diff --git a/core/descriptors/src/org/jetbrains/kotlin/name/ClassId.java b/core/descriptors/src/org/jetbrains/kotlin/name/ClassId.java
index 20929b9527d..13f1a00dae5 100644
--- a/core/descriptors/src/org/jetbrains/kotlin/name/ClassId.java
+++ b/core/descriptors/src/org/jetbrains/kotlin/name/ClassId.java
@@ -108,4 +108,15 @@ public final class ClassId {
         if (packageFqName.isRoot()) return "/" + relativeClassName;
         return packageFqName.toString().replace('.', '/') + "/" + relativeClassName;
     }
+
+    @NotNull
+    public static ClassId fromString(@NotNull String string) {
+        int lastSlash = string.lastIndexOf("/");
+        if (lastSlash == -1) {
+            throw new IllegalArgumentException("Class id should contain slash: " + string);
+        }
+        FqNameUnsafe relativeClassName = new FqNameUnsafe(string.substring(lastSlash + 1));
+        FqName packageFqName = new FqName(string.substring(0, lastSlash).replace('/', '.'));
+        return new ClassId(packageFqName, relativeClassName, false);
+    }
 }
diff --git a/idea/testData/refactoring/rename/renameCompareTo/compareTo.test b/idea/testData/refactoring/rename/renameCompareTo/compareTo.test
index 6ccee8cbbc4..fd6b1a387a6 100644
--- a/idea/testData/refactoring/rename/renameCompareTo/compareTo.test
+++ b/idea/testData/refactoring/rename/renameCompareTo/compareTo.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "compareTo",
   "newName": "foo",
   "mainFile": "compareTo.kt"
diff --git a/idea/testData/refactoring/rename/renameContains/contains.test b/idea/testData/refactoring/rename/renameContains/contains.test
index c80f2715acc..205a31979ae 100644
--- a/idea/testData/refactoring/rename/renameContains/contains.test
+++ b/idea/testData/refactoring/rename/renameContains/contains.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "contains",
   "newName": "foo",
   "mainFile": "contains.kt"
diff --git a/idea/testData/refactoring/rename/renameContainsWithConflicts/containsWithConflicts.test b/idea/testData/refactoring/rename/renameContainsWithConflicts/containsWithConflicts.test
index 719f77c2707..63aee599e88 100644
--- a/idea/testData/refactoring/rename/renameContainsWithConflicts/containsWithConflicts.test
+++ b/idea/testData/refactoring/rename/renameContainsWithConflicts/containsWithConflicts.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "contains",
   "newName": "foo",
   "mainFile": "containsWithConflicts.kt",
diff --git a/idea/testData/refactoring/rename/renameEquals/equals.test b/idea/testData/refactoring/rename/renameEquals/equals.test
index 06ad435519b..8db83e8f0b4 100644
--- a/idea/testData/refactoring/rename/renameEquals/equals.test
+++ b/idea/testData/refactoring/rename/renameEquals/equals.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "equals",
   "newName": "foo",
   "mainFile": "equals.kt"
diff --git a/idea/testData/refactoring/rename/renameExplicitComponentFunction/explicitComponentFunction.test b/idea/testData/refactoring/rename/renameExplicitComponentFunction/explicitComponentFunction.test
index 0c5ed8aea5c..c3eaa94a2ad 100644
--- a/idea/testData/refactoring/rename/renameExplicitComponentFunction/explicitComponentFunction.test
+++ b/idea/testData/refactoring/rename/renameExplicitComponentFunction/explicitComponentFunction.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "component1",
   "newName": "foo",
   "mainFile": "explicitComponentFunction.kt",
diff --git a/idea/testData/refactoring/rename/renameGet/get.test b/idea/testData/refactoring/rename/renameGet/get.test
index 5a018eca58e..467870db426 100644
