bug fix : duplicate local variable declaration

src/main/java/jd/core/process/analyzer/instruction/fast/FastInstructionListBuilder.java

@@ -251,6 +251,11 @@ private static List<List<Instruction>> getBlocks(Instruction instruction) {
             FastTest2Lists fastTest2Lists = (FastTest2Lists) instruction;
             return Arrays.asList(fastTest2Lists.getInstructions(), fastTest2Lists.getInstructions2());
         }
+        // /!\ order matters since FastTest2Lists extends FastTestList
+        if (instruction instanceof FastTestList) { // to convert to jdk16 pattern matching only when spotbugs #1617 and eclipse #577987 are solved
+            FastTestList fastTestList = (FastTestList) instruction;
+            return Collections.singletonList(fastTestList.getInstructions());
+        }
         if (instruction instanceof FastTry) { // to convert to jdk16 pattern matching only when spotbugs #1617 and eclipse #577987 are solved
             FastTry fastTry = (FastTry) instruction;
             List<List<Instruction>> instructions = new ArrayList<>();

src/test/java/jd/core/test/NumberUtilsTest.java

@@ -0,0 +1,19 @@
+package jd.core.test;
+
+import org.apache.commons.io.IOUtils;
+import org.junit.Test;
+
+import java.nio.charset.StandardCharsets;
+
+import static org.junit.Assert.assertEquals;
+
+/*
+ * Test for duplicate local variable bug fix.
+ */
+public class NumberUtilsTest extends AbstractTestCase {
+    @Test
+    public void test() throws Exception {
+        String output = decompile("org/apache/commons/lang3/math/NumberUtils");
+        assertEquals(IOUtils.toString(getClass().getResource("NumberUtils.txt"), StandardCharsets.UTF_8), output);
+    }
+}