From 4c6ea7c26a4fccabafd8e714555ea91d3282936f Mon Sep 17 00:00:00 2001
From: Roman Golyshev <roman.golyshev@jetbrains.com>
Date: Thu, 12 Mar 2020 16:34:00 +0300
Subject: [PATCH] KT-36808 Sink down member function `Flow.collect` in the
 completion

- This method is never supposed to be called, so we try to lower its
presence in the completion list by puting it on the last possible
position
- ^KT-36808 Fixed
---
 .../kotlin/idea/completion/CompletionSession.kt  |  2 ++
 .../jetbrains/kotlin/idea/completion/Weighers.kt | 16 ++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/CompletionSession.kt b/idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/CompletionSession.kt
index 5bfb93e7698..1db3cd760c6 100644
--- a/idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/CompletionSession.kt
+++ b/idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/CompletionSession.kt
@@ -284,6 +284,8 @@ abstract class CompletionSession(
 
         sorter = sorter.weighAfter("kotlin.proximity", ByNameAlphabeticalWeigher, PreferLessParametersWeigher)
 
+        sorter = sorter.weighBefore("prefix", KotlinUnwantedLookupElementWeigher)
+
         sorter = if (expectedInfos.all { it.fuzzyType?.type?.isUnit() == true }) {
             sorter.weighBefore("prefix", PreferDslMembers)
         } else {
diff --git a/idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/Weighers.kt b/idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/Weighers.kt
index 3155a5ac94e..ac0cbed5f77 100644
--- a/idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/Weighers.kt
+++ b/idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/Weighers.kt
@@ -22,7 +22,9 @@ import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
 import org.jetbrains.kotlin.idea.util.CallType
 import org.jetbrains.kotlin.idea.util.CallTypeAndReceiver
 import org.jetbrains.kotlin.idea.util.toFuzzyType
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.resolve.descriptorUtil.parentsWithSelf
 import org.jetbrains.kotlin.resolve.findOriginalTopMostOverriddenDescriptors
 import org.jetbrains.kotlin.types.typeUtil.isNothing
@@ -222,6 +224,20 @@ object DeprecatedWeigher : LookupElementWeigher("kotlin.deprecated") {
     }
 }
 
+/**
+ * This weigher is designed to "sink down" specific elements in completion.
+ *
+ * For now it only works on "Flow.collect" member method (see [https://youtrack.jetbrains.com/issue/KT-36808] for details).
+ */
+object KotlinUnwantedLookupElementWeigher : LookupElementWeigher("kotlin.unwantedElement") {
+    private val flowCollectFqName = FqName("kotlinx.coroutines.flow.Flow.collect")
+
+    override fun weigh(element: LookupElement): Int {
+        val descriptor = (element.`object` as? DeclarationLookupObject)?.descriptor ?: return 0
+        return if (descriptor.fqNameSafe == flowCollectFqName) 1 else 0
+    }
+}
+
 object PreferMatchingItemWeigher : LookupElementWeigher("kotlin.preferMatching", false, true) {
     private enum class Weight {
         keywordExactMatch,