--- a/idea/testData/refactoring/rename/renameGet/get.test
+++ b/idea/testData/refactoring/rename/renameGet/get.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "get",
   "newName": "foo",
   "mainFile": "get.kt"
diff --git a/idea/testData/refactoring/rename/renameInc/inc.test b/idea/testData/refactoring/rename/renameInc/inc.test
index 1d1f30df8c2..17dfc950877 100644
--- a/idea/testData/refactoring/rename/renameInc/inc.test
+++ b/idea/testData/refactoring/rename/renameInc/inc.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "inc",
   "newName": "foo",
   "mainFile": "inc.kt",
diff --git a/idea/testData/refactoring/rename/renameInvoke/invoke.test b/idea/testData/refactoring/rename/renameInvoke/invoke.test
index 77375211b4f..db1b7391872 100644
--- a/idea/testData/refactoring/rename/renameInvoke/invoke.test
+++ b/idea/testData/refactoring/rename/renameInvoke/invoke.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "invoke",
   "newName": "foo",
   "mainFile": "invoke.kt"
diff --git a/idea/testData/refactoring/rename/renameIterator/iterator.test b/idea/testData/refactoring/rename/renameIterator/iterator.test
index 8fd734de611..c2c4804201e 100644
--- a/idea/testData/refactoring/rename/renameIterator/iterator.test
+++ b/idea/testData/refactoring/rename/renameIterator/iterator.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "iterator",
   "newName": "foo",
   "mainFile": "iterator.kt",
diff --git a/idea/testData/refactoring/rename/renameJavaClass/renameJavaClass.test b/idea/testData/refactoring/rename/renameJavaClass/renameJavaClass.test
index 890ec0bac53..f2981762458 100644
--- a/idea/testData/refactoring/rename/renameJavaClass/renameJavaClass.test
+++ b/idea/testData/refactoring/rename/renameJavaClass/renameJavaClass.test
@@ -1,5 +1,5 @@
 {
   "type": "JAVA_CLASS",
-  "classFQN": "testing.SomeClass",
+  "classId": "testing/SomeClass",
   "newName": "NewName"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameJavaInterface/renameJavaInterface.test b/idea/testData/refactoring/rename/renameJavaInterface/renameJavaInterface.test
index 3f6bba935f0..102b82ac1df 100644
--- a/idea/testData/refactoring/rename/renameJavaInterface/renameJavaInterface.test
+++ b/idea/testData/refactoring/rename/renameJavaInterface/renameJavaInterface.test
@@ -1,6 +1,6 @@
 {
   "type": "JAVA_CLASS",
-  "classFQN": "testing.SomeInterface",
+  "classId": "testing/SomeInterface",
   "newName": "NewInterfaceName",
   "comment": "For KT-4100 Imports doesn't change after java interface name refactoring"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameJavaMethod/javaBaseMethod.test b/idea/testData/refactoring/rename/renameJavaMethod/javaBaseMethod.test
index c27ff5a510b..990339fde22 100644
--- a/idea/testData/refactoring/rename/renameJavaMethod/javaBaseMethod.test
+++ b/idea/testData/refactoring/rename/renameJavaMethod/javaBaseMethod.test
@@ -1,6 +1,6 @@
 {
   "type": "JAVA_METHOD",
-  "classFQN": "testing.JavaClass",
+  "classId": "testing/JavaClass",
   "methodSignature": "String foo()",
   "newName": "bar"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameJavaMethod/kotlinOverridenMethod.test b/idea/testData/refactoring/rename/renameJavaMethod/kotlinOverridenMethod.test
index ba46061895a..2bd314b0255 100644
--- a/idea/testData/refactoring/rename/renameJavaMethod/kotlinOverridenMethod.test
+++ b/idea/testData/refactoring/rename/renameJavaMethod/kotlinOverridenMethod.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "testing.kotlin.KotlinClass",
+  "classId": "testing/kotlin/KotlinClass",
   "oldName": "foo",
   "newName": "bar",
   "mainFile": "MethodUsages.kt"
