Prevent renaming of unnamed variables.

PiperOrigin-RevId: 827646320

Author: rluble

translator/src/main/java/com/google/devtools/j2objc/translate/VariableRenamer.java

@@ -303,7 +303,8 @@ public boolean visit(VariableDeclarationFragment variableDeclaration) {
   }
 
   private void handleVariable(VariableElement variable) {
-    if (variable.getKind().isField()) {
+    if (variable.getKind().isField() || ElementUtil.isUnnamed(variable)) {
+      // Do not rename fields or unnamed variables.
       return;
     }
     Scope scope = scopes.peek();

translator/src/test/java/com/google/devtools/j2objc/gen/StatementGeneratorTest.java

@@ -2174,14 +2174,18 @@ public void testUnnamedVariableDeclaration() throws IOException {
                       "  }",
                       "  void test() {",
                       "    Date _ = getCurrentDate();",
+                      "    Number _ = null;",
                       "    System.out.println(\"field initialized: \" + (currentDate != null));",
                       "  }",
                       "}"),
                   "Test",
                   "Test.m");
-          // Verify that the local variable is named "_", as javac uses an empty strings.
-          assertTranslation(
-              translation, "JavaUtilDate *_ = JreRetainedLocalValue([self getCurrentDate]);");
+          // Verify that unnamed local variable are named "_", as javac uses an empty strings. Also
+          // verify that if there are multiple unnamed variables, they are not renamed.
+          assertTranslatedLines(
+              translation,
+              "JavaUtilDate *_ = JreRetainedLocalValue([self getCurrentDate]);",
+              "NSNumber *_ = nil;");
         });
   }