Bug 534420 - Add support for nodiscard attribute for class types

Change-Id: I7466301118bacc04029c315d97441ff8e56142b5

core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2CPPTests.java

@@ -145,15 +145,20 @@ import org.eclipse.cdt.core.dom.ast.cpp.ICPPVariable;
 import org.eclipse.cdt.core.dom.ast.cpp.SemanticQueries;
 import org.eclipse.cdt.core.parser.IProblem;
 import org.eclipse.cdt.core.parser.ParserLanguage;
+import org.eclipse.cdt.core.parser.util.AttributeUtil;
 import org.eclipse.cdt.core.parser.util.CharArrayUtils;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPASTNameBase;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPBasicType;
+import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPClassInstance;
+import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPClassTemplate;
+import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPClassTemplatePartialSpecialization;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPClassType;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPConstructor;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPFunctionType;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPMethod;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPPointerType;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPQualifierType;
+import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPVariable;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.ClassTypeHelper;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.ICPPInternalBinding;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.OverloadableOperator;
@@ -13426,4 +13431,74 @@ public class AST2CPPTests extends AST2CPPTestBase {
 		ICPPASTExpression f = helper.assertNode("f[] = \"waldo\"", "\"waldo\"");
 		assertTrue(e.getEvaluation().isEquivalentTo(f.getEvaluation()));
 	}
+
+	// struct Base {
+	// };
+	// struct [[nodiscard]] S : public Base {
+	// };
+	public void testNoDiscardClass_Bug534420() throws Exception {
+		String code = getAboveComment();
+		parseAndCheckBindings(code);
+
+		BindingAssertionHelper bh = new AST2AssertionHelper(code, true);
+
+		CPPClassType structBase = bh.assertNonProblem("Base {", 4);
+		assertFalse(structBase.isNoDiscard());
+		IASTNode baseDefinitionName = structBase.getDefinition();
+		IASTNode baseDefinition = baseDefinitionName.getParent();
+		assertInstance(baseDefinition, ICPPASTCompositeTypeSpecifier.class);
+		assertFalse(AttributeUtil.hasNodiscardAttribute(((ICPPASTCompositeTypeSpecifier) baseDefinition)));
+
+		CPPClassType structS = bh.assertNonProblem("S", 1);
+		assertTrue(structS.isNoDiscard());
+		IASTNode sDefinitionName = structS.getDefinition();
+		IASTNode sDefinition = sDefinitionName.getParent();
+		assertInstance(sDefinition, ICPPASTCompositeTypeSpecifier.class);
+		assertTrue(AttributeUtil.hasNodiscardAttribute(((ICPPASTCompositeTypeSpecifier) sDefinition)));
+	}
+
+	//template <typename T>
+	//struct Foo {};
+	//template <typename T>
+	//struct [[nodiscard]] Foo<T*> {};
+	//template <>
+	//struct [[nodiscard]] Foo<int> {};
+	//
+	//Foo<double> var1;
+	//Foo<int*> var2;
+	//Foo<int> var3;
+	public void testNoDiscardTemplateSpecialization_Bug534420() throws Exception {
+		String code = getAboveComment();
+		parseAndCheckBindings(code);
+
+		BindingAssertionHelper bh = new AST2AssertionHelper(code, true);
+
+		CPPClassTemplate structFoo = bh.assertNonProblem("Foo {", 3);
+		assertFalse(structFoo.isNoDiscard());
+		IASTNode fooDefinitionName = structFoo.getDefinition();
+		IASTNode fooDefinition = fooDefinitionName.getParent();
+		assertInstance(fooDefinition, ICPPASTCompositeTypeSpecifier.class);
+		assertFalse(AttributeUtil.hasNodiscardAttribute(((ICPPASTCompositeTypeSpecifier) fooDefinition)));
+
+		CPPClassTemplatePartialSpecialization structSpec = bh.assertNonProblem("Foo<T*> {", 7);
+		assertTrue(structSpec.isNoDiscard());
+		IASTNode specDefinitionName = structSpec.getDefinition();
+		IASTNode specDefinition = specDefinitionName.getParent();
+		assertInstance(specDefinition, ICPPASTCompositeTypeSpecifier.class);
+		assertTrue(AttributeUtil.hasNodiscardAttribute(((ICPPASTCompositeTypeSpecifier) specDefinition)));
+
+		CPPClassInstance structFullSpec = bh.assertNonProblem("Foo<int> {", 8);
+		assertTrue(structSpec.isNoDiscard());
+		IASTNode specFullDefinitionName = structFullSpec.getDefinition();
+		IASTNode specFullDefinition = specFullDefinitionName.getParent();
+		assertInstance(specFullDefinition, ICPPASTCompositeTypeSpecifier.class);
+		assertTrue(AttributeUtil.hasNodiscardAttribute(((ICPPASTCompositeTypeSpecifier) specFullDefinition)));
+
+		CPPVariable var1Base = bh.assertNonProblem("var1", 4);
+		CPPVariable var2Spec = bh.assertNonProblem("var2", 4);
+		CPPVariable var3Spec = bh.assertNonProblem("var3", 4);
+		assertFalse(((CPPClassInstance) var1Base.getType()).isNoDiscard());
+		assertTrue(((CPPClassInstance) var2Spec.getType()).isNoDiscard());
+		assertTrue(((CPPClassInstance) var3Spec.getType()).isNoDiscard());
+	}
 }