diff --git a/idea/testData/refactoring/rename/renameKotlinBaseMethod/javaWrapperForBaseFunction.test b/idea/testData/refactoring/rename/renameKotlinBaseMethod/javaWrapperForBaseFunction.test
index 1c23ae82abc..28ce5806da4 100644
--- a/idea/testData/refactoring/rename/renameKotlinBaseMethod/javaWrapperForBaseFunction.test
+++ b/idea/testData/refactoring/rename/renameKotlinBaseMethod/javaWrapperForBaseFunction.test
@@ -1,6 +1,6 @@
 {
   "type": "JAVA_METHOD",
-  "classFQN": "testing.rename.A",
+  "classId": "testing/rename/A",
   "methodSignature": "void first()",
   "newName": "second"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinBaseMethod/javaWrapperForOverridenFunctionWithKotlinBase.test b/idea/testData/refactoring/rename/renameKotlinBaseMethod/javaWrapperForOverridenFunctionWithKotlinBase.test
index 9fe63b7f986..d7bef7a5fc3 100644
--- a/idea/testData/refactoring/rename/renameKotlinBaseMethod/javaWrapperForOverridenFunctionWithKotlinBase.test
+++ b/idea/testData/refactoring/rename/renameKotlinBaseMethod/javaWrapperForOverridenFunctionWithKotlinBase.test
@@ -1,6 +1,6 @@
 {
   "type": "JAVA_METHOD",
-  "classFQN": "testing.JavaClient.D",
+  "classId": "testing/JavaClient.D",
   "methodSignature": "void first()",
   "newName": "second"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinBaseMethod/kotlinBaseFunction.test b/idea/testData/refactoring/rename/renameKotlinBaseMethod/kotlinBaseFunction.test
index ef591a70813..45a35654024 100644
--- a/idea/testData/refactoring/rename/renameKotlinBaseMethod/kotlinBaseFunction.test
+++ b/idea/testData/refactoring/rename/renameKotlinBaseMethod/kotlinBaseFunction.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "testing.rename.A",
+  "classId": "testing/rename/A",
   "oldName": "first",
   "newName": "second",
   "comment": "KT-2836 Rename method with all its implementations"
diff --git a/idea/testData/refactoring/rename/renameKotlinClass/javaWrapperForKotlinClass.test b/idea/testData/refactoring/rename/renameKotlinClass/javaWrapperForKotlinClass.test
index dfb8d1de7bd..c5b5abed02d 100644
--- a/idea/testData/refactoring/rename/renameKotlinClass/javaWrapperForKotlinClass.test
+++ b/idea/testData/refactoring/rename/renameKotlinClass/javaWrapperForKotlinClass.test
@@ -1,5 +1,5 @@
 {
   "type": "JAVA_CLASS",
-  "classFQN": "testing.rename.First",
+  "classId": "testing/rename/First",
   "newName": "Third"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinClass/kotlinClass.test b/idea/testData/refactoring/rename/renameKotlinClass/kotlinClass.test
index 37fa91172bc..dd7c33c5f17 100644
--- a/idea/testData/refactoring/rename/renameKotlinClass/kotlinClass.test
+++ b/idea/testData/refactoring/rename/renameKotlinClass/kotlinClass.test
@@ -1,5 +1,5 @@
 {
   "type": "KOTLIN_CLASS",
-  "classFQN": "testing.rename.First",
+  "classId": "testing/rename/First",
   "newName": "Third"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinClassConstructor/renameKotlinConstructor.test b/idea/testData/refactoring/rename/renameKotlinClassConstructor/renameKotlinConstructor.test
index cf5b0e470e2..604e88d0525 100644
--- a/idea/testData/refactoring/rename/renameKotlinClassConstructor/renameKotlinConstructor.test
+++ b/idea/testData/refactoring/rename/renameKotlinClassConstructor/renameKotlinConstructor.test
@@ -1,5 +1,5 @@
 {
   "type": "KOTLIN_CLASS",
-  "classFQN": "X",
+  "classId": "/X",
   "newName": "TestX"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinClassWithFile/javaClassWrapper.test b/idea/testData/refactoring/rename/renameKotlinClassWithFile/javaClassWrapper.test
index 3cc1e06a8a6..ef552f3cd4a 100644
