diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/DiagnosticReporterByTrackingStrategy.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/DiagnosticReporterByTrackingStrategy.kt
index e5ee3c81d1c..b10820174e8 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/DiagnosticReporterByTrackingStrategy.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/DiagnosticReporterByTrackingStrategy.kt
@@ -464,7 +464,7 @@ class DiagnosticReporterByTrackingStrategy(
                 val parameter = lambdaExpression.valueParameters.getOrNull(index) ?: return@lambda
                 val diagnosticFactory =
                     if (isWarning) EXPECTED_PARAMETER_TYPE_MISMATCH_WARNING else EXPECTED_PARAMETER_TYPE_MISMATCH
-                report(diagnosticFactory.on(parameter, error.upperKotlinType))
+                report(diagnosticFactory.on(parameter, error.lowerKotlinType))
                 return
             }