JavaSliceBuilder: avoid decrementing beyond zero

Fixes EA-232342 - assert: JavaSliceBuilder.<init>

GitOrigin-RevId: 3f33f778c90199e8b7745d2ac29022d2d4716b06

java/java-impl/src/com/intellij/slicer/JavaSliceBuilder.java

@@ -89,14 +89,16 @@ final class JavaSliceBuilder {
    */
   @Contract(pure = true)
   @NotNull JavaSliceBuilder updateNesting(@NotNull Flow anno) {
-    JavaSliceBuilder result = this;
+    if (anno.targetIsContainer() && anno.sourceIsContainer()) {
+      return new JavaSliceBuilder(myParent, mySubstitutor, myIndexNesting, mySyntheticField, myFilter.unwrap().wrap());
+    }
     if (anno.targetIsContainer()) {
-      result = result.decrementNesting();
+      return decrementNesting();
     }
     if (anno.sourceIsContainer()) {
-      result = result.incrementNesting();
+      return incrementNesting();
     }
-    return result;
+    return this;
   }
 
   @Contract(pure = true)

java/java-tests/testData/codeInsight/slice/backward/BackAndForward.java

@@ -0,0 +1,8 @@
+import java.util.List;
+
+class Test {
+  void test(List<String> <flown11>list) {
+    String[] array = <flown1>list.toArray(new String[0]);
+    System.out.println(<caret>array);
+  }
+}

java/java-tests/testSrc/com/intellij/java/slicer/SliceBackwardTest.java

@@ -103,6 +103,7 @@ public class SliceBackwardTest extends SliceTestCase {
   public void testSearchOverriddenMethodsInThisClassHierarchyParamDfa() throws Exception { doTest();}
   public void testAppend() throws Exception { doTest();}
   public void testRequireNonNull() throws Exception { doTest();}
+  public void testBackAndForward() throws Exception { doTest();}
   
   public void testFilterIntRange() throws Exception { doTest(">=0");}
   public void testFilterIntRangeArray() throws Exception { doTest(">=0");}