if then to elvis: support calling extension function in class #KT-26343 Fixed

idea/src/org/jetbrains/kotlin/idea/intentions/branchedTransformations/IfThenUtils.kt

@@ -43,6 +43,7 @@ import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.resolve.calls.callUtil.getType
+import org.jetbrains.kotlin.resolve.calls.resolvedCallUtil.getExplicitReceiverValue
 import org.jetbrains.kotlin.resolve.calls.resolvedCallUtil.getImplicitReceiverValue
 import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValue
 import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactory
@@ -229,7 +230,11 @@ data class IfThenToSelectData(
         }
     }
 
-    internal fun getImplicitReceiver(): ImplicitReceiver? = baseClause.getResolvedCall(context)?.getImplicitReceiverValue()
+    internal fun getImplicitReceiver(): ImplicitReceiver? {
+        val resolvedCall = baseClause.getResolvedCall(context) ?: return null
+        if (resolvedCall.getExplicitReceiverValue() != null) return null
+        return resolvedCall.getImplicitReceiverValue()
+    }
 
     internal fun hasImplicitReceiver(): Boolean = getImplicitReceiver() != null
 

idea/testData/intentions/branched/ifThenToElvis/extensionFunctionInClass.kt

@@ -0,0 +1,5 @@
+class Foo {
+    fun Foo.bar(): Int = 1
+}
+
+fun Foo.test(foo: Foo?): Int = <caret>if (foo == null) { 0 } else { foo.bar() }

idea/testData/intentions/branched/ifThenToElvis/extensionFunctionInClass.kt.after

@@ -0,0 +1,5 @@
+class Foo {
+    fun Foo.bar(): Int = 1
+}
+
+fun Foo.test(foo: Foo?): Int = foo?.bar() ?: 0

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -2276,6 +2276,11 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
                 runTest("idea/testData/intentions/branched/ifThenToElvis/emptyThenBlock.kt");
             }
 
+            @TestMetadata("extensionFunctionInClass.kt")
+            public void testExtensionFunctionInClass() throws Exception {
+                runTest("idea/testData/intentions/branched/ifThenToElvis/extensionFunctionInClass.kt");
+            }
+
             @TestMetadata("ifAndElseBothInBlocks.kt")
             public void testIfAndElseBothInBlocks() throws Exception {
                 runTest("idea/testData/intentions/branched/ifThenToElvis/ifAndElseBothInBlocks.kt");