From 826ae0ed105e14d5bd28fbb6d2e2b34181295175 Mon Sep 17 00:00:00 2001
From: auvred <aauvred@gmail.com>
Date: Mon, 24 Aug 2026 08:18:37 +0300
Subject: [PATCH] Avoid allocations when checking project reference declaration
 directories

---
 tsc/internal/compiler/projectreferencedtsfakinghost.go | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/tsc/internal/compiler/projectreferencedtsfakinghost.go b/tsc/internal/compiler/projectreferencedtsfakinghost.go
index ac3925acb25e8..64a7671b1277e 100644
--- a/tsc/internal/compiler/projectreferencedtsfakinghost.go
+++ b/tsc/internal/compiler/projectreferencedtsfakinghost.go
@@ -223,13 +223,8 @@ func (fs *projectReferenceDtsFakingVfs) fileExistsIfProjectReferenceDts(file str
 
 func (fs *projectReferenceDtsFakingVfs) directoryExistsIfProjectReferenceDeclDir(dir string) core.Tristate {
 	dirPath := fs.toPath(dir)
-	dirPathWithTrailingDirectorySeparator := dirPath + "/"
 	for declDirPath := range fs.dtsDirectories.Keys() {
-		if dirPath == declDirPath ||
-			// Any parent directory of declaration dir
-			strings.HasPrefix(string(declDirPath), string(dirPathWithTrailingDirectorySeparator)) ||
-			// Any directory inside declaration dir
-			strings.HasPrefix(string(dirPath), string(declDirPath)+"/") {
+		if dirPath.ContainsPath(declDirPath) || declDirPath.ContainsPath(dirPath) {
 			return core.TSTrue
 		}
 	}