Use star projections to deal with generic subtypes

Author: fwcd

server/src/main/kotlin/org/javacs/kt/completion/Completions.kt

@@ -38,6 +38,7 @@ import org.jetbrains.kotlin.resolve.scopes.utils.parentsWithSelf
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.TypeUtils
 import org.jetbrains.kotlin.types.typeUtil.supertypes
+import org.jetbrains.kotlin.types.typeUtil.replaceArgumentsWithStarProjections
 import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
 import java.util.concurrent.TimeUnit
 
@@ -431,22 +432,14 @@ private fun isParentClass(declaration: DeclarationDescriptor): ClassDescriptor?
     else null
 
 private fun isExtensionFor(type: KotlinType, extensionFunction: CallableDescriptor): Boolean {
-    val receiverType = extensionFunction.extensionReceiverParameter?.type ?: return false
+    val receiverType = extensionFunction.extensionReceiverParameter?.type?.replaceArgumentsWithStarProjections() ?: return false
     return KotlinTypeChecker.DEFAULT.isSubtypeOf(type, receiverType)
         || (TypeUtils.getTypeParameterDescriptorOrNull(receiverType)?.isGenericExtensionFor(type) ?: false)
-        || (TypeUtils.getClassDescriptor(receiverType)?.isClassExtensionFor(type) ?: false)
 }
 
 private fun TypeParameterDescriptor.isGenericExtensionFor(type: KotlinType): Boolean =
     upperBounds.all { KotlinTypeChecker.DEFAULT.isSubtypeOf(type, it) }
 
-// Currently only needed for extensions such as e.g. Collection<T> applied to List<SomeConcreteType>
-// Direct subtype relationships will be detected by KotlinTypeChecker.isSubtypeOf
-private fun ClassDescriptor.isClassExtensionFor(type: KotlinType): Boolean {
-    fun matchesFqName(t: KotlinType) = TypeUtils.getClassDescriptor(t)?.fqNameSafe == fqNameSafe
-    return matchesFqName(type) || type.supertypes().any(::matchesFqName)
-}
-
 private val loggedHidden = CacheBuilder.newBuilder().expireAfterWrite(1, TimeUnit.MINUTES).build<Pair<Name, Name>, Unit>()
 
 private fun logHidden(target: DeclarationDescriptor, from: DeclarationDescriptor) {