diff --git a/doc/org.eclipse.emf.parsley.doc.websitegen/src/org/eclipse/emf/parsley/doc/websitegen/generator/AbstractWebsite.xtend b/doc/org.eclipse.emf.parsley.doc.websitegen/src/org/eclipse/emf/parsley/doc/websitegen/generator/AbstractWebsite.xtend
index 0c36d0f7..2a1d43f9 100644
--- a/doc/org.eclipse.emf.parsley.doc.websitegen/src/org/eclipse/emf/parsley/doc/websitegen/generator/AbstractWebsite.xtend
+++ b/doc/org.eclipse.emf.parsley.doc.websitegen/src/org/eclipse/emf/parsley/doc/websitegen/generator/AbstractWebsite.xtend
@@ -231,7 +231,7 @@ abstract class AbstractWebsite implements Resource {
 					<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-4">
 						<ul class="nav navbar-nav miolifooter">
 							«FOR it : topLevelMenu»
-								<li«IF equals(topLevelMenu.last)» style="border-right: 0 none;"«ENDIF»><a href="«key»">«value»</a></li>
+								<li«IF equals(topLevelMenu.lastOrNull)» style="border-right: 0 none;"«ENDIF»><a href="«key»">«value»</a></li>
 							«ENDFOR»
 						</ul>
 					</div><!-- /.navbar-collapse -->
diff --git a/dsl/org.eclipse.emf.parsley.dsl.tests/src/org/eclipse/emf/parsley/dsl/tests/EmfParsleyDslPluginXmlLoaderTest.xtend b/dsl/org.eclipse.emf.parsley.dsl.tests/src/org/eclipse/emf/parsley/dsl/tests/EmfParsleyDslPluginXmlLoaderTest.xtend
index d10d2ee7..9774b3c8 100644
--- a/dsl/org.eclipse.emf.parsley.dsl.tests/src/org/eclipse/emf/parsley/dsl/tests/EmfParsleyDslPluginXmlLoaderTest.xtend
+++ b/dsl/org.eclipse.emf.parsley.dsl.tests/src/org/eclipse/emf/parsley/dsl/tests/EmfParsleyDslPluginXmlLoaderTest.xtend
@@ -220,7 +220,7 @@ contentTypeId=org.eclipse.emf.ecore.xmi
 		val loader = load(s1)
 		val elements = loader.extensionElements
 		VIEW_POINT.assertEquals(loader.getElementExtension(elements.head))
-		EDITOR_POINT.assertEquals(loader.getElementExtension(elements.last))
+		EDITOR_POINT.assertEquals(loader.getElementExtension(elements.lastOrNull))
 	}
 
 	@Test
@@ -262,7 +262,7 @@ contentTypeId=org.eclipse.emf.ecore.xmi
 <extension
       point="org.eclipse.ui.editors">
 </extension>'''.toString.
-		assertEquals(loader.extensionNodes.last.toString)
+		assertEquals(loader.extensionNodes.lastOrNull.toString)
 	}
 
 	@Test
@@ -434,7 +434,7 @@ contentTypeId=org.eclipse.emf.ecore.xmi
 		val loader = load(singleView)
 		loader.insertExtensionElement(VIEW_POINT, "view")
 		'''<view></view>'''.toString.
-		assertEquals(loader.extensionElements.last.toString)
+		assertEquals(loader.extensionElements.lastOrNull.toString)
 	}
 
 	@Test
@@ -442,7 +442,7 @@ contentTypeId=org.eclipse.emf.ecore.xmi
 		val loader = load(emptyPlugin)
 		loader.insertExtensionElement(VIEW_POINT, "view")
 		'''<view></view>'''.toString.
-		assertEquals(loader.extensionElements.last.toString)
+		assertEquals(loader.extensionElements.lastOrNull.toString)
 	}
 
 	@Test
diff --git a/tests/org.eclipse.emf.parsley.tests/src/org/eclipse/emf/parsley/tests/AbstractEditingMenuBuilderTest.xtend b/tests/org.eclipse.emf.parsley.tests/src/org/eclipse/emf/parsley/tests/AbstractEditingMenuBuilderTest.xtend
index 1eef185a..974606b4 100644
--- a/tests/org.eclipse.emf.parsley.tests/src/org/eclipse/emf/parsley/tests/AbstractEditingMenuBuilderTest.xtend
+++ b/tests/org.eclipse.emf.parsley.tests/src/org/eclipse/emf/parsley/tests/AbstractEditingMenuBuilderTest.xtend
@@ -741,7 +741,7 @@ abstract class AbstractEditingMenuBuilderTest extends AbstractEmfParsleyTest {
 			executeAction("New Book for Writer")
 
 		// the book's library is not the original one
-		val addedLibrary = resource.contents.last as Library
+		val addedLibrary = resource.contents.lastOrNull as Library
 		val addedBook = addedLibrary.getAddedNewBook
 		addedBook.author.assertSame(writerForMenu)
 
diff --git a/tests/org.eclipse.emf.parsley.tests/src/org/eclipse/emf/parsley/tests/DatabindingValidationUtilTest.xtend b/tests/org.eclipse.emf.parsley.tests/src/org/eclipse/emf/parsley/tests/DatabindingValidationUtilTest.xtend
index cc0f0d86..f2eab5fe 100644
--- a/tests/org.eclipse.emf.parsley.tests/src/org/eclipse/emf/parsley/tests/DatabindingValidationUtilTest.xtend
+++ b/tests/org.eclipse.emf.parsley.tests/src/org/eclipse/emf/parsley/tests/DatabindingValidationUtilTest.xtend
@@ -62,7 +62,7 @@ class DatabindingValidationUtilTest extends AbstractEmfParsleyTest {
 				notEmpty = "foo"
 			]
 		]
-		fixture.getDiagnostic(container.objectsForDefaultValidation.last,
+		fixture.getDiagnostic(container.objectsForDefaultValidation.lastOrNull,
 			testPackage.classForDefaultValidation_NotEmpty).assertDiagnostic("")
 		fixture.getDiagnostic(container.objectsForDefaultValidation.head,
 			testPackage.classForDefaultValidation_NotEmpty).