Data Outflow: Allow for-loop variables

#KT-19018 Fixed

idea/src/org/jetbrains/kotlin/idea/slicer/Slicer.kt

@@ -113,9 +113,7 @@ private fun KtDeclaration.processVariableAccesses(
     )
 }
 
-private fun KtParameter.canProcess(): Boolean {
+private fun KtParameter.canProcess() = !isVarArg
-    return !(isLoopParameter || isVarArg)
-}
 
 abstract class Slicer(
         protected val element: KtExpression,

idea/testData/slicer/outflow/forVariable.kt

@@ -0,0 +1,9 @@
+// FLOW: OUT
+
+fun f1(param: String) {}
+
+fun f4(list: List<String>) {
+    for (<caret>s in list)
+        if (s.isNotEmpty())
+            f1(s)
+}

idea/testData/slicer/outflow/forVariable.results.txt

@@ -0,0 +1,4 @@
+6 for (<bold>s</bold> in list)
+7 	if (<bold>s</bold>.isNotEmpty())
+8 	f1(<bold>s</bold>)
+3 		fun f1(<bold>param: String</bold>) {}

idea/tests/org/jetbrains/kotlin/idea/slicer/SlicerTestGenerated.java

@@ -378,6 +378,12 @@ public class SlicerTestGenerated extends AbstractSlicerTest {
         doTest(fileName);
     }
 
+    @TestMetadata("outflow/forVariable.kt")
+    public void testOutflow_ForVariable() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/slicer/outflow/forVariable.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("outflow/funBodyExpression.kt")
     public void testOutflow_FunBodyExpression() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/slicer/outflow/funBodyExpression.kt");