To reveal odd edgecase

compiler/ir/ir.inline/src/org/jetbrains/kotlin/ir/inline/FunctionInlining.kt

diff --git a/compiler/ir/ir.inline/src/org/jetbrains/kotlin/ir/inline/FunctionInlining.kt b/compiler/ir/ir.inline/src/org/jetbrains/kotlin/ir/inline/FunctionInlining.kt
index 5468e6a..6b450e9 100644
--- a/compiler/ir/ir.inline/src/org/jetbrains/kotlin/ir/inline/FunctionInlining.kt
+++ b/compiler/ir/ir.inline/src/org/jetbrains/kotlin/ir/inline/FunctionInlining.kt
@@ -650,6 +650,7 @@
                 )
             } else if (callSite.extensionReceiver != null) {
                 // Special case: usual lambda is called as lambda with receiver:
+                error ("ACHTUNG!! callSite=${callSite.render()}\ncallee=${callee.render()}")
                 valueArguments.add(0, callSite.extensionReceiver!!)
             }