diff --git a/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/ConstraintInjector.kt b/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/ConstraintInjector.kt
index 4dad5c63232..6e3f465e622 100644
--- a/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/ConstraintInjector.kt
+++ b/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/ConstraintInjector.kt
@@ -182,6 +182,7 @@ class ConstraintInjector(
 
         // from ConstraintIncorporator.Context
         override fun addNewIncorporatedConstraint(lowerType: KotlinTypeMarker, upperType: KotlinTypeMarker) {
+            if (lowerType === upperType) return
             if (c.isAllowedType(lowerType) && c.isAllowedType(upperType)) {
                 runIsSubtypeOf(lowerType, upperType)
             }