Add basic support for c++20 concepts and constraints

core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TestBase.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2004, 2016 IBM Corporation and others.
+ * Copyright (c) 2004, 2016, 2025 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -158,6 +158,7 @@ private static Map<String, String> getStdCpp20Map() {
 		Map<String, String> map = getStdMap();
 		map.put("__cpp_impl_three_way_comparison", "201907L");
 		map.put("__cpp_char8_t", "201811L");
+		map.put("__cpp_concepts", "201907L");
 		return map;
 	}
 

core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/cxx20/ConceptsTests.java

@@ -0,0 +1,139 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Igor V. Kovalenko.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Igor V. Kovalenko - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.core.parser.tests.ast2.cxx20;
+
+import org.eclipse.cdt.core.parser.tests.ast2.AST2CPPTestBase;
+
+/**
+ * AST tests for C++20 requires expressions.
+ */
+public class ConceptsTests extends AST2CPPTestBase {
+	//  template<typename T>
+	//  concept A = true;
+	//
+	//  template<typename T>
+	//  concept B = A<T>;
+	//
+	//  template<typename T>
+	//  concept C = requires {
+	//      true;
+	//  };
+	public void testConceptDefinitionExpressions() throws Exception {
+		parseAndCheckBindings(ScannerKind.STDCPP20);
+	}
+
+	//  template<typename T>
+	//  void x() requires true;
+	//
+	//  template<typename T>
+	//  void y() requires requires () {
+	//      true;
+	//  };
+	//
+	//  template<typename T>
+	//  void z() requires true && false;
+	public void testFunctionDeclarationTrailingRequiresClauseTrue() throws Exception {
+		parseAndCheckBindings(ScannerKind.STDCPP20);
+	}
+
+	//  template<typename T>
+	//  concept A = false;
+	//  template<typename T>
+	//  concept B = true;
+	//  template<typename T>
+	//  concept C = true;
+	//
+	//  template<typename T>
+	//  void x() requires true && false {}
+	//
+	//  template<typename T>
+	//  void x_c() requires C<T> {}
+	//
+	//  template<typename T>
+	//  void x_abc() requires A<T> || B<T> && C<T> {}
+	public void testFunctionDefinitionTrailingRequiresClause() throws Exception {
+		parseAndCheckBindings(ScannerKind.STDCPP20);
+	}
+
+	//  template<typename T>
+	//  concept A = false;
+	//  template<typename T>
+	//  concept B = true;
+	//  template<typename T>
+	//  concept C = true;
+	//
+	//  template<typename T>
+	//  requires A<T> || B<T> && C<T>
+	//  void x() {}
+	public void testTemplateHeadRequiresClause() throws Exception {
+		parseAndCheckBindings(ScannerKind.STDCPP20);
+	}
+
+	//  template<typename T>
+	//  requires requires { true; }
+	//  void x() {}
+	public void testTemplateHeadAdHocRequiresExpression() throws Exception {
+		parseAndCheckBindings(ScannerKind.STDCPP20);
+	}
+
+	//  template<typename T>
+	//  constexpr bool value = requires () { true; };
+	public void testInitializerRequiresExpression() throws Exception {
+		parseAndCheckBindings(ScannerKind.STDCPP20);
+	}
+
+	//  template<typename T>
+	//  constexpr bool x() {
+	//		if constexpr(requires { true; }) {
+	//			return true;
+	//		} else {
+	//			return false;
+	//		}
+	//	}
+	public void testConstexprIfRequiresExpression() throws Exception {
+		parseAndCheckBindings(ScannerKind.STDCPP20);
+	}
+
+	//  template<typename T>
+	//  concept A = false;
+	//  template<typename T>
+	//  concept B = true;
+	//  template<typename T>
+	//  concept C = true;
+	//
+	//  template<A U>
+	//  void f_a(U a_u);
+	//  template<A U1, B U2, C U3>
+	//  void f_abc(U1 a_u1, U2 b_u2, U3 c_u3);
+	public void testTemplateArgumentTypeConstraint() throws Exception {
+		parseAndCheckBindings(ScannerKind.STDCPP20);
+	}
+
+	//  template<typename T>
+	//  concept A = false;
+	//  namespace Outer {
+	//      template<typename T>
+	//      concept B = true;
+	//      namespace Inner {
+	//          template<typename T>
+	//          concept C = true;
+	//      }
+	//  }
+	//
+	//  template<A U1, Outer::B U2, Outer::Inner::C U3>
+	//  void f_abc(U1 a_u1, U2 b_u2, U3 c_u3);
+	public void testTemplateArgumentTypeConstraintFromNamespace() throws Exception {
+		parseAndCheckBindings(ScannerKind.STDCPP20);
+	}
+}