core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/pdom/tests/ClassTests.java

@@ -244,4 +244,14 @@ public class ClassTests extends PDOMTestBase {
 
 		assertTrue(classBinding.isFinal());
 	}
+
+	public void testNoDiscardClass() throws Exception {
+		char[][] name = { "F".toCharArray() };
+		IBinding[] bindings = pdom.findBindings(name, IndexFilter.ALL, npm());
+		assertEquals(1, bindings.length);
+		assertInstance(bindings[0], ICPPClassType.class);
+		ICPPClassType classBinding = (ICPPClassType) bindings[0];
+
+		assertTrue(classBinding.isNoDiscard());
+	}
 }

core/org.eclipse.cdt.core.tests/resources/pdomtests/classTests/class.cpp

@@ -35,3 +35,6 @@ class D {
 
 class E final : public A {
 };
+
+class [[nodiscard]] F : public A {
+};

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/cpp/ICPPClassType.java

@@ -137,4 +137,11 @@ public interface ICPPClassType extends ICompositeType, ICPPBinding {
 	 * @since 5.5
 	 */
 	public int getVisibility(IBinding member);
+
+	/**
+	 * Returns whether this type is declared 'nodiscard'.
+	 *
+	 * @since 6.12
+	 */
+	public boolean isNoDiscard();
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassSpecialization.java

@@ -46,6 +46,7 @@ import org.eclipse.cdt.core.dom.ast.cpp.ICPPTemplateDefinition;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPTemplateInstance;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPTemplateParameterMap;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPUsingDeclaration;
+import org.eclipse.cdt.core.parser.util.AttributeUtil;
 import org.eclipse.cdt.core.parser.util.CharArrayUtils;
 import org.eclipse.cdt.core.parser.util.ObjectMap;
 import org.eclipse.cdt.internal.core.dom.parser.IRecursionResolvingBinding;
@@ -510,6 +511,19 @@ public class CPPClassSpecialization extends CPPSpecialization
 		return false;
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		ICPPASTCompositeTypeSpecifier typeSpecifier = getCompositeTypeSpecifier();
+		if (typeSpecifier != null) {
+			return AttributeUtil.hasNodiscardAttribute(typeSpecifier);
+		}
+		ICPPClassType clazz = getSpecializedBinding();
+		if (clazz != null) {
+			return clazz.isNoDiscard();
+		}
+		return false;
+	}
+
 	@Override
 	public int getVisibility(IBinding member) {
 		return ClassTypeHelper.getVisibility(this, member);

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassTemplate.java

@@ -44,6 +44,7 @@ import org.eclipse.cdt.core.dom.ast.cpp.ICPPUsingDeclaration;
 import org.eclipse.cdt.core.index.IIndexBinding;
 import org.eclipse.cdt.core.index.IIndexFileSet;
 import org.eclipse.cdt.core.parser.util.ArrayUtil;
+import org.eclipse.cdt.core.parser.util.AttributeUtil;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.CPPTemplates;
 
 /**
@@ -266,6 +267,15 @@ public class CPPClassTemplate extends CPPTemplateDefinition
 		return false;
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		ICPPASTCompositeTypeSpecifier typeSpecifier = getCompositeTypeSpecifier();
+		if (typeSpecifier != null) {
+			return AttributeUtil.hasNodiscardAttribute(typeSpecifier);
+		}
+		return false;
+	}
+
 	@Override
 	public int getVisibility(IBinding member) {
 		return ClassTypeHelper.getVisibility(this, member);

