Call chain --> Sequence: don't report if first call is 'groupingBy'

#KT-27104 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/collections/ConvertCallChainIntoSequenceInspection.kt

@@ -173,6 +173,7 @@ private fun KtQualifiedExpression.collectCallExpression(context: BindingContext)
         .dropWhile { !it.isTransformationOrTermination(context) }
         .takeWhile { it.isTransformationOrTermination(context) && !it.hasReturn() }
         .toList()
+        .dropLastWhile { it.calleeExpression?.text == "groupingBy" }
     if (transformationCalls.size < 2) return emptyList()
 
     return transformationCalls

idea/testData/inspectionsLocal/collections/convertCallChainIntoSequence/endsWithGroupingBy.kt

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+fun test(list: List<Int>) {
+    list.<caret>map { it * 2 }.map { it * 3 }.map { it * 4 }.groupingBy { it }
+}

idea/testData/inspectionsLocal/collections/convertCallChainIntoSequence/endsWithGroupingBy.kt.after

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+fun test(list: List<Int>) {
+    list.asSequence().map { it * 2 }.map { it * 3 }.map { it * 4 }.groupingBy { it }
+}

idea/testData/inspectionsLocal/collections/convertCallChainIntoSequence/startsWithGroupingBy.kt

@@ -0,0 +1,6 @@
+// PROBLEM: none
+// WITH_RUNTIME
+
+fun test(list: List<Int>) {
+    list.<caret>groupingBy { it }.reduce { _, acc, _ -> acc }
+}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -564,6 +564,11 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
                 runTest("idea/testData/inspectionsLocal/collections/convertCallChainIntoSequence/comment2.kt");
             }
 
+            @TestMetadata("endsWithGroupingBy.kt")
+            public void testEndsWithGroupingBy() throws Exception {
+                runTest("idea/testData/inspectionsLocal/collections/convertCallChainIntoSequence/endsWithGroupingBy.kt");
+            }
+
             @TestMetadata("mutableList.kt")
             public void testMutableList() throws Exception {
                 runTest("idea/testData/inspectionsLocal/collections/convertCallChainIntoSequence/mutableList.kt");
@@ -644,6 +649,11 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
                 runTest("idea/testData/inspectionsLocal/collections/convertCallChainIntoSequence/simple4.kt");
             }
 
+            @TestMetadata("startsWithGroupingBy.kt")
+            public void testStartsWithGroupingBy() throws Exception {
+                runTest("idea/testData/inspectionsLocal/collections/convertCallChainIntoSequence/startsWithGroupingBy.kt");
+            }
+
             @TestMetadata("idea/testData/inspectionsLocal/collections/convertCallChainIntoSequence/termination")
             @TestDataPath("$PROJECT_ROOT")
             @RunWith(JUnit3RunnerWithInners.class)