--- a/idea/testData/refactoring/rename/renameKotlinClassWithFile/javaClassWrapper.test
+++ b/idea/testData/refactoring/rename/renameKotlinClassWithFile/javaClassWrapper.test
@@ -1,5 +1,5 @@
 {
   "type": "JAVA_CLASS",
-  "classFQN": "testing.ClassBefore",
+  "classId": "testing/ClassBefore",
   "newName": "ClassAfter"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinClassWithFile/kotlinClass.test b/idea/testData/refactoring/rename/renameKotlinClassWithFile/kotlinClass.test
index c966523e9f9..78579742dd4 100644
--- a/idea/testData/refactoring/rename/renameKotlinClassWithFile/kotlinClass.test
+++ b/idea/testData/refactoring/rename/renameKotlinClassWithFile/kotlinClass.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_CLASS",
-  "classFQN": "testing.ClassBefore",
+  "classId": "testing/ClassBefore",
   "newName": "ClassAfter",
   "mainFile": "ClassBefore.kt"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinEnum/renameKotlinEnum.test b/idea/testData/refactoring/rename/renameKotlinEnum/renameKotlinEnum.test
index 2e9e726c83b..d92190af2eb 100644
--- a/idea/testData/refactoring/rename/renameKotlinEnum/renameKotlinEnum.test
+++ b/idea/testData/refactoring/rename/renameKotlinEnum/renameKotlinEnum.test
@@ -1,5 +1,5 @@
 {
   "type": "KOTLIN_CLASS",
-  "classFQN": "test.E",
+  "classId": "test/E",
   "newName": "D"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinFunctionInEnum/renameKotlinFunctionInEnum.test b/idea/testData/refactoring/rename/renameKotlinFunctionInEnum/renameKotlinFunctionInEnum.test
index a6826025484..6b82b5f777b 100644
--- a/idea/testData/refactoring/rename/renameKotlinFunctionInEnum/renameKotlinFunctionInEnum.test
+++ b/idea/testData/refactoring/rename/renameKotlinFunctionInEnum/renameKotlinFunctionInEnum.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "test.E",
+  "classId": "test/E",
   "oldName": "foo",
   "newName": "bar"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinMethod/javaWrapperForKotlinMethod.test b/idea/testData/refactoring/rename/renameKotlinMethod/javaWrapperForKotlinMethod.test
index 59a3f619c44..a17176340e6 100644
--- a/idea/testData/refactoring/rename/renameKotlinMethod/javaWrapperForKotlinMethod.test
+++ b/idea/testData/refactoring/rename/renameKotlinMethod/javaWrapperForKotlinMethod.test
@@ -1,6 +1,6 @@
 {
   "type": "JAVA_METHOD",
-  "classFQN": "testing.rename.C",
+  "classId": "testing/rename/C",
   "methodSignature": "int first()",
   "newName": "second",
   "comment": "KT-3256 Can't rename a Kotlin function from Java code"
diff --git a/idea/testData/refactoring/rename/renameKotlinMethod/renameKotlinMethod.test b/idea/testData/refactoring/rename/renameKotlinMethod/renameKotlinMethod.test
index b0b4c5190ca..1829212b581 100644
--- a/idea/testData/refactoring/rename/renameKotlinMethod/renameKotlinMethod.test
+++ b/idea/testData/refactoring/rename/renameKotlinMethod/renameKotlinMethod.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "testing.rename.C",
+  "classId": "testing/rename/C",
   "oldName": "first",
   "newName": "second"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinPackageClass/javaWrapperForKotlinPackageClass.test b/idea/testData/refactoring/rename/renameKotlinPackageClass/javaWrapperForKotlinPackageClass.test
index 3f0b79938c7..e54dc5fb90e 100644
--- a/idea/testData/refactoring/rename/renameKotlinPackageClass/javaWrapperForKotlinPackageClass.test
+++ b/idea/testData/refactoring/rename/renameKotlinPackageClass/javaWrapperForKotlinPackageClass.test
@@ -1,6 +1,6 @@
 {
   "type": "JAVA_CLASS",
   "hint": "Can\u0027t rename kotlin package class",
