Redundant toString() in string template: highlight selector only

And not the receiver. So #KT-18253 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/RemoveToStringInStringTemplateInspection.kt

@@ -19,7 +19,6 @@ package org.jetbrains.kotlin.idea.inspections
 import com.intellij.codeInsight.FileModificationService
 import com.intellij.codeInspection.*
 import com.intellij.openapi.project.Project
-import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
 import org.jetbrains.kotlin.idea.core.getDeepestSuperDeclarations
 import org.jetbrains.kotlin.idea.intentions.toResolvedCall
@@ -31,13 +30,15 @@ import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 class RemoveToStringInStringTemplateInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession) =
             object : KtVisitorVoid() {
-                override fun visitCallExpression(expression: KtCallExpression) {
-                    val qualifiedExpression = expression.parent as? KtDotQualifiedExpression ?: return
-                    if (qualifiedExpression.parent !is KtBlockStringTemplateEntry) return
-                    if (qualifiedExpression.receiverExpression is KtSuperExpression) return
-                    if (!qualifiedExpression.isToString()) return
+                override fun visitDotQualifiedExpression(expression: KtDotQualifiedExpression) {
+                    super.visitDotQualifiedExpression(expression)
 
-                    holder.registerProblem(expression,
+                    if (expression.parent !is KtBlockStringTemplateEntry) return
+                    if (expression.receiverExpression is KtSuperExpression) return
+                    val selectorExpression = expression.selectorExpression ?: return
+                    if (!expression.isToString()) return
+
+                    holder.registerProblem(selectorExpression,
                                            "Redundant 'toString()' call in string template",
                                            ProblemHighlightType.LIKE_UNUSED_SYMBOL,
                                            RemoveToStringFix())

idea/testData/inspectionsLocal/removeToStringInStringTemplate/.inspection

@@ -0,0 +1 @@
+org.jetbrains.kotlin.idea.inspections.RemoveToStringInStringTemplateInspection

idea/testData/inspectionsLocal/removeToStringInStringTemplate/caretInReceiver.kt

@@ -0,0 +1,7 @@
+// PROBLEM: none
+
+fun foo(a: Int, b: Int) = a + b
+
+fun test(): String {
+    return "Foo: ${<caret>foo(0, 4).toString()}"
+}

idea/testData/inspectionsLocal/removeToStringInStringTemplate/caretInSelector.kt

@@ -0,0 +1,5 @@
+fun foo(a: Int, b: Int) = a + b
+
+fun test(): String {
+    return "Foo: ${foo(0, 4).<caret>toString()}"
+}

idea/testData/inspectionsLocal/removeToStringInStringTemplate/caretInSelector.kt.after

@@ -0,0 +1,5 @@
+fun foo(a: Int, b: Int) = a + b
+
+fun test(): String {
+    return "Foo: ${foo(0, 4)}"
+}

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

@@ -147,6 +147,27 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
         }
     }
 
+    @TestMetadata("idea/testData/inspectionsLocal/removeToStringInStringTemplate")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class RemoveToStringInStringTemplate extends AbstractLocalInspectionTest {
+        public void testAllFilesPresentInRemoveToStringInStringTemplate() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/inspectionsLocal/removeToStringInStringTemplate"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), TargetBackend.ANY, true);
+        }
+
+        @TestMetadata("caretInReceiver.kt")
+        public void testCaretInReceiver() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/removeToStringInStringTemplate/caretInReceiver.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("caretInSelector.kt")
+        public void testCaretInSelector() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/removeToStringInStringTemplate/caretInSelector.kt");
+            doTest(fileName);
+        }
+    }
+
     @TestMetadata("idea/testData/inspectionsLocal/replaceArrayOfWithLiteral")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)