tests for Java 8 default methods

org.eclipse.xtext.xbase.tests/src/org/eclipse/xtext/xbase/tests/validation/JvmGenericTypeValidatorTest.java

@@ -400,6 +400,52 @@ public void testWildcardSuperType() throws Exception {
 				"does not override it");
 	}
 
+	@Test public void testConflictingDefaultMethods() throws Exception {
+		var source = "class C implements "
+				+ "test.InterfaceWithDefaultMethod1,"
+				+ "test.InterfaceWithDefaultMethod2 { }";
+		var model = parse(source);
+		validationHelper.assertError(model, MY_CLASS, CONFLICTING_DEFAULT_METHODS,
+			source.indexOf("C"), 1,
+			"The type C inherits multiple implementations of the method foo()"
+			+ " from InterfaceWithDefaultMethod1 and InterfaceWithDefaultMethod2.");
+	}
+
+	@Test public void testConflictingDefaultMethods00() throws Exception {
+		var source = "interface C extends "
+				+ "test.InterfaceWithDefaultMethod1,"
+				+ "test.InterfaceWithDefaultMethod2 { }";
+		var model = parse(source);
+		validationHelper.assertError(model, MY_INTERFACE, CONFLICTING_DEFAULT_METHODS,
+			source.indexOf("C"), 1,
+			"The type C inherits multiple implementations of the method foo()"
+			+ " from InterfaceWithDefaultMethod1 and InterfaceWithDefaultMethod2.");
+	}
+
+	@Test public void testConflictingDefaultMethods01() throws Exception {
+		var source = "class C implements "
+				+ "test.InterfaceWithDefaultMethod1,"
+				+ "test.InterfaceWithAbstractMethod { }";
+		var model = parse(source);
+		validationHelper.assertError(model, MY_CLASS, CONFLICTING_DEFAULT_METHODS,
+			source.indexOf("C"), 1,
+			"The non-abstract method foo() inherited from "
+			+ "InterfaceWithDefaultMethod1 conflicts with the method foo()"
+			+ " inherited from InterfaceWithAbstractMethod.");
+	}
+
+	@Test public void testConflictingDefaultMethods02() throws Exception {
+		var source = "class C implements "
+				+ "test.InterfaceWithAbstractMethod,"
+				+ "test.InterfaceWithDefaultMethod1 { }";
+		var model = parse(source);
+		validationHelper.assertError(model, MY_CLASS, CONFLICTING_DEFAULT_METHODS,
+			source.indexOf("C"), 1,
+			"The non-abstract method foo() inherited from "
+			+ "InterfaceWithDefaultMethod1 conflicts with the method foo()"
+			+ " inherited from InterfaceWithAbstractMethod.");
+	}
+
 	@Test public void testDuplicateParameter() throws Exception {
 		var source = "class Foo { def void foo(int x, int x) {} }";
 		var model = parse(source);

org.eclipse.xtext.xbase.tests/src/org/eclipse/xtext/xbase/tests/validation/JvmGenericTypeValidatorTestLangInjectorProviderCustom.java

@@ -8,17 +8,35 @@
  *******************************************************************************/
 package org.eclipse.xtext.xbase.tests.validation;
 
+import org.eclipse.xtext.util.JavaVersion;
+import org.eclipse.xtext.xbase.testing.JavaVersionModule;
 import org.eclipse.xtext.xbase.testlanguages.JvmGenericTypeValidatorTestLangRuntimeModule;
+import org.eclipse.xtext.xbase.testlanguages.JvmGenericTypeValidatorTestLangStandaloneSetup;
 import org.eclipse.xtext.xbase.testlanguages.tests.JvmGenericTypeValidatorTestLangInjectorProvider;
 
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+
 /**
  * To let the validator/scoping/linking find the Java classes of "testdata" referred in some tests also in an OSGI and Maven/Tycho
  * environment. This is required because the original {@link JvmGenericTypeValidatorTestLangInjectorProvider} is not in this bundle.
+ * Moreover, we configure Java 8.
  * 
  * @author Lorenzo Bettini - Initial contribution and API
  */
 public class JvmGenericTypeValidatorTestLangInjectorProviderCustom extends JvmGenericTypeValidatorTestLangInjectorProvider {
 
+	@Override
+	protected Injector internalCreateInjector() {
+		return new JvmGenericTypeValidatorTestLangStandaloneSetup() {
+			@Override
+			public Injector createInjector() {
+				return Guice.createInjector(createRuntimeModule(),
+						new JavaVersionModule(JavaVersion.JAVA8));
+			}
+		}.createInjectorAndDoEMFRegistration();
+	}
+
 	@Override
 	protected JvmGenericTypeValidatorTestLangRuntimeModule createRuntimeModule() {
 		// make it work also with Maven/Tycho and OSGI

org.eclipse.xtext.xbase.tests/testdata/test/InterfaceWithAbstractMethod.java

@@ -0,0 +1,16 @@
+/*******************************************************************************
+ * Copyright (c) 2024 itemis AG (http://www.itemis.eu) and others.
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package test;
+
+/**
+ * @author Lorenzo Bettini - Initial contribution and API
+ */
+public interface InterfaceWithAbstractMethod {
+	void foo();
+}

org.eclipse.xtext.xbase.tests/testdata/test/InterfaceWithDefaultMethod1.java

@@ -0,0 +1,17 @@
+/*******************************************************************************
+ * Copyright (c) 2024 itemis AG (http://www.itemis.eu) and others.
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package test;
+
+/**
+ * @author Lorenzo Bettini - Initial contribution and API
+ */
+public interface InterfaceWithDefaultMethod1 {
+	default void foo() {
+	}
+}

org.eclipse.xtext.xbase.tests/testdata/test/InterfaceWithDefaultMethod2.java

@@ -0,0 +1,17 @@
+/*******************************************************************************
+ * Copyright (c) 2024 itemis AG (http://www.itemis.eu) and others.
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package test;
+
+/**
+ * @author Lorenzo Bettini - Initial contribution and API
+ */
+public interface InterfaceWithDefaultMethod2 {
+	default void foo() {
+	}
+}