@@ -125,7 +125,8 @@ type processedFiles struct {
 	sourceFileMetaDatas           map[tspath.Path]ast.SourceFileMetaData
 	jsxRuntimeImportSpecifiers    map[tspath.Path]*jsxRuntimeImportSpecifier
 	importHelpersImportSpecifiers map[tspath.Path]*ast.StringLiteralNode
-	libFiles                      map[tspath.Path]*LibFile
+	libFiles                      map[string]*ast.SourceFile
+	libFilesByPath                map[tspath.Path]*LibFile
 	// List of present unsupported extensions
 	sourceFilesFoundSearchingNodeModules collections.Set[tspath.Path]
 	includeProcessor                     *includeProcessor
 
@@ -357,7 +357,8 @@ func (w *filesParser) getProcessedFiles(loader *fileLoader) processedFiles {
 	var jsxRuntimeImportSpecifiers map[tspath.Path]*jsxRuntimeImportSpecifier
 	var importHelpersImportSpecifiers map[tspath.Path]*ast.StringLiteralNode
 	var sourceFilesFoundSearchingNodeModules collections.Set[tspath.Path]
-	libFilesMap := make(map[tspath.Path]*LibFile, libFileCount)
+	libFilesMap := make(map[string]*ast.SourceFile, libFileCount)
+	libFilesByPath := make(map[tspath.Path]*LibFile, libFileCount)
 
 	var redirectTargetsMap map[tspath.Path][]string
 	var redirectFilesByPath map[tspath.Path]*redirectsFile
@@ -515,7 +516,8 @@ func (w *filesParser) getProcessedFiles(loader *fileLoader) processedFiles {
 
 			if task.libFile != nil {
 				libFiles = append(libFiles, file)
-				libFilesMap[path] = task.libFile
+				libFilesMap[task.libFile.Name] = file
+				libFilesByPath[path] = task.libFile
 			} else {
 				files = append(files, file)
 			}
@@ -576,6 +578,7 @@ func (w *filesParser) getProcessedFiles(loader *fileLoader) processedFiles {
 		importHelpersImportSpecifiers:        importHelpersImportSpecifiers,
 		sourceFilesFoundSearchingNodeModules: sourceFilesFoundSearchingNodeModules,
 		libFiles:                             libFilesMap,
+		libFilesByPath:                       libFilesByPath,
 		missingFiles:                         missingFiles,
 		includeProcessor:                     includeProcessor,
 		outputFileToProjectReferenceSource:   outputFileToProjectReferenceSource,
 
@@ -1710,7 +1710,7 @@ func (p *Program) GetDefaultResolutionModeForFile(sourceFile ast.HasFileName) co
 }
 
 func (p *Program) IsSourceFileDefaultLibrary(path tspath.Path) bool {
-	_, ok := p.libFiles[path]
+	_, ok := p.libFilesByPath[path]
 	return ok
 }
 
@@ -1722,7 +1722,7 @@ func (p *Program) IsGlobalTypingsFile(fileName string) bool {
 }
 
 func (p *Program) GetDefaultLibFile(path tspath.Path) *LibFile {
-	if libFile, ok := p.libFiles[path]; ok {
+	if libFile, ok := p.libFilesByPath[path]; ok {
 		return libFile
 	}
 	return nil
@@ -2091,12 +2091,7 @@ func (p *Program) GetLibFileFromReference(ref *ast.FileReference) *ast.SourceFil
 	if !ok {
 		return nil
 	}
-	for path, libFile := range p.libFiles {
-		if libFile.Name == name {
-			return p.filesByPath[path]
-		}
-	}
-	return nil
+	return p.libFiles[name]
 }
 
 func (p *Program) GetResolvedTypeReferenceDirectiveFromTypeReferenceDirective(typeRef *ast.FileReference, sourceFile *ast.SourceFile) *module.ResolvedTypeReferenceDirective {
@@ -2208,7 +2203,7 @@ func (p *Program) collectPackageNames() *packageNamesInfo {
 }
 
 func (p *Program) IsLibFile(sourceFile *ast.SourceFile) bool {
-	_, ok := p.libFiles[sourceFile.Path()]
+	_, ok := p.libFilesByPath[sourceFile.Path()]
 	return ok
 }
Original file line number	Diff line number	Diff line change
`@@ -1710,7 +1710,7 @@ func (p *Program) GetDefaultResolutionModeForFile(sourceFile ast.HasFileName) co`
`1710`	`1710`	`}`
`1711`	`1711`
`1712`	`1712`	`func (p *Program) IsSourceFileDefaultLibrary(path tspath.Path) bool {`
`1713`		`- _, ok := p.libFiles[path]`
	`1713`	`+ _, ok := p.libFilesByPath[path]`
`1714`	`1714`	`return ok`
`1715`	`1715`	`}`
`1716`	`1716`
`@@ -1722,7 +1722,7 @@ func (p *Program) IsGlobalTypingsFile(fileName string) bool {`
`1722`	`1722`	`}`
`1723`	`1723`
`1724`	`1724`	`func (p Program) GetDefaultLibFile(path tspath.Path) LibFile {`
`1725`		`- if libFile, ok := p.libFiles[path]; ok {`
	`1725`	`+ if libFile, ok := p.libFilesByPath[path]; ok {`
`1726`	`1726`	`return libFile`
`1727`	`1727`	`}`
`1728`	`1728`	`return nil`
`@@ -2091,12 +2091,7 @@ func (p Program) GetLibFileFromReference(ref ast.FileReference) *ast.SourceFil`
`2091`	`2091`	`if !ok {`
`2092`	`2092`	`return nil`
`2093`	`2093`	`}`
`2094`		`- for path, libFile := range p.libFiles {`
`2095`		`- if libFile.Name == name {`
`2096`		`- return p.filesByPath[path]`
`2097`		`- }`
`2098`		`- }`
`2099`		`- return nil`
	`2094`	`+ return p.libFiles[name]`
`2100`	`2095`	`}`
`2101`	`2096`
`2102`	`2097`	`func (p Program) GetResolvedTypeReferenceDirectiveFromTypeReferenceDirective(typeRef ast.FileReference, sourceFile ast.SourceFile) module.ResolvedTypeReferenceDirective {`
`@@ -2208,7 +2203,7 @@ func (p Program) collectPackageNames() packageNamesInfo {`
`2208`	`2203`	`}`
`2209`	`2204`
`2210`	`2205`	`func (p Program) IsLibFile(sourceFile ast.SourceFile) bool {`
`2211`		`- _, ok := p.libFiles[sourceFile.Path()]`
	`2206`	`+ _, ok := p.libFilesByPath[sourceFile.Path()]`
`2212`	`2207`	`return ok`
`2213`	`2208`	`}`
`2214`	`2209`