172: Revert "Data Inflow: Support grouping by leaf expressions"

This reverts commit d5af2db2f259c7d55d38be73b9a5136e3aefd580.

idea/src/org/jetbrains/kotlin/idea/slicer/KotlinSliceProvider.kt.172

@@ -28,11 +28,6 @@ import org.jetbrains.kotlin.psi.psiUtil.parentsWithSelf
 class KotlinSliceProvider : SliceLanguageSupportProvider {
     override fun createRootUsage(element: PsiElement, params: SliceAnalysisParams) = KotlinSliceUsage(element, params)
 
-    override fun transform(usage: SliceUsage): Collection<SliceUsage>? {
-        if (usage is KotlinSliceUsage) return null
-        return listOf(KotlinSliceUsage(usage.element, usage.parent, 0, false))
-    }
-
     override fun getExpressionAtCaret(atCaret: PsiElement?, dataFlowToThis: Boolean): KtExpression? {
         val element =
                 atCaret?.parentsWithSelf

idea/src/org/jetbrains/kotlin/idea/slicer/KotlinSliceUsage.kt.172

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.idea.slicer
+
+import com.intellij.psi.PsiElement
+import com.intellij.slicer.SliceAnalysisParams
+import com.intellij.slicer.SliceUsage
+import com.intellij.util.Processor
+import org.jetbrains.kotlin.psi.KtExpression
+
+open class KotlinSliceUsage : SliceUsage {
+    val lambdaLevel: Int
+    val forcedExpressionMode: Boolean
+
+    constructor(element: PsiElement, parent: SliceUsage, lambdaLevel: Int, forcedExpressionMode: Boolean) : super(element, parent) {
+        this.lambdaLevel = lambdaLevel
+        this.forcedExpressionMode = forcedExpressionMode
+    }
+
+    constructor(element: PsiElement, params: SliceAnalysisParams) : super(element, params) {
+        this.lambdaLevel = 0
+        this.forcedExpressionMode = false
+    }
+
+    override fun copy(): KotlinSliceUsage {
+        val element = usageInfo.element!!
+        if (parent == null) return KotlinSliceUsage(element, params)
+        return KotlinSliceUsage(element, parent, lambdaLevel, forcedExpressionMode)
+    }
+
+    public override fun processUsagesFlownDownTo(element: PsiElement, uniqueProcessor: Processor<SliceUsage>) {
+        InflowSlicer(element as? KtExpression ?: return, uniqueProcessor, this).processChildren()
+    }
+
+    public override fun processUsagesFlownFromThe(element: PsiElement, uniqueProcessor: Processor<SliceUsage>) {
+        OutflowSlicer(element as? KtExpression ?: return, uniqueProcessor, this).processChildren()
+    }
+}