From c026aafd84e454f77030132b7095b3971bd5a493 Mon Sep 17 00:00:00 2001
From: Snjezana Peco <snjezana.peco@redhat.com>
Date: Mon, 2 Mar 2020 23:14:24 +0100
Subject: [PATCH] Allow renaming lambda parameters

Signed-off-by: Snjezana Peco <snjezana.peco@redhat.com>
---
 .../handlers/PrepareRenameHandler.java        | 10 ++++++--
 .../handlers/PrepareRenameHandlerTest.java    | 23 +++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/PrepareRenameHandler.java b/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/PrepareRenameHandler.java
index 40b8ba48f3..0e1b811d6b 100644
--- a/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/PrepareRenameHandler.java
+++ b/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/PrepareRenameHandler.java
@@ -26,6 +26,7 @@
 import org.eclipse.jdt.internal.core.manipulation.search.OccurrencesFinder;
 import org.eclipse.jdt.ls.core.internal.JDTUtils;
 import org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin;
+import org.eclipse.jdt.ls.core.internal.corext.refactoring.RefactoringAvailabilityTester;
 import org.eclipse.jdt.ls.core.internal.corrections.InnovationContext;
 import org.eclipse.lsp4j.PrepareRenameResult;
 import org.eclipse.lsp4j.Range;
@@ -80,8 +81,13 @@ private boolean isBinaryOrPackage(ASTNode node) {
 		if (node instanceof Name) {
 			IBinding resolvedBinding = ((Name) node).resolveBinding();
 			IJavaElement element = resolvedBinding != null ? resolvedBinding.getJavaElement() : null;
-			if (element != null) {
-				return element.getAncestor(IJavaElement.CLASS_FILE) != null || element.getElementType() == IJavaElement.PACKAGE_FRAGMENT;
+			try {
+				if (element == null || element.getElementType() == IJavaElement.PACKAGE_FRAGMENT || !RefactoringAvailabilityTester.isRenameElementAvailable(element)) {
+					return true;
+				}
+			} catch (CoreException e) {
+				JavaLanguageServerPlugin.logException(e.getMessage(), e);
+				return true;
 			}
 		}
 		return false;
diff --git a/org.eclipse.jdt.ls.tests/src/org/eclipse/jdt/ls/core/internal/handlers/PrepareRenameHandlerTest.java b/org.eclipse.jdt.ls.tests/src/org/eclipse/jdt/ls/core/internal/handlers/PrepareRenameHandlerTest.java
index 0f88023616..529fc648a9 100644
--- a/org.eclipse.jdt.ls.tests/src/org/eclipse/jdt/ls/core/internal/handlers/PrepareRenameHandlerTest.java
+++ b/org.eclipse.jdt.ls.tests/src/org/eclipse/jdt/ls/core/internal/handlers/PrepareRenameHandlerTest.java
@@ -226,6 +226,29 @@ public void testRenameTypeParameterInMethod() throws JavaModelException, BadLoca
 		assertTrue(result.getLeft().getStart().getLine() > 0);
 	}
 
+	@Test
+	public void testRenameLambdaParameter() throws JavaModelException, BadLocationException {
+		IPackageFragment pack1 = sourceFolder.createPackageFragment("test1", false, null);
+
+		// @formatter:off
+		String[] codes =
+			{
+				"package test1;\n",
+				"import java.util.function.Function;\n",
+				"public class Test {\n",
+				"    Function<Integer, String> f = i|* -> \"\" + i;\n",
+				"}\n"
+			};
+		// @formatter:on
+		StringBuilder builder = new StringBuilder();
+		Position pos = mergeCode(builder, codes);
+		ICompilationUnit cu = pack1.createCompilationUnit("Test.java", builder.toString(), false, null);
+
+		Either<Range, PrepareRenameResult> result = prepareRename(cu, pos, "j");
+		assertNotNull(result.getLeft());
+		assertTrue(result.getLeft().getStart().getLine() > 0);
+	}
+
 	@Test
 	public void testRenameJavadoc() throws JavaModelException, BadLocationException {
 		IPackageFragment pack1 = sourceFolder.createPackageFragment("test1", false, null);