Fix removal of this cleanup to avoid forward field refs in lambdas (#…

…1212)

- fixes #1211
- add check for a field reference in a lambda in a field initializer
  in which case, skip
- add new test to CleanUpTest1d8

org.eclipse.jdt.core.manipulation/core extension/org/eclipse/jdt/internal/corext/fix/CodeStyleFixCore.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2019, 2023 IBM Corporation and others.
+ * Copyright (c) 2019, 2024 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -31,16 +31,19 @@
 import org.eclipse.jdt.core.dom.AbstractTypeDeclaration;
 import org.eclipse.jdt.core.dom.Assignment;
 import org.eclipse.jdt.core.dom.Block;
+import org.eclipse.jdt.core.dom.BodyDeclaration;
 import org.eclipse.jdt.core.dom.ClassInstanceCreation;
 import org.eclipse.jdt.core.dom.CompilationUnit;
 import org.eclipse.jdt.core.dom.Expression;
 import org.eclipse.jdt.core.dom.ExpressionStatement;
 import org.eclipse.jdt.core.dom.FieldAccess;
+import org.eclipse.jdt.core.dom.FieldDeclaration;
 import org.eclipse.jdt.core.dom.IBinding;
 import org.eclipse.jdt.core.dom.IMethodBinding;
 import org.eclipse.jdt.core.dom.ITypeBinding;
 import org.eclipse.jdt.core.dom.IVariableBinding;
 import org.eclipse.jdt.core.dom.Initializer;
+import org.eclipse.jdt.core.dom.LambdaExpression;
 import org.eclipse.jdt.core.dom.MethodInvocation;
 import org.eclipse.jdt.core.dom.Modifier;
 import org.eclipse.jdt.core.dom.Name;
@@ -266,6 +269,12 @@ public boolean visit(final FieldAccess node) {
 			if (hasConflict(expression.getStartPosition(), name, ScopeAnalyzer.VARIABLES | ScopeAnalyzer.CHECK_VISIBILITY))
 				return true;
 
+			ASTNode ancestor= ASTNodes.getFirstAncestorOrNull(node, LambdaExpression.class, BodyDeclaration.class);
+			if (ancestor instanceof LambdaExpression lambdaAncestor) {
+				if (ASTNodes.getFirstAncestorOrNull(lambdaAncestor, FieldDeclaration.class) != null) {
+					return false;
+				}
+			}
 			Name qualifier= ((ThisExpression) expression).getQualifier();
 			if (qualifier != null) {
 				ITypeBinding outerClass= (ITypeBinding) qualifier.resolveBinding();

org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/quickfix/CleanUpTest1d8.java

@@ -6481,4 +6481,79 @@ public void testDoNotDoDeprecatedCleanup4() throws Exception { // https://github
 		assertRefactoringHasNoChange(new ICompilationUnit[] { cu1, cu2 });
 	}
 
+	@Test
+	public void testRemoveThisIssue1211() throws Exception { // https://github.com/eclipse-jdt/eclipse.jdt.ui/issues/1211
+		IPackageFragment pack1= fSourceFolder.createPackageFragment("test1", false, null);
+
+		String sample= "" //
+				+ "package test1;\n" //
+				+ "\n" //
+				+ "public class A {\n" //
+				+ "    public interface PropertyChangeListener {\n" //
+				+ "        void propertyChange(Object evt);\n" //
+				+ "\n" //
+				+ "    }\n" //
+				+ "\n" //
+				+ "    private final PropertyChangeListener listener = evt -> {\n" //
+				+ "        this.clientCache.get();\n" //
+				+ "    };\n" //
+				+ "\n" //
+				+ "    public void x() {\n" //
+				+ "        PropertyChangeListener listener = evt -> {\n" //
+				+ "            this.clientCache.get();\n" //
+				+ "        };\n" //
+				+ "        listener.propertyChange(listener);\n" //
+				+ "    }\n" //
+				+ "    interface Cache<V> {\n" //
+				+ "        V get();\n" //
+				+ "    }\n" //
+				+ "\n" //
+				+ "    final Cache<String> clientCache = new Cache<>() {\n" //
+				+ "        @Override\n" //
+				+ "        public String get() {\n" //
+				+ "            listener.propertyChange(null);\n" //
+				+ "            return \"\";\n" //
+				+ "        }\n" //
+				+ "    };\n" //
+				+ "}\n";
+		ICompilationUnit cu1= pack1.createCompilationUnit("A.java", sample, false, null);
+
+		enable(CleanUpConstants.MEMBER_ACCESSES_NON_STATIC_FIELD_USE_THIS);
+		enable(CleanUpConstants.MEMBER_ACCESSES_NON_STATIC_FIELD_USE_THIS_IF_NECESSARY);
+
+		sample= "" //
+				+ "package test1;\n" //
+				+ "\n" //
+				+ "public class A {\n" //
+				+ "    public interface PropertyChangeListener {\n" //
+				+ "        void propertyChange(Object evt);\n" //
+				+ "\n" //
+				+ "    }\n" //
+				+ "\n" //
+				+ "    private final PropertyChangeListener listener = evt -> {\n" //
+				+ "        this.clientCache.get();\n" //
+				+ "    };\n" //
+				+ "\n" //
+				+ "    public void x() {\n" //
+				+ "        PropertyChangeListener listener = evt -> {\n" //
+				+ "            clientCache.get();\n" //
+				+ "        };\n" //
+				+ "        listener.propertyChange(listener);\n" //
+				+ "    }\n" //
+				+ "    interface Cache<V> {\n" //
+				+ "        V get();\n" //
+				+ "    }\n" //
+				+ "\n" //
+				+ "    final Cache<String> clientCache = new Cache<>() {\n" //
+				+ "        @Override\n" //
+				+ "        public String get() {\n" //
+				+ "            listener.propertyChange(null);\n" //
+				+ "            return \"\";\n" //
+				+ "        }\n" //
+				+ "    };\n" //
+				+ "}\n";
+		String expected1= sample;
+		assertRefactoringResultAsExpected(new ICompilationUnit[] { cu1 }, new String[] { expected1 }, null);
+    }
+
 }