From fe7a9d7856d36de76d8076a03743b1ce6731459c Mon Sep 17 00:00:00 2001
From: "Igor V. Kovalenko" <76685079+i-garrison@users.noreply.github.com>
Date: Sat, 28 Jan 2023 18:54:09 +0300
Subject: [PATCH] Do not allow structured binding initializer referencing
 introduced name (#241)

If name lookup ends up with a variable, additionally check if node being
resolved is part of the structured binding initializer introducing found
variable. If this is the case, produce problem binding and report structured
binding declaration error via codan.

This change also prevents infinite recursion trying to resolve auto type of
introduced variable while evaluating such problematic initializer.
---
 .../META-INF/MANIFEST.MF                       |  2 +-
 .../OSGI-INF/l10n/bundle.properties            |  3 +++
 .../org.eclipse.cdt.codan.checkers/plugin.xml  | 10 ++++++++++
 .../checkers/ProblemBindingChecker.java        | 18 ++++++++++++++++++
 .../ast2/cxx17/StructuredBindingTests.java     |  8 ++++++++
 .../cdt/core/dom/ast/IProblemBinding.java      |  2 ++
 .../cdt/core/dom/ast/ISemanticProblem.java     |  2 ++
 .../dom/parser/cpp/semantics/CPPSemantics.java | 15 +++++++++++++++
 .../internal/core/parser/ParserMessages.java   |  2 ++
 .../core/parser/ParserMessages.properties      |  1 +
 10 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/codan/org.eclipse.cdt.codan.checkers/META-INF/MANIFEST.MF b/codan/org.eclipse.cdt.codan.checkers/META-INF/MANIFEST.MF
index bf8136cff1b..5050959033c 100644
--- a/codan/org.eclipse.cdt.codan.checkers/META-INF/MANIFEST.MF
+++ b/codan/org.eclipse.cdt.codan.checkers/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %Bundle-Name
 Bundle-SymbolicName: org.eclipse.cdt.codan.checkers;singleton:=true
-Bundle-Version: 3.5.0.qualifier
+Bundle-Version: 3.5.100.qualifier
 Bundle-Activator: org.eclipse.cdt.codan.checkers.CodanCheckersActivator
 Require-Bundle: org.eclipse.core.runtime,
  org.eclipse.core.resources,
diff --git a/codan/org.eclipse.cdt.codan.checkers/OSGI-INF/l10n/bundle.properties b/codan/org.eclipse.cdt.codan.checkers/OSGI-INF/l10n/bundle.properties
index 7654d0e4098..15bbc5c8fe0 100644
--- a/codan/org.eclipse.cdt.codan.checkers/OSGI-INF/l10n/bundle.properties
+++ b/codan/org.eclipse.cdt.codan.checkers/OSGI-INF/l10n/bundle.properties
@@ -113,6 +113,9 @@ problem.name.11 = Method cannot be resolved
 problem.description.12 = Name resolution problem found by the indexer
 problem.messagePattern.12 = Field ''{0}'' could not be resolved
 problem.name.12 = Field cannot be resolved
+problem.description.13 = Name resolution problem found by the indexer
+problem.messagePattern.13 = Structured binding initializer expression refers to introduced name ''{0}''
+problem.name.13 = Invalid structured binding declaration
 checker.name.AbstractClassCreation = Abstract class cannot be instantiated
 problem.name.AbstractClassCreation = Abstract class cannot be instantiated
 problem.messagePattern.AbstractClassCreation = The type ''{0}'' must implement the inherited pure virtual method ''{1}''\u0020
diff --git a/codan/org.eclipse.cdt.codan.checkers/plugin.xml b/codan/org.eclipse.cdt.codan.checkers/plugin.xml
index 08c0b921af2..7a4d11c604f 100644
--- a/codan/org.eclipse.cdt.codan.checkers/plugin.xml
+++ b/codan/org.eclipse.cdt.codan.checkers/plugin.xml
@@ -273,6 +273,16 @@
                messagePattern="%problem.messagePattern.12"
                name="%problem.name.12">
          </problem>
+         <problem
+               category="org.eclipse.cdt.codan.core.categories.CompilerErrors"
+               defaultEnabled="true"
+               defaultSeverity="Error"
+               description="%problem.description.13"
+               id="org.eclipse.cdt.codan.internal.checkers.StructuredBindingDeclarationProblem"
+               markerType="org.eclipse.cdt.codan.core.codanSemanticProblem"
+               messagePattern="%problem.messagePattern.13"
+               name="%problem.name.13">
+         </problem>
       </checker>
       <checker
             class="org.eclipse.cdt.codan.internal.checkers.AssignmentToItselfChecker"
diff --git a/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/ProblemBindingChecker.java b/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/ProblemBindingChecker.java
index 878413a247a..0b279576579 100644
--- a/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/ProblemBindingChecker.java
+++ b/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/ProblemBindingChecker.java
@@ -40,6 +40,7 @@ import org.eclipse.cdt.core.dom.ast.IProblemBinding;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTDeclarator;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTLiteralExpression;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTQualifiedName;
+import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTStructuredBindingDeclaration;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTTemplateId;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPClassType;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPFunction;
@@ -64,6 +65,7 @@ public class ProblemBindingChecker extends AbstractIndexAstChecker {
 	public static String ERR_ID_FieldResolutionProblem = "org.eclipse.cdt.codan.internal.checkers.FieldResolutionProblem"; //$NON-NLS-1$
 	public static String ERR_ID_VariableResolutionProblem = "org.eclipse.cdt.codan.internal.checkers.VariableResolutionProblem"; //$NON-NLS-1$
 	public static String ERR_ID_Candidates = "org.eclipse.cdt.codan.internal.checkers.Candidates"; //$NON-NLS-1$
+	public static String ERR_ID_StructuredBindingDeclarationProblem = "org.eclipse.cdt.codan.internal.checkers.StructuredBindingDeclarationProblem"; //$NON-NLS-1$
 
