CollapseIntoLoopAction: avoid counting loop for two iterations when step is not +1/-1

GitOrigin-RevId: d8aef85c6d2620a9dd7e9216932388672a049979

java/java-impl/src/com/intellij/codeInsight/intention/impl/CollapseIntoLoopAction.java

@@ -136,6 +136,8 @@ public class CollapseIntoLoopAction implements IntentionAction {
         last = cur;
       }
       if (start == null || step == null) return null;
+      // Prefer for(int x : new int[] {12, 17}) over for(int x = 12; x <= 17; x+= 5)  
+      if (myLoopElements.size() == 2 && step != 1L && step != -1L) return null;
       String suffix = PsiType.LONG.equals(myType) ? "L" : "";
       String initial = myType.getCanonicalText() + " " + varName + "=" + start + suffix;
       String condition =

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/collapseIntoLoop/afterThreeIterations.java

@@ -0,0 +1,8 @@
+// "Collapse into loop" "true"
+class X {
+  void test() {
+      for (int i = 12; i <= 22; i += 5) {
+          System.out.println(i);
+      }
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/collapseIntoLoop/afterTwoIterations.java

@@ -0,0 +1,8 @@
+// "Collapse into loop" "true"
+class X {
+  void test() {
+      for (int i : new int[]{12, 17}) {
+          System.out.println(i);
+      }
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/collapseIntoLoop/beforeThreeIterations.java

@@ -0,0 +1,8 @@
+// "Collapse into loop" "true"
+class X {
+  void test() {
+    <caret>System.out.println(12);
+    System.out.println(17);
+    System.out.println(22);
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/collapseIntoLoop/beforeTwoIterations.java

@@ -0,0 +1,7 @@
+// "Collapse into loop" "true"
+class X {
+  void test() {
+    <caret>System.out.println(12);
+    System.out.println(17);
+  }
+}