraint())));
 
         $this->repository->expects($this->once())
             ->method('getCanonicalPackages')
@@ -1022,8 +1023,8 @@ EOF;
             'classmap' => array($this->workingDir.'/src'),
         ));
         $mainPackage->setRequires(array(
-            new Link('z', 'a/a'),
-            new Link('z', 'b/b'),
+            new Link('z', 'a/a', new EmptyConstraint()),
+            new Link('z', 'b/b', new EmptyConstraint()),
         ));
 
         $packages = array();
@@ -1285,7 +1286,7 @@ EOF;
             'files' => array('test.php'),
         ));
         $package->setRequires(array(
-            new Link('a', 'b/b'),
+            new Link('a', 'b/b', new EmptyConstraint()),
         ));
 
         $vendorPackage = new Package('b/b', '1.0', '1.0');
diff --git a/tests/Composer/Test/DependencyResolver/RuleTest.php b/tests/Composer/Test/DependencyResolver/RuleTest.php
index cd3b74887..0f2face8f 100644
--- a/tests/Composer/Test/DependencyResolver/RuleTest.php
+++ b/tests/Composer/Test/DependencyResolver/RuleTest.php
@@ -19,6 +19,7 @@ use Composer\DependencyResolver\Pool;
 use Composer\Package\BasePackage;
 use Composer\Package\Link;
 use Composer\Repository\ArrayRepository;
+use Composer\Semver\Constraint\EmptyConstraint;
 use Composer\Test\TestCase;
 
 class RuleTest extends TestCase
@@ -102,7 +103,7 @@ class RuleTest extends TestCase
         $repositorySetMock = $this->getMockBuilder('Composer\Repository\RepositorySet')->disableOriginalConstructor()->getMock();
         $requestMock = $this->getMockBuilder('Composer\DependencyResolver\Request')->disableOriginalConstructor()->getMock();
 
-        $rule = new GenericRule(array($p1->getId(), -$p2->getId()), Rule::RULE_PACKAGE_REQUIRES, new Link('baz', 'foo', 'relates to', '*'));
+        $rule = new GenericRule(array($p1->getId(), -$p2->getId()), Rule::RULE_PACKAGE_REQUIRES, new Link('baz', 'foo', new EmptyConstraint(), 'relates to', '*'));
 
         $this->assertEquals('baz 1.1 relates to foo * -> satisfiable by foo[2.1].', $rule->getPrettyString($repositorySetMock, $requestMock, $pool, false));
     }
diff --git a/tests/Composer/Test/DependencyResolver/SolverTest.php b/tests/Composer/Test/DependencyResolver/SolverTest.php
index 56d2d7e5b..a8f91910d 100644
--- a/tests/Composer/Test/DependencyResolver/SolverTest.php
+++ b/tests/Composer/Test/DependencyResolver/SolverTest.php
@@ -235,8 +235,8 @@ class SolverTest extends TestCase
         $this->repo->addPackage($newPackageA = $this->getPackage('A', '1.1'));
         $this->repo->addPackage($newPackageB = $this->getPackage('B', '1.1'));
 
-        $packageA->setRequires(array('b' => new Link('A', 'B', null, 'requires')));
-        $newPackageA->setRequires(array('b' => new Link('A', 'B', null, 'requires')));
+        $packageA->setRequires(array('b' => new Link('A', 'B', new EmptyConstraint(), 'requires')));
+        $newPackageA->setRequires(array('b' => new Link('A', 'B', new EmptyConstraint(), 'requires')));
 
         $this->reposComplete();
 
diff --git a/tests/Composer/Test/Package/RootAliasPackageTest.php b/tests/Composer/Test/Package/RootAliasPackageTest.php
index a5fe9172d..5cfcd7179 100644
--- a/tests/Composer/Test/Package/RootAliasPackageTest.php
+++ b/tests/Composer/Test/Package/RootAliasPackageTest.php
@@ -14,6 +14,7 @@ namespace Composer\Test\Package;
 
 use Composer\Package\Link;
 use Composer\Package\RootAliasPackage;
+use Composer\Semver\Constraint\EmptyConstraint;
 use Composer\Test\TestCase;
 use Prophecy\Argument;
 