 	@Override
 	public boolean runInEditor() {
@@ -126,6 +128,22 @@ public class ProblemBindingChecker extends AbstractIndexAstChecker {
 										contextFlagsString);
 								return PROCESS_CONTINUE;
 							}
+							if (id == IProblemBinding.SEMANTIC_INVALID_STRUCTURED_BINDING_INITIALIZER) {
+								IASTNode problemNode = parentNode;
+								while (problemNode != null) {
+									if (problemNode instanceof ICPPASTStructuredBindingDeclaration) {
+										break;
+									}
+									problemNode = problemNode.getParent();
+								}
+								if (problemNode == null) {
+									// this should not happen because problem binding should be inside structured binding initializer subtree
+									problemNode = parentNode;
+								}
+								reportProblem(ERR_ID_StructuredBindingDeclarationProblem, problemNode,
+										parentNode.getRawSignature(), contextFlagsString);
+								return PROCESS_CONTINUE;
+							}
 							if (id == IProblemBinding.SEMANTIC_INVALID_REDECLARATION) {
 								reportProblem(ERR_ID_RedeclarationProblem, name, name.getRawSignature(),
 										contextFlagsString);
diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/cxx17/StructuredBindingTests.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/cxx17/StructuredBindingTests.java
index 5bbaebd81fd..a2d9446969d 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/cxx17/StructuredBindingTests.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/cxx17/StructuredBindingTests.java
@@ -415,4 +415,12 @@ public class StructuredBindingTests extends AST2CPPTestBase {
 		assertEquals(IntegralValue.create(1), subvalues[0].getValue());
 		assertEquals(FloatingPointValue.create(2.0), subvalues[1].getValue());
 	}
+
+	//void f() {
+	//  auto& [x] = x.y;
+	//}
+	public void testInvalidReferenceToIntroducedName() throws Exception {
+		BindingAssertionHelper ba = getAssertionHelper();
+		ba.assertProblem("x.y;", 1);
+	}
 }
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/IProblemBinding.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/IProblemBinding.java
index a1a7bb73c55..7ec31006142 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/IProblemBinding.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/IProblemBinding.java
@@ -65,6 +65,8 @@ public interface IProblemBinding extends IBinding, IScope, IType, ISemanticProbl
 	public static final int SEMANTIC_RECURSION_IN_LOOKUP = BINDING_RECURSION_IN_LOOKUP;
 	/** @since 5.1 */
 	public static final int SEMANTIC_INVALID_TEMPLATE_ARGUMENTS = BINDING_INVALID_TEMPLATE_ARGUMENTS;
+	/** @since 8.1 */
+	public static final int SEMANTIC_INVALID_STRUCTURED_BINDING_INITIALIZER = BINDING_INVALID_STRUCTURED_BINDING_INITIALIZER;
 
