If-then to safe access: more correct receiver calculation

So #KT-18928 Fixed

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

@@ -88,9 +88,8 @@ fun KtThrowExpression.throwsNullPointerExceptionWithNoArguments(): Boolean {
            && thrownExpression.valueArguments.isEmpty()
 }
 
-fun KtExpression.evaluatesTo(other: KtExpression): Boolean {
-    return this.unwrapBlockOrParenthesis().text == other.text
-}
+fun KtExpression.evaluatesTo(other: KtExpression): Boolean =
+        this.unwrapBlockOrParenthesis().text == other.text
 
 fun KtExpression.convertToIfNotNullExpression(conditionLhs: KtExpression, thenClause: KtExpression, elseClause: KtExpression?): KtIfExpression {
     val condition = KtPsiFactory(this).createExpressionByPattern("$0 != null", conditionLhs)
@@ -102,9 +101,8 @@ fun KtExpression.convertToIfNullExpression(conditionLhs: KtExpression, thenClaus
     return this.convertToIfStatement(condition, thenClause)
 }
 
-fun KtExpression.convertToIfStatement(condition: KtExpression, thenClause: KtExpression, elseClause: KtExpression? = null): KtIfExpression {
-    return replaced(KtPsiFactory(this).createIf(condition, thenClause, elseClause))
-}
+fun KtExpression.convertToIfStatement(condition: KtExpression, thenClause: KtExpression, elseClause: KtExpression? = null): KtIfExpression =
+        replaced(KtPsiFactory(this).createIf(condition, thenClause, elseClause))
 
 fun KtIfExpression.introduceValueForCondition(occurrenceInThenClause: KtExpression, editor: Editor?) {
     val project = this.project
@@ -157,14 +155,17 @@ data class IfThenToSelectData(
         val baseClause: KtExpression?,
         val negatedClause: KtExpression?
 ) {
+    internal fun baseClauseEvaluatesToReceiver() =
+            baseClause?.evaluatesTo(receiverExpression) == true
+
     internal fun replacedBaseClause(factory: KtPsiFactory): KtExpression {
         baseClause ?: error("Base clause must be not-null here")
         val newReceiver = (condition as? KtIsExpression)?.let {
             factory.createExpressionByPattern("$0 as? $1",
-                                              (baseClause as? KtDotQualifiedExpression)?.getLeftMostReceiverExpression() ?: baseClause,
+                                              it.leftHandSide,
                                               it.typeReference!!)
         }
-        return if (baseClause.evaluatesTo(receiverExpression)) {
+        return if (baseClauseEvaluatesToReceiver()) {
             if (condition is KtIsExpression) newReceiver!! else baseClause
         }
         else {
@@ -177,9 +178,8 @@ data class IfThenToSelectData(
         }
     }
 
-    internal fun hasImplicitReceiver(): Boolean {
-        return baseClause.getResolvedCall(context)?.getImplicitReceiverValue() != null
-    }
+    internal fun hasImplicitReceiver(): Boolean =
+            baseClause.getResolvedCall(context)?.getImplicitReceiverValue() != null
 }
 
 internal fun KtIfExpression.buildSelectTransformationData(): IfThenToSelectData? {

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

@@ -40,7 +40,7 @@ class IfThenToSafeAccessIntention : SelfTargetingOffsetIndependentIntention<KtIf
     override fun isApplicableTo(element: KtIfExpression): Boolean {
         val ifThenToSelectData = element.buildSelectTransformationData() ?: return false
         if (!ifThenToSelectData.receiverExpression.isStable(ifThenToSelectData.context)) return false
-        if (ifThenToSelectData.baseClause !is KtDotQualifiedExpression) {
+        if (ifThenToSelectData.baseClauseEvaluatesToReceiver()) {
             text = if (ifThenToSelectData.condition is KtIsExpression) {
                 "Replace 'if' expression with safe cast expression"
             }

idea/testData/intentions/branched/ifThenToSafeAccess/inspectionData/expected.xml

@@ -149,6 +149,22 @@
     <module>light_idea_test_case</module>
     <entry_point TYPE="file" FQNAME="temp:///src/implicitReceiver.kt" />
     <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">If-Then foldable to '?.'</problem_class>
+    <description>Replace 'if' expression with safe access expression</description>
+  </problem>
+  <problem>
+    <file>property.kt</file>
+    <line>10</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/property.kt" />
+    <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">If-Then foldable to '?.'</problem_class>
+    <description>Replace 'if' expression with safe cast expression</description>
+  </problem>
+  <problem>
+    <file>propertyNotNull.kt</file>
+    <line>9</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/propertyNotNull.kt" />
+    <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">If-Then foldable to '?.'</problem_class>
     <description>Remove redundant 'if' expression</description>
   </problem>
 </problems>

idea/testData/intentions/branched/ifThenToSafeAccess/property.kt

@@ -0,0 +1,11 @@
+// IS_APPLICABLE: true
+// INTENTION_TEXT: Replace 'if' expression with safe cast expression
+
+interface Foo
+interface Bar : Foo
+
+data class Data(val foo: Foo)
+
+fun handle(data: Data) {
+    val bar = <caret>if (data.foo is Bar) data.foo else null
+}

idea/testData/intentions/branched/ifThenToSafeAccess/property.kt.after

@@ -0,0 +1,11 @@
+// IS_APPLICABLE: true
+// INTENTION_TEXT: Replace 'if' expression with safe cast expression
+
+interface Foo
+interface Bar : Foo
+
+data class Data(val foo: Foo)
+
+fun handle(data: Data) {
+    val bar = data.foo as? Bar
+}

idea/testData/intentions/branched/ifThenToSafeAccess/propertyNotNull.kt

@@ -0,0 +1,10 @@
+// IS_APPLICABLE: true
+// INTENTION_TEXT: Remove redundant 'if' expression
+
+interface Bar
+
+data class Data(val bar: Bar?)
+
+fun handle(data: Data) {
+    val bar = <caret>if (data.bar != null) data.bar else null
+}

idea/testData/intentions/branched/ifThenToSafeAccess/propertyNotNull.kt.after

@@ -0,0 +1,10 @@
+// IS_APPLICABLE: true
+// INTENTION_TEXT: Remove redundant 'if' expression
+
+interface Bar
+
+data class Data(val bar: Bar?)
+
+fun handle(data: Data) {
+    val bar = data.bar
+}

idea/testData/intentions/branched/ifThenToSafeAccess/propertyWithProperty.kt

@@ -0,0 +1,13 @@
+// IS_APPLICABLE: false
+
+interface Foo
+interface Bar : Foo {
+    val x: String
+}
+
+data class Data(val foo: Foo)
+
+fun handle(data: Data) {
+    // Not available yet (possible in principle)
+    val bar = <caret>if (data.foo is Bar) data.foo.x else null
+}

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

@@ -1774,6 +1774,24 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("property.kt")
+            public void testProperty() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/branched/ifThenToSafeAccess/property.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("propertyNotNull.kt")
+            public void testPropertyNotNull() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/branched/ifThenToSafeAccess/propertyNotNull.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("propertyWithProperty.kt")
+            public void testPropertyWithProperty() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/branched/ifThenToSafeAccess/propertyWithProperty.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("rhsEqualsNull.kt")
             public void testRhsEqualsNull() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/branched/ifThenToSafeAccess/rhsEqualsNull.kt");