Unused symbol: don't suggest actual declaration used in another platform

Related to KT-17512
Related to KT-15666

idea/src/org/jetbrains/kotlin/idea/inspections/UnusedSymbolInspection.kt

@@ -50,6 +50,7 @@ import org.jetbrains.kotlin.idea.imports.importableFqName
 import org.jetbrains.kotlin.idea.quickfix.RemoveUnusedFunctionParameterFix
 import org.jetbrains.kotlin.idea.references.mainReference
 import org.jetbrains.kotlin.idea.references.resolveMainReferenceToDescriptors
+import org.jetbrains.kotlin.idea.search.ideaExtensions.KotlinReferencesSearchOptions
 import org.jetbrains.kotlin.idea.search.ideaExtensions.KotlinReferencesSearchParameters
 import org.jetbrains.kotlin.idea.search.isCheapEnoughToSearchConsideringOperators
 import org.jetbrains.kotlin.idea.search.projectScope
@@ -281,7 +282,11 @@ class UnusedSymbolInspection : AbstractKotlinInspection() {
             return false
         }
 
-        val searchParameters = KotlinReferencesSearchParameters(declaration, useScope)
+        val searchParameters = KotlinReferencesSearchParameters(
+            declaration,
+            useScope,
+            kotlinOptions = KotlinReferencesSearchOptions(acceptCallableOverrides = declaration.hasActualModifier())
+        )
         val referenceUsed: Boolean by lazy { !ReferencesSearch.search(searchParameters).forEach(::checkReference) }
 
         if (descriptor is FunctionDescriptor &&

idea/testData/multiModuleQuickFix/safeDeleteUsedInAnotherPlatform/common/common.kt

@@ -0,0 +1,3 @@
+expect class My constructor() {
+    fun foo()
+}

idea/testData/multiModuleQuickFix/safeDeleteUsedInAnotherPlatform/common/common.kt.after

@@ -0,0 +1,3 @@
+expect class My constructor() {
+    fun foo()
+}

idea/testData/multiModuleQuickFix/safeDeleteUsedInAnotherPlatform/js/js.kt

@@ -0,0 +1,7 @@
+actual class My {
+    actual fun foo() {}
+}
+
+fun test() {
+    My().foo()
+}

idea/testData/multiModuleQuickFix/safeDeleteUsedInAnotherPlatform/js/js.kt.after

@@ -0,0 +1,7 @@
+actual class My {
+    actual fun foo() {}
+}
+
+fun test() {
+    My().foo()
+}

idea/testData/multiModuleQuickFix/safeDeleteUsedInAnotherPlatform/jvm/jvm.kt

@@ -0,0 +1,8 @@
+// "Safe delete 'foo'" "false"
+// TOOL: org.jetbrains.kotlin.idea.inspections.UnusedSymbolInspection
+// ACTION: Convert member to extension
+// ACTION: Move to companion object
+
+actual class My {
+    actual fun <caret>foo() {}
+}

idea/testData/multiModuleQuickFix/safeDeleteUsedInAnotherPlatform/jvm/jvm.kt.after

@@ -0,0 +1,8 @@
+// "Safe delete 'foo'" "false"
+// TOOL: org.jetbrains.kotlin.idea.inspections.UnusedSymbolInspection
+// ACTION: Convert member to extension
+// ACTION: Move to companion object
+
+actual class My {
+    actual fun foo() {}
+}

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixMultiModuleTestGenerated.java

@@ -344,6 +344,11 @@ public class QuickFixMultiModuleTestGenerated extends AbstractQuickFixMultiModul
         runTest("idea/testData/multiModuleQuickFix/safeDeleteFromActual/");
     }
 
+    @TestMetadata("safeDeleteUsedInAnotherPlatform")
+    public void testSafeDeleteUsedInAnotherPlatform() throws Exception {
+        runTest("idea/testData/multiModuleQuickFix/safeDeleteUsedInAnotherPlatform/");
+    }
+
     @TestMetadata("sealed")
     public void testSealed() throws Exception {
         runTest("idea/testData/multiModuleQuickFix/sealed/");