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassType.java

@@ -44,6 +44,7 @@ import org.eclipse.cdt.core.dom.ast.cpp.ICPPUsingDeclaration;
 import org.eclipse.cdt.core.index.IIndex;
 import org.eclipse.cdt.core.index.IIndexBinding;
 import org.eclipse.cdt.core.parser.util.ArrayUtil;
+import org.eclipse.cdt.core.parser.util.AttributeUtil;
 import org.eclipse.cdt.internal.core.dom.Linkage;
 import org.eclipse.cdt.internal.core.dom.parser.ASTNode;
 import org.eclipse.cdt.internal.core.dom.parser.ProblemBinding;
@@ -142,6 +143,11 @@ public class CPPClassType extends PlatformObject implements ICPPInternalClassTyp
 		public int getVisibility(IBinding member) {
 			throw new IllegalArgumentException(member.getName() + " is not a member of " + getName()); //$NON-NLS-1$
 		}
+
+		@Override
+		public boolean isNoDiscard() {
+			return false;
+		}
 	}
 
 	private IASTName definition;
@@ -455,6 +461,15 @@ public class CPPClassType extends PlatformObject implements ICPPInternalClassTyp
 		return false;
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		ICPPASTCompositeTypeSpecifier typeSpecifier = getCompositeTypeSpecifier();
+		if (typeSpecifier != null) {
+			return AttributeUtil.hasNodiscardAttribute(typeSpecifier);
+		}
+		return false;
+	}
+
 	private IASTName stripQualifier(IASTName name) {
 		if (name instanceof ICPPASTQualifiedName) {
 			name = ((ICPPASTQualifiedName) name).getLastName();

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClosureType.java

@@ -592,4 +592,9 @@ public class CPPClosureType extends PlatformObject implements ICPPClassType, ICP
 			return CPPClosureType.this.getConstructors();
 		}
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		return false;
+	}
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPDeferredClassInstance.java

@@ -178,6 +178,11 @@ public class CPPDeferredClassInstance extends CPPUnknownBinding
 		return false;
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		return false;
+	}
+
 	@Override
 	public ICPPTemplateArgument[] getTemplateArguments() {
 		return fArguments;

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPTemplateTemplateParameter.java

@@ -259,6 +259,11 @@ public class CPPTemplateTemplateParameter extends CPPTemplateParameter
 		return false;
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		return false;
+	}
+
 	@Override
 	public int getVisibility(IBinding member) {
 		throw new IllegalArgumentException(member.getName() + " is not a member of " + getName()); //$NON-NLS-1$

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPTemplateTemplateParameterSpecialization.java

@@ -127,6 +127,11 @@ public class CPPTemplateTemplateParameterSpecialization extends CPPTemplateParam
 		return false;
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		return false;
+	}
+
 	@Override
 	public int getVisibility(IBinding member) {
 		return getSpecializedBinding().getVisibility(member);

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPUnknownMemberClass.java

@@ -139,6 +139,11 @@ public class CPPUnknownMemberClass extends CPPUnknownMember implements ICPPUnkno
 		return false;
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		return false;
+	}
+
 	@Override
 	public int getVisibility(IBinding member) {
 		throw new IllegalArgumentException(member.getName() + " is not a member of " + getName()); //$NON-NLS-1$

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/index/composite/cpp/CompositeCPPClassType.java

@@ -231,4 +231,9 @@ class CompositeCPPClassType extends CompositeCPPBinding implements ICPPClassType
 	public int getVisibility(IBinding member) {
 		return ((ICPPClassType) rbinding).getVisibility(member);
 	}
+
+	@Override
+	public boolean isNoDiscard() {
+		return ((ICPPClassType) rbinding).isNoDiscard();
+	}
 }

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/index/composite/cpp/CompositeCPPTemplateTemplateParameter.java

@@ -190,6 +190,11 @@ public class CompositeCPPTemplateTemplateParameter extends CompositeCPPBinding
 		return false;
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		return false;
+	}
+
 	@Override
 	public int getVisibility(IBinding member) {
 		throw new IllegalArgumentException(member.getName() + " is not a member of " + getName()); //$NON-NLS-1$

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/PDOM.java

@@ -305,10 +305,11 @@ public class PDOM extends PlatformObject implements IPDOM {
 	 *
 	 *  CDT 9.12 development (version not supported on the 9.11.x branch)
 	 *  216.0 - Added nodiscard function information, bug 534420
+	 *  217.0 - Added nodiscard class/struct information, bug 534420
 	 */
-	private static final int MIN_SUPPORTED_VERSION = version(216, 0);
+	private static final int MIN_SUPPORTED_VERSION = version(217, 0);
-	private static final int MAX_SUPPORTED_VERSION = version(216, Short.MAX_VALUE);
+	private static final int MAX_SUPPORTED_VERSION = version(217, Short.MAX_VALUE);
-	private static final int DEFAULT_VERSION = version(216, 0);
+	private static final int DEFAULT_VERSION = version(217, 0);
 
 	private static int version(int major, int minor) {
 		return (major << 16) + minor;

