diff --git a/kotlin-analysis-api/src/main/kotlin/com/google/devtools/ksp/impl/symbol/kotlin/util.kt b/kotlin-analysis-api/src/main/kotlin/com/google/devtools/ksp/impl/symbol/kotlin/util.kt
index 2455e19ba7..f18d357b24 100644
--- a/kotlin-analysis-api/src/main/kotlin/com/google/devtools/ksp/impl/symbol/kotlin/util.kt
+++ b/kotlin-analysis-api/src/main/kotlin/com/google/devtools/ksp/impl/symbol/kotlin/util.kt
@@ -608,7 +608,11 @@ internal fun KaValueParameterSymbol.getDefaultValue(): KaAnnotationValue? {
 internal fun fillInDeepSubstitutor(context: KaType, substitutorBuilder: KaSubstitutorBuilder) {
     val unwrappedType = when (context) {
         is KaClassType -> context
-        is KaFlexibleType -> context.lowerBound as? KaClassType ?: return
+        is KaFlexibleType -> {
+            fillInDeepSubstitutor(context.upperBound, substitutorBuilder)
+            fillInDeepSubstitutor(context.lowerBound, substitutorBuilder)
+            return
+        }
         else -> return
     }
     val parameters = unwrappedType.symbol.typeParameters
diff --git a/kotlin-analysis-api/testData/asMemberOf.kt b/kotlin-analysis-api/testData/asMemberOf.kt
index 80b5e92702..d334058d2f 100644
--- a/kotlin-analysis-api/testData/asMemberOf.kt
+++ b/kotlin-analysis-api/testData/asMemberOf.kt
@@ -18,6 +18,18 @@
 // WITH_RUNTIME
 // TEST PROCESSOR: AsMemberOfProcessor
 // EXPECTED:
+// main.Test: MutableIterator<(String..String?)>
+// main.Test: Iterator<(String..String?)>
+// main.Test: MutableIterator<(String..String?)>
+// lib.Test: MutableIterator<(String..String?)>
+// lib.Test: Iterator<(String..String?)>
+// lib.Test: MutableIterator<(String..String?)>
+// main.TestKt: MutableIterator<String>
+// main.TestKt: Iterator<String>
+// main.TestKt: MutableIterator<String>
+// lib.TestKt: MutableIterator<String>
+// lib.TestKt: Iterator<String>
+// lib.TestKt: MutableIterator<String>
 // Child1!!
 // intType: kotlin.Int!!
 // baseTypeArg1: kotlin.Int!!
diff --git a/test-utils/src/main/kotlin/com/google/devtools/ksp/processor/AsMemberOfProcessor.kt b/test-utils/src/main/kotlin/com/google/devtools/ksp/processor/AsMemberOfProcessor.kt
index 5fe8c08316..655cb5cf51 100644
--- a/test-utils/src/main/kotlin/com/google/devtools/ksp/processor/AsMemberOfProcessor.kt
+++ b/test-utils/src/main/kotlin/com/google/devtools/ksp/processor/AsMemberOfProcessor.kt
@@ -19,14 +19,17 @@ class AsMemberOfProcessor : AbstractTestProcessor() {
 
         listOf("main.Test", "lib.Test", "main.TestKt", "lib.TestKt").forEach { clsName ->
             resolver.getClassDeclarationByName(clsName)!!.let { cls ->
-                val listType = cls.getAllFunctions().single {it.simpleName.asString() == "f"}.returnType!!.resolve()
+                val listType = cls.getAllFunctions().single { it.simpleName.asString() == "f" }.returnType!!.resolve()
                 val listDecl = listType.declaration as KSClassDeclaration
                 val iterator = listDecl.getAllFunctions().single { it.simpleName.asString() == "iterator" }
-                println("$clsName: ${iterator.asMemberOf(listType).returnType}")
-                val listIterator = resolver.getClassDeclarationByName("kotlin.collections.List")!!.getDeclaredFunctions().single { it.simpleName.asString() == "iterator" }
-                println("$clsName: ${listIterator.asMemberOf(listType).returnType}")
-                val mutableListIterator = resolver.getClassDeclarationByName("kotlin.collections.MutableCollection")!!.getDeclaredFunctions().single { it.simpleName.asString() == "iterator" }
-                println("$clsName: ${mutableListIterator.asMemberOf(listType).returnType}")
+                results.add("$clsName: ${iterator.asMemberOf(listType).returnType}")
+                val listIterator = resolver.getClassDeclarationByName("kotlin.collections.List")!!
+                    .getDeclaredFunctions().single { it.simpleName.asString() == "iterator" }
+                results.add("$clsName: ${listIterator.asMemberOf(listType).returnType}")
+                val mutableListIterator =
+                    resolver.getClassDeclarationByName("kotlin.collections.MutableCollection")!!
+                        .getDeclaredFunctions().single { it.simpleName.asString() == "iterator" }
+                results.add("$clsName: ${mutableListIterator.asMemberOf(listType).returnType}")
             }
         }
 
diff --git a/test-utils/testData/api/asMemberOf.kt b/test-utils/testData/api/asMemberOf.kt
index 0c4e5fa74d..cd2ade6b8b 100644
--- a/test-utils/testData/api/asMemberOf.kt
+++ b/test-utils/testData/api/asMemberOf.kt
@@ -18,6 +18,18 @@
 // WITH_RUNTIME
 // TEST PROCESSOR: AsMemberOfProcessor
 // EXPECTED:
+// main.Test: MutableIterator<(String..String?)>
+// main.Test: Iterator<(String..String?)>
+// main.Test: MutableIterator<(String..String?)>
+// lib.Test: MutableIterator<(String..String?)>
+// lib.Test: Iterator<(String..String?)>
+// lib.Test: MutableIterator<(String..String?)>
+// main.TestKt: MutableIterator<String>
+// main.TestKt: Iterator<String>
+// main.TestKt: MutableIterator<String>
+// lib.TestKt: MutableIterator<String>
+// lib.TestKt: Iterator<String>
+// lib.TestKt: MutableIterator<String>
 // Child1!!
 // intType: kotlin.Int!!
 // baseTypeArg1: kotlin.Int!!