Fix extract method refactoring to recognize a member class collision (#1761)

- modify ExtractMethodRefactoring.checkForMethodOverride() to also
  check for a member class
- add new test to ExtractMethodTests
- fixes #1758

Author: jjohnstn

org.eclipse.jdt.core.manipulation/refactoring/org/eclipse/jdt/internal/corext/refactoring/code/ExtractMethodRefactoring.java

@@ -564,7 +564,7 @@ protected RefactoringStatus checkForMethodOverride() {
 			if (obj instanceof IType resultType) {
 				try {
 					ASTNode typeDecl= null;
-					if (resultType.isLocal() || resultType.isAnonymous()) {
+					if (resultType.isLocal() || resultType.isAnonymous() || resultType.isMember()) {
 						ICompilationUnit icu= resultType.getCompilationUnit();
 						typeDecl= getTypeDeclaration(resultType, icu);
 					}

org.eclipse.jdt.ui.tests.refactoring/resources/ExtractMethodWorkSpace/ExtractMethodTests/invalidSelection/A_testIssue1758.java

@@ -0,0 +1,18 @@
+package invalidSelection;
+
+public class A_testIssue1758 {
+	public void foo() {
+		/*]*/int i;/*[*/
+	}
+}
+
+class SubClass {
+	void extracted() {
+	}
+
+	class InnerClass extends A_testIssue1758 {
+		void testMethod() {
+			extracted();
+		}
+	}
+}

org.eclipse.jdt.ui.tests.refactoring/test cases/org/eclipse/jdt/ui/tests/refactoring/ExtractMethodTests.java

@@ -2735,4 +2735,9 @@ public void testIssue1357_2() throws Exception {
 	public void testIssue1516() throws Exception {
 		invalidSelectionTest();
 	}
+
+	@Test
+	public void testIssue1758() throws Exception {
+		invalidSelectionTest();
+	}
 }