@@ -26,7 +27,7 @@ class RootAliasPackageTest extends TestCase
 
         $alias = new RootAliasPackage($root->reveal(), '1.0', '1.0.0.0');
         $this->assertEmpty($alias->getRequires());
-        $links = array(new Link('a', 'b', null, 'foo', 'self.version'));
+        $links = array(new Link('a', 'b', new EmptyConstraint(), 'foo', 'self.version'));
         $alias->setRequires($links);
         $this->assertNotEmpty($alias->getRequires());
     }
@@ -38,7 +39,7 @@ class RootAliasPackageTest extends TestCase
 
         $alias = new RootAliasPackage($root->reveal(), '1.0', '1.0.0.0');
         $this->assertEmpty($alias->getDevRequires());
-        $links = array(new Link('a', 'b', null, 'foo', 'self.version'));
+        $links = array(new Link('a', 'b', new EmptyConstraint(), 'foo', 'self.version'));
         $alias->setDevRequires($links);
         $this->assertNotEmpty($alias->getDevRequires());
     }
@@ -50,7 +51,7 @@ class RootAliasPackageTest extends TestCase
 
         $alias = new RootAliasPackage($root->reveal(), '1.0', '1.0.0.0');
         $this->assertEmpty($alias->getConflicts());
-        $links = array(new Link('a', 'b', null, 'foo', 'self.version'));
+        $links = array(new Link('a', 'b', new EmptyConstraint(), 'foo', 'self.version'));
         $alias->setConflicts($links);
         $this->assertNotEmpty($alias->getConflicts());
     }
@@ -62,7 +63,7 @@ class RootAliasPackageTest extends TestCase
 
         $alias = new RootAliasPackage($root->reveal(), '1.0', '1.0.0.0');
         $this->assertEmpty($alias->getProvides());
-        $links = array(new Link('a', 'b', null, 'foo', 'self.version'));
+        $links = array(new Link('a', 'b', new EmptyConstraint(), 'foo', 'self.version'));
         $alias->setProvides($links);
         $this->assertNotEmpty($alias->getProvides());
     }
@@ -74,7 +75,7 @@ class RootAliasPackageTest extends TestCase
 
         $alias = new RootAliasPackage($root->reveal(), '1.0', '1.0.0.0');
         $this->assertEmpty($alias->getReplaces());
-        $links = array(new Link('a', 'b', null, 'foo', 'self.version'));
+        $links = array(new Link('a', 'b', new EmptyConstraint(), 'foo', 'self.version'));
         $alias->setReplaces($links);
         $this->assertNotEmpty($alias->getReplaces());
     }
diff --git a/tests/Composer/Test/Repository/InstalledRepositoryTest.php b/tests/Composer/Test/Repository/InstalledRepositoryTest.php
index a37adb058..4c63f0670 100644
--- a/tests/Composer/Test/Repository/InstalledRepositoryTest.php
+++ b/tests/Composer/Test/Repository/InstalledRepositoryTest.php
@@ -16,6 +16,7 @@ use Composer\Repository\InstalledRepository;
 use Composer\Repository\ArrayRepository;
 use Composer\Repository\InstalledArrayRepository;
 use Composer\Package\Link;
+use Composer\Semver\Constraint\EmptyConstraint;
 use Composer\Test\TestCase;
 
 class InstalledRepositoryTest extends TestCase
@@ -30,8 +31,8 @@ class InstalledRepositoryTest extends TestCase
         $arrayRepoTwo->addPackage($bar = $this->getPackage('bar', '1'));
         $arrayRepoTwo->addPackage($bar2 = $this->getPackage('bar', '2'));
 
-        $foo->setReplaces(array(new Link('foo', 'provided')));
-        $bar2->setProvides(array(new Link('bar', 'provided')));
+        $foo->setReplaces(array(new Link('foo', 'provided', new EmptyConstraint())));
+        $bar2->setProvides(array(new Link('bar', 'provided', new EmptyConstraint())));
 
         $repo = new InstalledRepository(array($arrayRepoOne, $arrayRepoTwo));