Revert "FIR: add bfs helper and use it"

This reverts commit dbb0496d23.

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirTypeProvider.kt

@@ -46,7 +46,6 @@ import org.jetbrains.kotlin.psi.KtElement
 import org.jetbrains.kotlin.psi.KtTypeReference
 import org.jetbrains.kotlin.types.TypeApproximatorConfiguration
 import org.jetbrains.kotlin.types.model.CaptureStatus
-import org.jetbrains.kotlin.util.bfs
 
 internal class KtFirTypeProvider(
     override val analysisSession: KtFirAnalysisSession,
@@ -177,7 +176,14 @@ internal class KtFirTypeProvider(
 
     override fun getAllSuperTypes(type: KtType, shouldApproximate: Boolean): List<KtType> {
         require(type is KtFirType)
-        return listOf(type.coneType).bfs { it.getDirectSuperTypes(shouldApproximate).iterator() }.mapTo(mutableListOf()) { it.asKtType() }
+        val queue = type.coneType.getDirectSuperTypes(shouldApproximate).toCollection(ArrayDeque())
+        return buildSet {
+            while (queue.isNotEmpty()) {
+                val current = queue.removeFirst()
+                if (!add(current)) continue
+                queue.addAll(current.getDirectSuperTypes(shouldApproximate))
+            }
+        }.map { it.asKtType() }
     }
 }
 

core/compiler.common/src/org/jetbrains/kotlin/util/containerUtils.kt

@@ -1,23 +0,0 @@
-/*
- * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package org.jetbrains.kotlin.util
-
-/**
- * Perform BFS on the given collection with neighbors created by the given function.
- */
-fun <T> Collection<T>.bfs(getNeighbors: (T) -> Iterator<T>): Sequence<T> {
-    val queue = ArrayDeque(this)
-    val visited = mutableSetOf<T>()
-    return sequence {
-        while (queue.isNotEmpty()) {
-            val current = queue.removeFirst()
-            if (current in visited) continue
-            visited.add(current)
-            yield(current)
-            getNeighbors(current).forEach(queue::add)
-        }
-    }
-}