diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.java b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.java
index 5f5586cdbed..a7103156fc1 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.java
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.java
@@ -91,7 +91,7 @@ public class InlineCodegen extends CallGenerator {
 
     private final ReifiedTypeInliner reifiedTypeInliner;
 
-    @Nullable
+    @NotNull
     private final TypeParameterMappings typeParameterMappings;
 
     private LambdaInfo activeLambda;
@@ -109,7 +109,7 @@ public class InlineCodegen extends CallGenerator {
             @NotNull GenerationState state,
             @NotNull FunctionDescriptor function,
             @NotNull KtElement callElement,
-            @Nullable TypeParameterMappings typeParameterMappings
+            @NotNull TypeParameterMappings typeParameterMappings
     ) {
         assert InlineUtil.isInline(function) || InlineUtil.isArrayConstructorWithLambda(function) :
                 "InlineCodegen can inline only inline functions and array constructors: " + function;
diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/RootInliningContext.java b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/RootInliningContext.java
deleted file mode 100644
index 31f71b3f54e..00000000000
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/RootInliningContext.java
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * Copyright 2010-2015 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jetbrains.kotlin.codegen.inline;
-
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-import org.jetbrains.kotlin.codegen.context.CodegenContext;
-import org.jetbrains.kotlin.codegen.state.GenerationState;
-import org.jetbrains.kotlin.psi.KtElement;
-
-import java.util.Map;
-
-public class RootInliningContext extends InliningContext {
-    private final InlineCallSiteInfo inlineCallSiteInfo;
-    public final TypeParameterMappings typeParameterMappings;
-    public final KtElement callElement;
-
-    public RootInliningContext(
-            @NotNull Map<Integer, LambdaInfo> map,
-            @NotNull GenerationState state,
-            @NotNull NameGenerator nameGenerator,
-            @NotNull KtElement callElement,
-            @NotNull InlineCallSiteInfo classNameToInline,
-            @NotNull ReifiedTypeInliner inliner,
-            @Nullable TypeParameterMappings typeParameterMappings
-    ) {
-        super(null, map, state, nameGenerator, TypeRemapper.createRoot(typeParameterMappings), inliner, false, false);
-        this.callElement = callElement;
-        this.inlineCallSiteInfo = classNameToInline;
-        this.typeParameterMappings = typeParameterMappings;
-    }
-
-    @NotNull
-    @Override
-    public InlineCallSiteInfo getCallSiteInfo() {
-        return inlineCallSiteInfo;
-    }
-}
diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/RootInliningContext.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/RootInliningContext.kt
new file mode 100644
index 00000000000..b3b9186925b
--- /dev/null
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/RootInliningContext.kt
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2010-2015 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.codegen.inline
+
+import org.jetbrains.kotlin.codegen.state.GenerationState
+import org.jetbrains.kotlin.psi.KtElement
+
+class RootInliningContext(
+        expressionMap: Map<Int, LambdaInfo>,
+        state: GenerationState,
+        nameGenerator: NameGenerator,
+        val callElement: KtElement,
+        override val callSiteInfo: InlineCallSiteInfo,
+        inliner: ReifiedTypeInliner,
+        val typeParameterMappings: TypeParameterMappings
+) : InliningContext(null, expressionMap, state, nameGenerator, TypeRemapper.createRoot(typeParameterMappings), inliner, false, false)