From 41b75346fe2551b574d1f0bb6ccf35f77f08ba2e Mon Sep 17 00:00:00 2001
From: Mikhail Glukhikh <mikhail.glukhikh@jetbrains.com>
Date: Thu, 22 Nov 2018 18:17:56 +0300
Subject: [PATCH] Forbid "introduce backing property" for expect classes
 #KT-28382 Fixed

---
 .../idea/intentions/IntroduceBackingPropertyIntention.kt  | 4 +++-
 .../intentions/introduceBackingProperty/expectClass.kt    | 8 ++++++++
 .../kotlin/idea/intentions/IntentionTestGenerated.java    | 5 +++++
 3 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 idea/testData/intentions/introduceBackingProperty/expectClass.kt

diff --git a/idea/src/org/jetbrains/kotlin/idea/intentions/IntroduceBackingPropertyIntention.kt b/idea/src/org/jetbrains/kotlin/idea/intentions/IntroduceBackingPropertyIntention.kt
index 4318b12cde3..ef4d26b7f3c 100644
--- a/idea/src/org/jetbrains/kotlin/idea/intentions/IntroduceBackingPropertyIntention.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/intentions/IntroduceBackingPropertyIntention.kt
@@ -22,6 +22,7 @@ import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
 import org.jetbrains.kotlin.idea.util.hasJvmFieldAnnotation
+import org.jetbrains.kotlin.idea.util.isExpectDeclaration
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
@@ -48,7 +49,8 @@ class IntroduceBackingPropertyIntention : SelfTargetingIntention<KtProperty>(KtP
             if (bindingContext.get(BindingContext.BACKING_FIELD_REQUIRED, descriptor) == false) return false
 
             val containingClass = property.getStrictParentOfType<KtClassOrObject>() ?: return false
-            return containingClass.declarations.none { it is KtProperty && it.name == "_" + name }
+            if (containingClass.isExpectDeclaration()) return false
+            return containingClass.declarations.none { it is KtProperty && it.name == "_$name" }
         }
 
         fun introduceBackingProperty(property: KtProperty) {
diff --git a/idea/testData/intentions/introduceBackingProperty/expectClass.kt b/idea/testData/intentions/introduceBackingProperty/expectClass.kt
new file mode 100644
index 00000000000..e8f4c34d43e
--- /dev/null
+++ b/idea/testData/intentions/introduceBackingProperty/expectClass.kt
@@ -0,0 +1,8 @@
+// IS_APPLICABLE: false
+// ERROR: The feature "multi platform projects" is experimental and should be enabled explicitly
+
+expect class Outer {
+    class Nested {
+        val <caret>x: Int
+    }
+}
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
index 430b5c61e7a..2e01713e76b 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java
@@ -9299,6 +9299,11 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             runTest("idea/testData/intentions/introduceBackingProperty/const.kt");
         }
 
+        @TestMetadata("expectClass.kt")
+        public void testExpectClass() throws Exception {
+            runTest("idea/testData/intentions/introduceBackingProperty/expectClass.kt");
+        }
+
         @TestMetadata("inapplicableAbstractProperty.kt")
         public void testInapplicableAbstractProperty() throws Exception {
             runTest("idea/testData/intentions/introduceBackingProperty/inapplicableAbstractProperty.kt");