Create from Usage: Fix generation of extensions with nullable receiver

#KT-23796 Fixed

idea/src/org/jetbrains/kotlin/idea/quickfix/createFromUsage/callableBuilder/CallableBuilder.kt

@@ -77,6 +77,7 @@ import org.jetbrains.kotlin.types.Variance
 import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
 import org.jetbrains.kotlin.types.typeUtil.isAnyOrNullableAny
 import org.jetbrains.kotlin.types.typeUtil.isUnit
+import org.jetbrains.kotlin.types.typeUtil.makeNullable
 import java.lang.AssertionError
 import java.lang.IllegalArgumentException
 import java.lang.IllegalStateException
@@ -243,6 +244,7 @@ class CallableBuilder(val config: CallableBuilderConfiguration) {
             // gather relevant information
 
             val placement = placement
+            var nullableReceiver = false
             when (placement) {
                 is CallablePlacement.NoReceiver -> {
                     containingElement = placement.containingElement
@@ -255,14 +257,17 @@ class CallableBuilder(val config: CallableBuilderConfiguration) {
                     }
                 }
                 is CallablePlacement.WithReceiver -> {
-                    receiverClassDescriptor =
+                    val theType = placement.receiverTypeCandidate.theType
-                            placement.receiverTypeCandidate.theType.constructor.declarationDescriptor
+                    nullableReceiver = theType.isMarkedNullable
+                    receiverClassDescriptor = theType.constructor.declarationDescriptor
                     val classDeclaration = receiverClassDescriptor?.let { DescriptorToSourceUtils.getSourceFromDescriptor(it) }
                     containingElement = if (!config.isExtension && classDeclaration != null) classDeclaration else config.currentFile
                 }
                 else -> throw IllegalArgumentException("Placement wan't initialized")
             }
-            val receiverType = receiverClassDescriptor?.defaultType
+            val receiverType = receiverClassDescriptor?.defaultType?.let {
+                if (nullableReceiver) it.makeNullable() else it
+            }
 
             val project = config.currentFile.project
 

idea/src/org/jetbrains/kotlin/idea/quickfix/createFromUsage/callableBuilder/CallableBuilder.kt.172

@@ -77,6 +77,7 @@ import org.jetbrains.kotlin.types.Variance
 import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
 import org.jetbrains.kotlin.types.typeUtil.isAnyOrNullableAny
 import org.jetbrains.kotlin.types.typeUtil.isUnit
+import org.jetbrains.kotlin.types.typeUtil.makeNullable
 import java.lang.AssertionError
 import java.lang.IllegalArgumentException
 import java.lang.IllegalStateException
@@ -243,6 +244,7 @@ class CallableBuilder(val config: CallableBuilderConfiguration) {
             // gather relevant information
 
             val placement = placement
+            var nullableReceiver = false
             when (placement) {
                 is CallablePlacement.NoReceiver -> {
                     containingElement = placement.containingElement
@@ -255,14 +257,17 @@ class CallableBuilder(val config: CallableBuilderConfiguration) {
                     }
                 }
                 is CallablePlacement.WithReceiver -> {
-                    receiverClassDescriptor =
+                    val theType = placement.receiverTypeCandidate.theType
-                            placement.receiverTypeCandidate.theType.constructor.declarationDescriptor
+                    nullableReceiver = theType.isMarkedNullable
+                    receiverClassDescriptor = theType.constructor.declarationDescriptor
                     val classDeclaration = receiverClassDescriptor?.let { DescriptorToSourceUtils.getSourceFromDescriptor(it) }
                     containingElement = if (!config.isExtension && classDeclaration != null) classDeclaration else config.currentFile
                 }
                 else -> throw IllegalArgumentException("Placement wan't initialized")
             }
-            val receiverType = receiverClassDescriptor?.defaultType
+            val receiverType = receiverClassDescriptor?.defaultType?.let {
+                if (nullableReceiver) it.makeNullable() else it
+            }
 
             val project = config.currentFile.project
 

idea/testData/quickfix/createFromUsage/createFunction/call/nullableReceiver.kt

@@ -0,0 +1,4 @@
+// "Create extension function 'String?.notExistingFun'" "true"
+fun context(p: String?) {
+    p.<caret>notExistingFun()
+}

idea/testData/quickfix/createFromUsage/createFunction/call/nullableReceiver.kt.after

@@ -0,0 +1,8 @@
+// "Create extension function 'String?.notExistingFun'" "true"
+fun context(p: String?) {
+    p.notExistingFun()
+}
+
+private fun String?.notExistingFun() {
+    TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
+}

idea/testData/quickfix/createFromUsage/createVariable/property/nullableReceiver.kt

@@ -0,0 +1,6 @@
+// "Create extension property 'String?.notExistingVal'" "true"
+fun foo(n: Int) {}
+
+fun context(p: String?) {
+    foo(p.<caret>notExistingVal)
+}

idea/testData/quickfix/createFromUsage/createVariable/property/nullableReceiver.kt.after

@@ -0,0 +1,11 @@
+// "Create extension property 'String?.notExistingVal'" "true"
+fun foo(n: Int) {}
+
+fun context(p: String?) {
+    foo(p.notExistingVal)
+}
+
+private val String?.notExistingVal: Int
+    get() {
+        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java

@@ -3084,6 +3084,12 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
                     runTest("idea/testData/quickfix/createFromUsage/createFunction/call/notExactArgument.kt");
                 }
 
+                @TestMetadata("nullableReceiver.kt")
+                public void testNullableReceiver() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/createFromUsage/createFunction/call/nullableReceiver.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("objectMemberFunNoReceiver.kt")
                 public void testObjectMemberFunNoReceiver() throws Exception {
                     runTest("idea/testData/quickfix/createFromUsage/createFunction/call/objectMemberFunNoReceiver.kt");
@@ -4599,6 +4605,12 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
                     runTest("idea/testData/quickfix/createFromUsage/createVariable/property/nonAbstractInInterface.kt");
                 }
 
+                @TestMetadata("nullableReceiver.kt")
+                public void testNullableReceiver() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/createFromUsage/createVariable/property/nullableReceiver.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("objectMemberValNoReceiver.kt")
                 public void testObjectMemberValNoReceiver() throws Exception {
                     runTest("idea/testData/quickfix/createFromUsage/createVariable/property/objectMemberValNoReceiver.kt");