diff --git a/CLI/FileUtils.cpp b/CLI/FileUtils.cpp
index cb993dfe..5e1e9047 100644
--- a/CLI/FileUtils.cpp
+++ b/CLI/FileUtils.cpp
@@ -190,7 +190,10 @@ bool traverseDirectory(const std::string& path, const std::function<void(const s
 bool isDirectory(const std::string& path)
 {
 #ifdef _WIN32
-    return (GetFileAttributesW(fromUtf8(path).c_str()) & FILE_ATTRIBUTE_DIRECTORY) != 0;
+    DWORD fileAttributes = GetFileAttributesW(fromUtf8(path).c_str());
+    if (fileAttributes == INVALID_FILE_ATTRIBUTES)
+        return false;
+    return (fileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 #else
     struct stat st = {};
     lstat(path.c_str(), &st);
@@ -244,8 +247,11 @@ std::vector<std::string> getSourceFiles(int argc, char** argv)
 
     for (int i = 1; i < argc; ++i)
     {
-        if (argv[i][0] == '-')
+        // Treat '-' as a special file whose source is read from stdin
+        // All other arguments that start with '-' are skipped
+        if (argv[i][0] == '-' && argv[i][1] != '\0') {
             continue;
+        }
 
         if (isDirectory(argv[i]))
         {