Suggest signature refactoring also for members of expect class

idea/src/org/jetbrains/kotlin/idea/refactoring/suggested/KotlinSuggestedRefactoringAvailability.kt.201

@@ -4,6 +4,7 @@ import com.intellij.openapi.util.Key
 import com.intellij.psi.PsiNamedElement
 import com.intellij.psi.search.LocalSearchScope
 import com.intellij.psi.search.searches.ReferencesSearch
+import com.intellij.psi.util.parents
 import com.intellij.refactoring.suggested.*
 import com.intellij.refactoring.suggested.SuggestedRefactoringSupport.Parameter
 import com.intellij.refactoring.suggested.SuggestedRefactoringSupport.Signature
@@ -14,9 +15,12 @@ import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
 import org.jetbrains.kotlin.idea.refactoring.isInterfaceClass
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.KtCallableDeclaration
+import org.jetbrains.kotlin.psi.KtClassOrObject
+import org.jetbrains.kotlin.psi.KtDeclaration
 import org.jetbrains.kotlin.psi.KtParameter
 import org.jetbrains.kotlin.psi.psiUtil.containingClassOrObject
 import org.jetbrains.kotlin.psi.psiUtil.hasBody
+import org.jetbrains.kotlin.psi.psiUtil.parentsWithSelf
 import org.jetbrains.kotlin.renderer.DescriptorRenderer
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.isError
@@ -211,11 +215,18 @@ class KotlinSuggestedRefactoringAvailability(refactoringSupport: SuggestedRefact
             hasModifier(KtTokens.ABSTRACT_KEYWORD) -> IMPLEMENTATIONS
             hasModifier(KtTokens.OPEN_KEYWORD) -> OVERRIDES
             containingClassOrObject?.isInterfaceClass() == true -> if (hasBody()) OVERRIDES else IMPLEMENTATIONS
-            hasModifier(KtTokens.EXPECT_KEYWORD) -> "actual declarations"
+            isExpectDeclaration() -> "actual declarations"
             else -> null
         }
     }
 
+    private fun KtCallableDeclaration.isExpectDeclaration(): Boolean {
+        return parentsWithSelf
+            .filterIsInstance<KtDeclaration>()
+            .takeWhile { it == this || it is KtClassOrObject }
+            .any { it.hasModifier(KtTokens.EXPECT_KEYWORD) }
+    }
+
     override fun hasTypeChanges(oldSignature: Signature, newSignature: Signature): Boolean {
         return super.hasTypeChanges(oldSignature, newSignature) || oldSignature.receiverType != newSignature.receiverType
     }

idea/tests/org/jetbrains/kotlin/idea/refactoring/suggested/KotlinSuggestedRefactoringAvailabilityTest.kt.201

@@ -530,6 +530,51 @@ class KotlinSuggestedRefactoringAvailabilityTest : BaseSuggestedRefactoringAvail
         )
     }
 
+    fun testExpectedFunction() {
+        ignoreErrors = true
+        doTest(
+            """
+                expect fun foo()<caret>
+            """.trimIndent(),
+            {
+                myFixture.type(": Int")
+            },
+            expectedAvailability = Availability.Available(changeSignatureAvailableTooltip("foo", "actual declarations")),
+        )
+    }
+
+    fun testMemberInsideExpectedClass() {
+        ignoreErrors = true
+        doTest(
+            """
+                expect class C {
+                    fun foo()<caret>
+                }
+            """.trimIndent(),
+            {
+                myFixture.type(": Int")
+            },
+            expectedAvailability = Availability.Available(changeSignatureAvailableTooltip("foo", "actual declarations")),
+        )
+    }
+
+    fun testMemberDeepInsideExpectedClass() {
+        ignoreErrors = true
+        doTest(
+            """
+                expect class C {
+                    class Nested {
+                        fun foo()<caret>
+                    }   
+                }
+            """.trimIndent(),
+            {
+                myFixture.type(": Int")
+            },
+            expectedAvailability = Availability.Available(changeSignatureAvailableTooltip("foo", "actual declarations")),
+        )
+    }
+
     private fun addImport(fqName: String) {
         (file as KtFile).importList!!.add(KtPsiFactory(project).createImportDirective(ImportPath.fromString(fqName)))
     }