core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexConceptTest.java

@@ -0,0 +1,83 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Igor V. Kovalenko.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Igor V. Kovalenko - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.internal.index.tests;
+
+import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTConceptDefinition;
+import org.eclipse.cdt.core.dom.ast.cpp.ICPPConcept;
+import org.eclipse.cdt.core.testplugin.TestScannerProvider;
+
+import junit.framework.TestSuite;
+
+/**
+ * AST tests for C++20 concepts via PDOM.
+ */
+public abstract class IndexConceptTest extends IndexBindingResolutionTestBase {
+	public static class SingleProject extends IndexConceptTest {
+		public SingleProject() {
+			setStrategy(new SinglePDOMTestStrategy(true /* cpp */));
+		}
+
+		public static TestSuite suite() {
+			return suite(SingleProject.class);
+		}
+	}
+
+	public static class SingleProjectReindexed extends IndexConceptTest {
+		public SingleProjectReindexed() {
+			setStrategy(new SinglePDOMReindexedTestStrategy(true /* cpp */));
+		}
+
+		public static TestSuite suite() {
+			return suite(SingleProjectReindexed.class);
+		}
+	}
+
+	public static class ProjectWithDepProj extends IndexConceptTest {
+		public ProjectWithDepProj() {
+			setStrategy(new ReferencedProject(true /* cpp */));
+		}
+
+		public static TestSuite suite() {
+			return suite(ProjectWithDepProj.class);
+		}
+	}
+
+	private static void cxx20SetUp() {
+		TestScannerProvider.sDefinedSymbols.put("__cpp_concepts", "201907L");
+	}
+
+	@Override
+	public void setUp() throws Exception {
+		cxx20SetUp();
+		super.setUp();
+	}
+
+	public static void addTests(TestSuite suite) {
+		suite.addTest(SingleProject.suite());
+		suite.addTest(SingleProjectReindexed.suite());
+		suite.addTest(ProjectWithDepProj.suite());
+	}
+
+	//  template<typename T>
+	//  concept A = true;
+
+	//  template<typename T>
+	//  concept B = A<T>;
+	public void testConceptDefinitionFromHeader() throws Exception {
+		checkBindings();
+
+		ICPPConcept concept = getBindingFromASTName("B = A<T>", 1);
+		ICPPASTConceptDefinition decl = concept.getConceptDefinition();
+	}
+}

core/org.eclipse.cdt.core/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.cdt.core; singleton:=true
-Bundle-Version: 9.2.100.qualifier
+Bundle-Version: 9.3.0.qualifier
 Bundle-Activator: org.eclipse.cdt.core.CCorePlugin
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin

core/org.eclipse.cdt.core/browser/org/eclipse/cdt/internal/core/browser/IndexModelUtil.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2006, 2015 QNX Software Systems and others.
+ * Copyright (c) 2006, 2015, 2025 QNX Software Systems and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -32,6 +32,7 @@
 import org.eclipse.cdt.core.dom.ast.IVariable;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPAliasTemplate;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPClassType;
+import org.eclipse.cdt.core.dom.ast.cpp.ICPPConcept;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPNamespace;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPNamespaceAlias;
 import org.eclipse.cdt.core.index.IIndexMacroContainer;
@@ -91,6 +92,10 @@ public static boolean bindingHasCElementType(IBinding binding, int[] kinds) {
 				if (binding instanceof IEnumerator)
 					return true;
 				break;
+			case ICElement.C_CONCEPT:
+				if (binding instanceof ICPPConcept)
+					return true;
+				break;
 			}
 		}
 		return false;
@@ -152,6 +157,9 @@ public static int getElementType(IBinding binding) {
 		if (binding instanceof IParameter) {
 			elementType = ICElement.C_VARIABLE_LOCAL;
 		}
+		if (binding instanceof ICPPConcept) {
+			elementType = ICElement.C_CONCEPT;
+		}
 		return elementType;
 	}
 

core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/model/ICElement.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2014 QNX Software Systems and others.
+ * Copyright (c) 2000, 2014, 2025 QNX Software Systems and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -249,6 +249,12 @@ public interface ICElement extends IAdaptable {
 	 */
 	static final int C_PRAGMA = 95;
 
+	/**
+	 * a C++ concept.
+	 * @since 9.3
+	 */
+	static final int C_CONCEPT = 96;
+
 	/**
 	 * @deprecated use {@link IMethodDeclaration#isConstructor()}
 	 * @noreference This field is not intended to be referenced by clients.

core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/model/IConcept.java

@@ -0,0 +1,26 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Igor V. Kovalenko.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Igor V. Kovalenko - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.core.model;
+
+/**
+ * Represents a C++ concept.
+ *
+ * @noextend This interface is not intended to be extended by clients.
+ * @noimplement This interface is not intended to be implemented by clients.
+ *
+ * @since 9.3
+ */
+public interface IConcept extends IDeclaration, ITemplate {
+
+}