-  "classFQN": "testing.rename.RenamePackage",
+  "classId": "testing/rename/RenamePackage",
   "newName": "NewPackageName"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinPackageFunctionFromJava/renameKotlinPackageFunctionFromJava.test b/idea/testData/refactoring/rename/renameKotlinPackageFunctionFromJava/renameKotlinPackageFunctionFromJava.test
index 70feefbf1c7..510e30f32b1 100644
--- a/idea/testData/refactoring/rename/renameKotlinPackageFunctionFromJava/renameKotlinPackageFunctionFromJava.test
+++ b/idea/testData/refactoring/rename/renameKotlinPackageFunctionFromJava/renameKotlinPackageFunctionFromJava.test
@@ -1,6 +1,6 @@
 {
   "type": "JAVA_METHOD",
-  "classFQN": "testing.rename.RenamePackage",
+  "classId": "testing/rename/RenamePackage",
   "methodSignature": "int foo()",
   "newName": "bar"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinValProperty/renameAsJavaGetterForExplicitGetter.test b/idea/testData/refactoring/rename/renameKotlinValProperty/renameAsJavaGetterForExplicitGetter.test
index 7d797059863..5aaa7908295 100644
--- a/idea/testData/refactoring/rename/renameKotlinValProperty/renameAsJavaGetterForExplicitGetter.test
+++ b/idea/testData/refactoring/rename/renameKotlinValProperty/renameAsJavaGetterForExplicitGetter.test
@@ -1,6 +1,6 @@
 {
   "type": "JAVA_METHOD",
-  "classFQN": "testing.rename.BP",
+  "classId": "testing/rename/BP",
   "methodSignature": "int getFirst()",
   "newName": "second"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinValProperty/renameBase.test b/idea/testData/refactoring/rename/renameKotlinValProperty/renameBase.test
index 1c05659839e..b45f5bead95 100644
--- a/idea/testData/refactoring/rename/renameKotlinValProperty/renameBase.test
+++ b/idea/testData/refactoring/rename/renameKotlinValProperty/renameBase.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_PROPERTY",
-  "classFQN": "testing.rename.AP",
+  "classId": "testing/rename/AP",
   "oldName": "first",
   "newName": "second"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinValProperty/renameOverriden.test b/idea/testData/refactoring/rename/renameKotlinValProperty/renameOverriden.test
index 6dc1146a601..a9d15bf278f 100644
--- a/idea/testData/refactoring/rename/renameKotlinValProperty/renameOverriden.test
+++ b/idea/testData/refactoring/rename/renameKotlinValProperty/renameOverriden.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_PROPERTY",
-  "classFQN": "testing.rename.CP",
+  "classId": "testing/rename/CP",
   "oldName": "first",
   "newName": "second"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinVarProperty/renameAsJavaGetter.test b/idea/testData/refactoring/rename/renameKotlinVarProperty/renameAsJavaGetter.test
index f46433034e1..b613512f7d0 100644
--- a/idea/testData/refactoring/rename/renameKotlinVarProperty/renameAsJavaGetter.test
+++ b/idea/testData/refactoring/rename/renameKotlinVarProperty/renameAsJavaGetter.test
@@ -1,6 +1,6 @@
 {
   "type": "JAVA_METHOD",
-  "classFQN": "testing.rename.AP",
+  "classId": "testing/rename/AP",
   "methodSignature": "int getFirst()",
   "newName": "second"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinVarProperty/renameAsJavaSetter.test b/idea/testData/refactoring/rename/renameKotlinVarProperty/renameAsJavaSetter.test
index 9e7c32d4031..365752529b0 100644
--- a/idea/testData/refactoring/rename/renameKotlinVarProperty/renameAsJavaSetter.test
+++ b/idea/testData/refactoring/rename/renameKotlinVarProperty/renameAsJavaSetter.test
@@ -1,6 +1,6 @@
 {
   "type": "JAVA_METHOD",
-  "classFQN": "testing.rename.AP",
+  "classId": "testing/rename/AP",
