diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.kt
index 841767d95fa..641b3fef6c4 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.kt
@@ -74,7 +74,7 @@ abstract class InlineCodegen<out T : BaseExpressionCodegen>(
             val infos = expandMaskConditionsAndUpdateVariableNodes(
                 node, maskStartIndex, maskValues, methodHandleInDefaultMethodIndex,
                 parameters.parameters.filter { it.functionalArgument === DefaultValueOfInlineParameter }
-                    .mapTo(mutableSetOf()) { parameters.getDeclarationSlot(it) }
+                    .mapTo<_, _, MutableCollection<Int>>(mutableSetOf()) { parameters.getDeclarationSlot(it) }
             )
             for (info in infos) {
                 val lambda = DefaultLambda(info, sourceCompiler, node.name.substringBeforeLast("\$default"))