NI: take into account an extension function annotation during CST calculation

core/descriptors/src/org/jetbrains/kotlin/types/checker/ClassicTypeSystemContext.kt

@@ -11,11 +11,11 @@ import org.jetbrains.kotlin.builtins.PrimitiveType
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationDescriptor
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
+import org.jetbrains.kotlin.descriptors.annotations.BuiltInAnnotationDescriptor
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.FqNameUnsafe
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.calls.inference.CapturedType
-import org.jetbrains.kotlin.resolve.calls.inference.CapturedTypeConstructorImpl
 import org.jetbrains.kotlin.resolve.constants.IntegerLiteralTypeConstructor
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameUnsafe
 import org.jetbrains.kotlin.resolve.descriptorUtil.hasExactAnnotation
@@ -434,11 +434,17 @@ interface ClassicTypeSystemContext : TypeSystemInferenceExtensionContext, TypeSy
     override fun createSimpleType(
         constructor: TypeConstructorMarker,
         arguments: List<TypeArgumentMarker>,
-        nullable: Boolean
+        nullable: Boolean,
+        isExtensionFunction: Boolean
     ): SimpleTypeMarker {
         require(constructor is TypeConstructor, constructor::errorMessage)
+
+        val annotations = if (isExtensionFunction) {
+            Annotations.create(listOf(BuiltInAnnotationDescriptor(builtIns, FQ_NAMES.extensionFunctionType, emptyMap())))
+        } else Annotations.EMPTY
+
         @Suppress("UNCHECKED_CAST")
-        return KotlinTypeFactory.simpleType(Annotations.EMPTY, constructor, arguments as List<TypeProjection>, nullable)
+        return KotlinTypeFactory.simpleType(annotations, constructor, arguments as List<TypeProjection>, nullable)
     }
 
     override fun createTypeArgument(type: KotlinTypeMarker, variance: TypeVariance): TypeArgumentMarker {
@@ -458,6 +464,11 @@ interface ClassicTypeSystemContext : TypeSystemInferenceExtensionContext, TypeSy
                 this is NewCapturedType
     }
 
+    override fun SimpleTypeMarker.isExtensionFunction(): Boolean {
+        require(this is SimpleType, this::errorMessage)
+        return this.hasAnnotation(FQ_NAMES.extensionFunctionType)
+    }
+
     override fun SimpleTypeMarker.replaceArguments(newArguments: List<TypeArgumentMarker>): SimpleTypeMarker {
         require(this is SimpleType, this::errorMessage)
         @Suppress("UNCHECKED_CAST")

core/type-system/src/org/jetbrains/kotlin/types/model/TypeSystemContext.kt

@@ -56,7 +56,13 @@ interface TypeSystemBuiltInsContext {
 
 interface TypeSystemTypeFactoryContext {
     fun createFlexibleType(lowerBound: SimpleTypeMarker, upperBound: SimpleTypeMarker): KotlinTypeMarker
-    fun createSimpleType(constructor: TypeConstructorMarker, arguments: List<TypeArgumentMarker>, nullable: Boolean): SimpleTypeMarker
+    fun createSimpleType(
+        constructor: TypeConstructorMarker,
+        arguments: List<TypeArgumentMarker>,
+        nullable: Boolean,
+        isExtensionFunction: Boolean = false
+    ): SimpleTypeMarker
+
     fun createTypeArgument(type: KotlinTypeMarker, variance: TypeVariance): TypeArgumentMarker
     fun createStarProjection(typeParameter: TypeParameterMarker): TypeArgumentMarker
 
@@ -88,6 +94,8 @@ interface TypeSystemCommonSuperTypesContext : TypeSystemContext, TypeSystemTypeF
 
     fun KotlinTypeMarker.canHaveUndefinedNullability(): Boolean
 
+    fun SimpleTypeMarker.isExtensionFunction(): Boolean
+
     fun SimpleTypeMarker.typeDepth(): Int
 
     fun KotlinTypeMarker.typeDepth(): Int = when (this) {