From f39520a220a8cc1d17e4e862a8648a3e4be2f021 Mon Sep 17 00:00:00 2001
From: Eric Traut <erictr@microsoft.com>
Date: Wed, 15 Sep 2021 14:41:53 -0700
Subject: [PATCH] Switched from Map to Set in code flow routine (minor
 cleanup).

---
 packages/pyright-internal/src/analyzer/typeEvaluator.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/pyright-internal/src/analyzer/typeEvaluator.ts b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
index e3d74aadcd7b..c68c9b536ae4 100644
--- a/packages/pyright-internal/src/analyzer/typeEvaluator.ts
+++ b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
@@ -18229,7 +18229,7 @@ export function createTypeEvaluator(
     // is specified, it returns true only if at least one control flow
     // path passes through sourceFlowNode.
     function isFlowNodeReachable(flowNode: FlowNode, sourceFlowNode?: FlowNode): boolean {
-        const visitedFlowNodeMap = new Map<number, true>();
+        const visitedFlowNodeMap = new Set<number>();
 
         function isFlowNodeReachableRecursive(flowNode: FlowNode, sourceFlowNode: FlowNode | undefined): boolean {
             let curFlowNode = flowNode;
@@ -18242,7 +18242,7 @@ export function createTypeEvaluator(
                 }
 
                 // Note that we've been here before.
-                visitedFlowNodeMap.set(curFlowNode.id, true);
+                visitedFlowNodeMap.add(curFlowNode.id);
 
                 if (curFlowNode.flags & FlowFlags.Unreachable) {
                     return false;