Add restrictions for "simplifiable call chain" inspection

Do not use on maps; do not suggest for lambdas with return inside
Related to KT-18274

core/descriptors/src/org/jetbrains/kotlin/builtins/KotlinBuiltIns.java

@@ -615,6 +615,11 @@ public abstract class KotlinBuiltIns {
         return getBuiltInClassByName("String");
     }
 
+    @NotNull
+    public ClassDescriptor getCharSequence() {
+        return getBuiltInClassByName("CharSequence");
+    }
+
     @NotNull
     public ClassDescriptor getComparable() {
         return getBuiltInClassByName("Comparable");

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

@@ -19,7 +19,6 @@ package org.jetbrains.kotlin.idea.inspections.collections
 import com.intellij.codeInspection.ProblemHighlightType
 import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.openapi.util.TextRange
-import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.inspections.AbstractKotlinInspection
 import org.jetbrains.kotlin.psi.*
@@ -29,6 +28,8 @@ import org.jetbrains.kotlin.psi.psiUtil.startOffset
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.resolve.calls.model.DefaultValueArgument
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameOrNull
+import org.jetbrains.kotlin.types.typeUtil.builtIns
+import org.jetbrains.kotlin.types.typeUtil.isSubtypeOf
 
 class SimplifiableCallChainInspection : AbstractKotlinInspection() {
 
@@ -46,11 +47,19 @@ class SimplifiableCallChainInspection : AbstractKotlinInspection() {
                             firstCallExpression.calleeExpression?.text to secondCallExpression.calleeExpression?.text
                             ] ?: return
 
-                    val context = expression.analyze(BodyResolveMode.PARTIAL)
+                    val context = expression.analyze()
                     val firstResolvedCall = firstQualifiedExpression.getResolvedCall(context) ?: return
                     val conversion = actualConversions.firstOrNull {
                         firstResolvedCall.resultingDescriptor.fqNameOrNull()?.asString() == it.firstFqName
                     } ?: return
+                    // Do not apply on maps due to lack of relevant stdlib functions
+                    val firstReceiverType = firstResolvedCall.extensionReceiver?.type ?: return
+                    val builtIns = firstReceiverType.builtIns
+                    val mapType = builtIns.map.defaultType
+                    if (firstReceiverType.isSubtypeOf(mapType)) return
+                    // Do not apply for lambdas with return inside
+                    val lambdaArgument = firstCallExpression.lambdaArguments.firstOrNull()
+                    if (lambdaArgument?.anyDescendantOfType<KtReturnExpression>() == true) return
 
                     val secondResolvedCall = expression.getResolvedCall(context) ?: return
                     val secondResultingDescriptor = secondResolvedCall.resultingDescriptor
@@ -62,7 +71,9 @@ class SimplifiableCallChainInspection : AbstractKotlinInspection() {
 
                     if (conversion.replacement.startsWith("joinTo")) {
                         // Function parameter in map must have String result type
-                        if (!firstResolvedCall.hasLastFunctionalParameterWithResult(context) { KotlinBuiltIns.isString(it) }) return
+                        if (!firstResolvedCall.hasLastFunctionalParameterWithResult(context) {
+                            it.isSubtypeOf(builtIns.charSequence.defaultType)
+                        }) return
                     }
 
                     val descriptor = holder.manager.createProblemDescriptor(

idea/testData/inspectionsLocal/collections/simplifiableCallChain/joinToForHashMap.kt

@@ -0,0 +1,4 @@
+// PROBLEM: none
+// WITH_RUNTIME
+
+val x = hashMapOf(1 to 2, 3 to 4).<caret>map { (key, value) -> key + value }.joinToString()

idea/testData/inspectionsLocal/collections/simplifiableCallChain/joinToForMap.kt

@@ -0,0 +1,4 @@
+// PROBLEM: none
+// WITH_RUNTIME
+
+val x = mapOf(1 to 2, 3 to 4).<caret>map { (key, value) -> key + value }.joinToString()

idea/testData/inspectionsLocal/collections/simplifiableCallChain/joinToStringViaBuilder.kt

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+
+val x = listOf(1, 2, 3).<caret>map {
+    val sb = StringBuilder()
+    sb.append(it).append(" + ").append(it)
+    sb
+}.joinToString(prefix = "= ", separator = " + ")

idea/testData/inspectionsLocal/collections/simplifiableCallChain/joinToStringViaBuilder.kt.after

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+
+val x = listOf(1, 2, 3).joinToString(prefix = "= ", separator = " + ") {
+    val sb = StringBuilder()
+    sb.append(it).append(" + ").append(it)
+    sb
+}

idea/testData/inspectionsLocal/collections/simplifiableCallChain/mapWithReturn.kt

@@ -0,0 +1,9 @@
+// PROBLEM: none
+// WITH_RUNTIME
+
+fun test(args: List<Int>): String {
+    return args.<caret>map {
+        if (it == 0) return ""
+        "$it * $it"
+    }.joinToString(separator = " + ")
+}

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

@@ -139,12 +139,30 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("joinToForHashMap.kt")
+            public void testJoinToForHashMap() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/collections/simplifiableCallChain/joinToForHashMap.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("joinToForMap.kt")
+            public void testJoinToForMap() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/collections/simplifiableCallChain/joinToForMap.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("joinToString.kt")
             public void testJoinToString() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/collections/simplifiableCallChain/joinToString.kt");
                 doTest(fileName);
             }
 
+            @TestMetadata("joinToStringViaBuilder.kt")
+            public void testJoinToStringViaBuilder() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/collections/simplifiableCallChain/joinToStringViaBuilder.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("joinToStringWithReference.kt")
             public void testJoinToStringWithReference() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/collections/simplifiableCallChain/joinToStringWithReference.kt");
@@ -162,6 +180,12 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
                 String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/collections/simplifiableCallChain/mapNotNull.kt");
                 doTest(fileName);
             }
+
+            @TestMetadata("mapWithReturn.kt")
+            public void testMapWithReturn() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/collections/simplifiableCallChain/mapWithReturn.kt");
+                doTest(fileName);
+            }
         }
 
         @TestMetadata("idea/testData/inspectionsLocal/collections/uselessCallOnCollection")