java: while -> foreach with empty loop (IDEA-268952)

GitOrigin-RevId: a569bb1c7046b97af445919e56abd5d2a46807cc

plugins/InspectionGadgets/src/com/siyeh/ig/migration/ForCanBeForeachInspection.java

@@ -490,7 +490,9 @@ public class ForCanBeForeachInspection extends BaseInspection {
                                   PsiVariable iterator, PsiType contentType, PsiElement childToSkip,
                                   CommentTracker commentTracker, StringBuilder out) {
     if (isIteratorNext(element, iterator, contentType)) {
-      out.append(contentVariableName);
+      if (!(element.getParent() instanceof PsiExpressionStatement)) {
+        out.append(contentVariableName);
+      }
     }
     else {
       final PsiElement[] children = element.getChildren();

plugins/InspectionGadgets/test/com/siyeh/igfixes/migration/while_can_be_foreach/EmptyLoop.after.java

@@ -0,0 +1,7 @@
+import java.util.Iterator;
+
+class MyTest {
+  public static void foo(Iterable<?> bar) {
+      for (Object o : bar) ;
+  }
+}

plugins/InspectionGadgets/test/com/siyeh/igfixes/migration/while_can_be_foreach/EmptyLoop.java

@@ -0,0 +1,8 @@
+import java.util.Iterator;
+
+class MyTest {
+  public static void foo(Iterable<?> bar) {
+    Iterator<?> it = bar.iterator();
+    wh<caret>ile (it.hasNext()) it.next();
+  }
+}

plugins/InspectionGadgets/testsrc/com/siyeh/ig/fixes/migration/WhileCanBeForeachFixTest.java

@@ -24,6 +24,7 @@ public class WhileCanBeForeachFixTest extends IGQuickFixesTestCase {
   public void testRawIterator() { doTest(); }
   public void testUnboxing() { doTest(); }
   public void testParentheses() { doTest(); }
+  public void testEmptyLoop() { doTest(); }
 
   @Override
   protected void tuneFixture(JavaModuleFixtureBuilder builder) {