Extraction Engine: Respect smart casts applied to "this" references

#KT-7447

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/extractionEngine/extractableAnalysisUtil.kt

@@ -69,8 +69,10 @@ import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 import org.jetbrains.kotlin.resolve.bindingContextUtil.isUsedAsStatement
 import org.jetbrains.kotlin.resolve.calls.CallTransformer
 import org.jetbrains.kotlin.resolve.calls.callUtil.getCalleeExpressionIfAny
+import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactory
 import org.jetbrains.kotlin.resolve.scopes.JetScope
 import org.jetbrains.kotlin.resolve.scopes.JetScopeUtils
+import org.jetbrains.kotlin.resolve.scopes.receivers.ExpressionReceiver
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
 import org.jetbrains.kotlin.resolve.scopes.receivers.ThisReceiver
 import org.jetbrains.kotlin.types.*
@@ -642,13 +644,27 @@ private fun ExtractionData.inferParametersInfo(
 
             val extractParameter = extractThis || extractLocalVar
             if (extractParameter) {
-                val parameterType = when {
+                val parameterExpression = when {
-                    receiverToExtract.exists() -> receiverToExtract.getType()
+                    receiverToExtract is ExpressionReceiver -> receiverToExtract.getExpression()
-                    else -> bindingContext[BindingContext.SMARTCAST, originalRef]
+                    receiverToExtract.exists() -> null
-                            ?: bindingContext[BindingContext.EXPRESSION_TYPE, originalRef]
+                    else -> (originalRef.getParent() as? JetThisExpression) ?: originalRef
-                            ?: DEFAULT_PARAMETER_TYPE
                 }
 
+                val parameterType = when {
+                    parameterExpression != null -> bindingContext[BindingContext.SMARTCAST, parameterExpression]
+                                                   ?: bindingContext[BindingContext.EXPRESSION_TYPE, parameterExpression]
+                                                   ?: if (receiverToExtract.exists()) receiverToExtract.getType() else null
+                    receiverToExtract is ThisReceiver -> {
+                        val calleeExpression = resolvedCall!!.getCall().getCalleeExpression()
+                        bindingContext[BindingContext.EXPRESSION_DATA_FLOW_INFO, calleeExpression]?.let { dataFlowInfo ->
+                            val possibleTypes = dataFlowInfo.getPossibleTypes(DataFlowValueFactory.createDataFlowValue(receiverToExtract))
+                            CommonSupertypes.commonSupertype(possibleTypes)
+                        } ?: receiverToExtract.getType()
+                    }
+                    receiverToExtract.exists() -> receiverToExtract.getType()
+                    else -> null
+                } ?: DEFAULT_PARAMETER_TYPE
+
                 val parameter = extractedDescriptorToParameter.getOrPut(descriptorToExtract) {
                     val argumentText =
                             if (hasThisReceiver && extractThis) {

idea/testData/refactoring/extractFunction/parameters/extractThis/explicitThisWithSmartCast.kt

@@ -0,0 +1,17 @@
+// SUGGESTED_NAMES: i, getB
+// PARAM_DESCRIPTOR: internal fun A.ext(): kotlin.Unit defined in root package
+// PARAM_TYPES: B
+fun main(args: Array<String>) {
+    val a: A = B()
+    a.ext()
+}
+
+fun A.ext() {
+    if (this !is B) return
+    val b = <selection>this.foo()</selection>
+}
+
+open class A
+class B: A() {
+    fun foo() = 1
+}

idea/testData/refactoring/extractFunction/parameters/extractThis/explicitThisWithSmartCast.kt.after

@@ -0,0 +1,19 @@
+// SUGGESTED_NAMES: i, getB
+// PARAM_DESCRIPTOR: internal fun A.ext(): kotlin.Unit defined in root package
+// PARAM_TYPES: B
+fun main(args: Array<String>) {
+    val a: A = B()
+    a.ext()
+}
+
+fun A.ext() {
+    if (this !is B) return
+    val b = i()
+}
+
+private fun B.i() = this.foo()
+
+open class A
+class B: A() {
+    fun foo() = 1
+}

idea/testData/refactoring/extractFunction/parameters/extractThis/implicitThisWithSmartCast.kt

@@ -0,0 +1,17 @@
+// SUGGESTED_NAMES: i, getB
+// PARAM_DESCRIPTOR: internal fun A.ext(): kotlin.Unit defined in root package
+// PARAM_TYPES: B
+fun main(args: Array<String>) {
+    val a: A = B()
+    a.ext()
+}
+
+fun A.ext() {
+    if (this !is B) return
+    val b = <selection>foo()</selection>
+}
+
+open class A
+class B: A() {
+    fun foo() = 1
+}

idea/testData/refactoring/extractFunction/parameters/extractThis/implicitThisWithSmartCast.kt.after

@@ -0,0 +1,19 @@
+// SUGGESTED_NAMES: i, getB
+// PARAM_DESCRIPTOR: internal fun A.ext(): kotlin.Unit defined in root package
+// PARAM_TYPES: B
+fun main(args: Array<String>) {
+    val a: A = B()
+    a.ext()
+}
+
+fun A.ext() {
+    if (this !is B) return
+    val b = i()
+}
+
+private fun B.i() = foo()
+
+open class A
+class B: A() {
+    fun foo() = 1
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/introduce/JetExtractionTestGenerated.java

@@ -1643,6 +1643,12 @@ public class JetExtractionTestGenerated extends AbstractJetExtractionTest {
                     doExtractFunctionTest(fileName);
                 }
 
+                @TestMetadata("explicitThisWithSmartCast.kt")
+                public void testExplicitThisWithSmartCast() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/parameters/extractThis/explicitThisWithSmartCast.kt");
+                    doExtractFunctionTest(fileName);
+                }
+
                 @TestMetadata("implicitAndExplicitLabeledThisInMember.kt")
                 public void testImplicitAndExplicitLabeledThisInMember() throws Exception {
                     String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/parameters/extractThis/implicitAndExplicitLabeledThisInMember.kt");
@@ -1667,6 +1673,12 @@ public class JetExtractionTestGenerated extends AbstractJetExtractionTest {
                     doExtractFunctionTest(fileName);
                 }
 
+                @TestMetadata("implicitThisWithSmartCast.kt")
+                public void testImplicitThisWithSmartCast() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/parameters/extractThis/implicitThisWithSmartCast.kt");
+                    doExtractFunctionTest(fileName);
+                }
+
                 @TestMetadata("qualifiedThisAsArgument.kt")
                 public void testQualifiedThisAsArgument() throws Exception {
                     String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/parameters/extractThis/qualifiedThisAsArgument.kt");