   "methodSignature": "void setFirst(int value)",
   "newName": "second"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinVarProperty/renameBase.test b/idea/testData/refactoring/rename/renameKotlinVarProperty/renameBase.test
index 1c05659839e..b45f5bead95 100644
--- a/idea/testData/refactoring/rename/renameKotlinVarProperty/renameBase.test
+++ b/idea/testData/refactoring/rename/renameKotlinVarProperty/renameBase.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_PROPERTY",
-  "classFQN": "testing.rename.AP",
+  "classId": "testing/rename/AP",
   "oldName": "first",
   "newName": "second"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renameKotlinVarProperty/renameOverriden.test b/idea/testData/refactoring/rename/renameKotlinVarProperty/renameOverriden.test
index e24e5b24769..d0f1ba79588 100644
--- a/idea/testData/refactoring/rename/renameKotlinVarProperty/renameOverriden.test
+++ b/idea/testData/refactoring/rename/renameKotlinVarProperty/renameOverriden.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_PROPERTY",
-  "classFQN": "testing.rename.BP",
+  "classId": "testing/rename/BP",
   "oldName": "first",
   "newName": "second"
 }
\ No newline at end of file
diff --git a/idea/testData/refactoring/rename/renamePlus/plus.test b/idea/testData/refactoring/rename/renamePlus/plus.test
index 894c27a333f..ef2bdd6fffe 100644
--- a/idea/testData/refactoring/rename/renamePlus/plus.test
+++ b/idea/testData/refactoring/rename/renamePlus/plus.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "plus",
   "newName": "foo",
   "mainFile": "plus.kt"
diff --git a/idea/testData/refactoring/rename/renamePlusAssign/plusAssign.test b/idea/testData/refactoring/rename/renamePlusAssign/plusAssign.test
index 26135dac894..acff60600cb 100644
--- a/idea/testData/refactoring/rename/renamePlusAssign/plusAssign.test
+++ b/idea/testData/refactoring/rename/renamePlusAssign/plusAssign.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "plusAssign",
   "newName": "foo",
   "mainFile": "plusAssign.kt"
diff --git a/idea/testData/refactoring/rename/renameSet/set.test b/idea/testData/refactoring/rename/renameSet/set.test
index ab45896ef59..fcc0a727f95 100644
--- a/idea/testData/refactoring/rename/renameSet/set.test
+++ b/idea/testData/refactoring/rename/renameSet/set.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "set",
   "newName": "foo",
   "mainFile": "set.kt"
diff --git a/idea/testData/refactoring/rename/renameSynthesizedComponentFunction/synthesizedComponentFunction.test b/idea/testData/refactoring/rename/renameSynthesizedComponentFunction/synthesizedComponentFunction.test
index 097e87861f0..a675a4c93b5 100644
--- a/idea/testData/refactoring/rename/renameSynthesizedComponentFunction/synthesizedComponentFunction.test
+++ b/idea/testData/refactoring/rename/renameSynthesizedComponentFunction/synthesizedComponentFunction.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_PROPERTY",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "n",
   "newName": "foo",
   "mainFile": "synthesizedComponentFunction.kt"
diff --git a/idea/testData/refactoring/rename/renameUnaryMinus/unaryMinus.test b/idea/testData/refactoring/rename/renameUnaryMinus/unaryMinus.test
index d14734240d6..93e0b1a2a6a 100644
--- a/idea/testData/refactoring/rename/renameUnaryMinus/unaryMinus.test
+++ b/idea/testData/refactoring/rename/renameUnaryMinus/unaryMinus.test
@@ -1,6 +1,6 @@
 {
   "type": "KOTLIN_FUNCTION",
-  "classFQN": "A",
+  "classId": "/A",
   "oldName": "minus",
   "newName": "foo",
   "mainFile": "unaryMinus.kt"