 	/**
 	 * @deprecated There may be additional problems.
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/ISemanticProblem.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/ISemanticProblem.java
index 3134e58fad9..5c23def3eb8 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/ISemanticProblem.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/core/dom/ast/ISemanticProblem.java
@@ -37,6 +37,8 @@ public interface ISemanticProblem {
 	int BINDING_RECURSION_IN_LOOKUP = 14;
 	int BINDING_INVALID_TEMPLATE_ARGUMENTS = 15;
 	int BINDING_NO_CLASS = 16;
+	/** @since 8.1 */
+	int BINDING_INVALID_STRUCTURED_BINDING_INITIALIZER = 17;
 
 	int TYPE_NO_NAME = 10000;
 	int TYPE_UNRESOLVED_NAME = 10001;
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPSemantics.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPSemantics.java
index 45f8fb677b5..5d7c92b7cb5 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPSemantics.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPSemantics.java
@@ -409,6 +409,21 @@ public class CPPSemantics {
 			}
 		}
 
+		// If any name in the initializer refers to introduced names then declaration is ill-formed.
+		if (binding instanceof ICPPInternalBinding internalBinding && internalBinding.getDefinition() != null
+				&& internalBinding.getDefinition()
+						.getParent() instanceof ICPPASTStructuredBindingDeclaration declaration) {
+			IASTNode parent = lookupName.getParent();
+			while (parent != null) {
+				if (parent == declaration) {
+					binding = new ProblemBinding(lookupName, data.getLookupPoint(),
+							IProblemBinding.SEMANTIC_INVALID_STRUCTURED_BINDING_INITIALIZER, data.getFoundBindings());
+					break;
+				}
+				parent = parent.getParent();
+			}
+		}
+
 		if (binding instanceof IProblemBinding)
 			return binding;
 
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/ParserMessages.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/ParserMessages.java
index fc85d3662a6..385715c75b8 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/ParserMessages.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/ParserMessages.java
@@ -93,6 +93,8 @@ public class ParserMessages {
 			return "ISemanticProblem.BINDING_INVALID_REDECLARATION";
 		case ISemanticProblem.BINDING_INVALID_REDEFINITION:
 			return "ISemanticProblem.BINDING_INVALID_REDEFINITION";
+		case ISemanticProblem.BINDING_INVALID_STRUCTURED_BINDING_INITIALIZER:
+			return "ISemanticProblem.BINDING_INVALID_STRUCTURED_BINDING_INITIALIZER";
 		case ISemanticProblem.BINDING_INVALID_TEMPLATE_ARGUMENTS:
 			return "ISemanticProblem.BINDING_INVALID_TEMPLATE_ARGUMENTS";
 		case ISemanticProblem.BINDING_INVALID_TYPE:
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/ParserMessages.properties b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/ParserMessages.properties
index bc9e25aeab0..0e90775cd0b 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/ParserMessages.properties
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/ParserMessages.properties
@@ -71,6 +71,7 @@ ISemanticProblem.BINDING_INVALID_REDECLARATION=Invalid redeclaration of the name
 ISemanticProblem.BINDING_RECURSION_IN_LOOKUP=Recursion while looking up ''{0}''
 ISemanticProblem.BINDING_MEMBER_DECLARATION_NOT_FOUND=A declaration could not be found for this member definition: {0}
 ISemanticProblem.BINDING_INVALID_TEMPLATE_ARGUMENTS=A template id provides illegal arguments for the instantiation: {0}
+ISemanticProblem.BINDING_INVALID_STRUCTURED_BINDING_INITIALIZER=Invalid structured binding initializer referencing introduced name ''{0}''
 
 ISemanticProblem.TYPE_NO_NAME=Type specification lacks a name
 ISemanticProblem.TYPE_UNRESOLVED_NAME=Type depends on an unresolved name