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/PDOMASTAdapter.java

@@ -669,6 +669,11 @@ public class PDOMASTAdapter {
 		public int getVisibility(IBinding member) {
 			return ((ICPPClassType) fDelegate).getVisibility(member);
 		}
+
+		@Override
+		public boolean isNoDiscard() {
+			return ((ICPPClassType) fDelegate).isNoDiscard();
+		}
 	}
 
 	private static class AnonymousClassSpecialization extends AnonymousClassType implements ICPPClassSpecialization {

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/cpp/PDOMCPPClassSpecialization.java

@@ -72,6 +72,7 @@ class PDOMCPPClassSpecialization extends PDOMCPPSpecialization
 
 	private static final byte FLAGS_FINAL = 0x01;
 	private static final byte FLAGS_HAS_OWN_SCOPE = 0x02;
+	private static final byte FLAGS_NODISCARD = 0x03;
 
 	private volatile ICPPClassScope fScope;
 	private ObjectMap specializationMap; // Obtained from the synchronized PDOM cache.
@@ -508,6 +509,16 @@ class PDOMCPPClassSpecialization extends PDOMCPPSpecialization
 		}
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		try {
+			return (getFlags() & FLAGS_NODISCARD) != 0;
+		} catch (CoreException e) {
+			CCorePlugin.log(e);
+			return false;
+		}
+	}
+
 	private boolean hasOwnScope() throws CoreException {
 		return (getFlags() & FLAGS_HAS_OWN_SCOPE) != 0;
 	}

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/cpp/PDOMCPPClassType.java

@@ -60,8 +60,9 @@ class PDOMCPPClassType extends PDOMCPPBinding implements IPDOMCPPClassType, IPDO
 	private static final int ANONYMOUS = KEY + 1; // byte
 	private static final int FINAL = ANONYMOUS + 1; // byte
 	private static final int VISIBLE_TO_ADL_ONLY = FINAL + 1; // byte
+	private static final int NO_DISCARD = VISIBLE_TO_ADL_ONLY + 1; // byte
 	@SuppressWarnings("hiding")
-	protected static final int RECORD_SIZE = VISIBLE_TO_ADL_ONLY + 1;
+	protected static final int RECORD_SIZE = NO_DISCARD + 1;
 
 	private PDOMCPPClassScope fScope; // No need for volatile, all fields of PDOMCPPClassScope are final.
 
@@ -73,6 +74,7 @@ class PDOMCPPClassType extends PDOMCPPBinding implements IPDOMCPPClassType, IPDO
 		setAnonymous(classType);
 		setFinal(classType);
 		setVisibleToAdlOnly(visibleToAdlOnly);
+		setNoDiscard(classType);
 		// Linked list is initialized by storage being zero'd by malloc.
 	}
 
@@ -97,6 +99,7 @@ class PDOMCPPClassType extends PDOMCPPBinding implements IPDOMCPPClassType, IPDO
 			setKind(ct);
 			setAnonymous(ct);
 			setFinal(ct);
+			setNoDiscard(ct);
 			super.update(linkage, newBinding);
 		}
 	}
@@ -113,6 +116,10 @@ class PDOMCPPClassType extends PDOMCPPBinding implements IPDOMCPPClassType, IPDO
 		getDB().putByte(record + FINAL, (byte) (ct.isFinal() ? 1 : 0));
 	}
 
+	private void setNoDiscard(ICPPClassType ct) throws CoreException {
+		getDB().putByte(record + NO_DISCARD, (byte) (ct.isNoDiscard() ? 1 : 0));
+	}
+
 	@Override
 	public void setVisibleToAdlOnly(boolean visibleToAdlOnly) throws CoreException {
 		getDB().putByte(record + VISIBLE_TO_ADL_ONLY, (byte) (visibleToAdlOnly ? 1 : 0));
@@ -279,6 +286,16 @@ class PDOMCPPClassType extends PDOMCPPBinding implements IPDOMCPPClassType, IPDO
 		}
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		try {
+			return getDB().getByte(record + NO_DISCARD) != 0;
+		} catch (CoreException e) {
+			CCorePlugin.log(e);
+			return false;
+		}
+	}
+
 	@Override
 	public boolean isVisibleToAdlOnly() {
 		try {

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/cpp/PDOMCPPTemplateTemplateParameter.java

@@ -349,6 +349,11 @@ public class PDOMCPPTemplateTemplateParameter extends PDOMCPPBinding implements
 		return false;
 	}
 
+	@Override
+	public boolean isNoDiscard() {
+		return false;
+	}
+
 	@Override
 	public ICPPTemplateParameter adaptTemplateParameter(ICPPTemplateParameter param) {
 		int pos = param.getParameterPosition();