diff --git a/idea/tests/org/jetbrains/kotlin/idea/refactoring/rename/AbstractRenameTest.kt b/idea/tests/org/jetbrains/kotlin/idea/refactoring/rename/AbstractRenameTest.kt
index 2675a1334bc..a861694088b 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/refactoring/rename/AbstractRenameTest.kt
+++ b/idea/tests/org/jetbrains/kotlin/idea/refactoring/rename/AbstractRenameTest.kt
@@ -34,11 +34,8 @@ import com.intellij.psi.JavaPsiFacade
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.module.Module
 import java.util.Collections
-import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
-import org.jetbrains.kotlin.name.FqNameUnsafe
-import org.jetbrains.kotlin.name.isSubpackageOf
 import org.jetbrains.kotlin.idea.refactoring.move.getString
 import org.jetbrains.kotlin.idea.refactoring.move.getNullableString
 import org.jetbrains.kotlin.idea.search.allScope
@@ -47,8 +44,9 @@ import com.intellij.refactoring.BaseRefactoringProcessor.ConflictsInTestsExcepti
 import com.intellij.refactoring.util.CommonRefactoringUtil.RefactoringErrorHintException
 import org.jetbrains.kotlin.idea.KotlinMultiFileTestCase
 import org.jetbrains.kotlin.idea.caches.resolve.analyzeFullyAndGetResult
+import org.jetbrains.kotlin.name.*
 import org.jetbrains.kotlin.resolve.descriptorUtil.resolveTopLevelClass
-import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.serialization.deserialization.findClassAcrossModuleDependencies
 
 private enum class RenameType {
     JAVA_CLASS
@@ -105,7 +103,7 @@ public abstract class AbstractRenameTest : KotlinMultiFileTestCase() {
     }
 
     private fun renameJavaClassTest(renameParamsObject: JsonObject, context: TestContext) {
-        val classFQN = renameParamsObject.getString("classFQN")
+        val classFQN = ClassId.fromString(renameParamsObject.getString("classId")).asSingleFqName().asString()
         val newName = renameParamsObject.getString("newName")
 
         doTestCommittingDocuments { rootDir, rootAfter ->
@@ -117,7 +115,7 @@ public abstract class AbstractRenameTest : KotlinMultiFileTestCase() {
     }
 
     private fun renameJavaMethodTest(renameParamsObject: JsonObject, context: TestContext) {
-        val classFQN = renameParamsObject.getString("classFQN")
+        val classFQN = ClassId.fromString(renameParamsObject.getString("classId")).asSingleFqName().asString()
         val methodSignature = renameParamsObject.getString("methodSignature")
         val newName = renameParamsObject.getString("newName")
 
@@ -182,7 +180,7 @@ public abstract class AbstractRenameTest : KotlinMultiFileTestCase() {
     private fun doRenameInKotlinClass(
             renameParamsObject: JsonObject, context: TestContext, findDescriptorToRename: (ClassDescriptor) -> DeclarationDescriptor
     ) {
-        val classFqName = FqName(renameParamsObject.getString("classFQN"))
+        val classId = ClassId.fromString(renameParamsObject.getString("classId"))
         val newName = renameParamsObject.getString("newName")
         val mainFilePath = renameParamsObject.getNullableString("mainFile") ?: "${getTestDirName(false)}.kt"
 
@@ -192,7 +190,7 @@ public abstract class AbstractRenameTest : KotlinMultiFileTestCase() {
             val jetFile = PsiDocumentManager.getInstance(context.project).getPsiFile(document) as JetFile
 
             val module = jetFile.analyzeFullyAndGetResult().moduleDescriptor
-            val classDescriptor = module.resolveTopLevelClass(classFqName)!!
+            val classDescriptor = module.findClassAcrossModuleDependencies(classId)!!
 
             val psiElement = DescriptorToSourceUtils.descriptorToDeclaration(findDescriptorToRename(classDescriptor))!!