diff --git a/internal/lsp/cache/cache.go b/internal/lsp/cache/cache.go
index c9fa616848..be6cd91695 100644
--- a/internal/lsp/cache/cache.go
+++ b/internal/lsp/cache/cache.go
@@ -236,6 +236,9 @@ func (c *Cache) PackageStats(withNames bool) template.HTML {
 }
 
 func astCost(f *ast.File) int64 {
+	if f == nil {
+		return 0
+	}
 	var count int64
 	ast.Inspect(f, func(n ast.Node) bool {
 		count += 32 // nodes are pretty small.