diff --git a/src/builtin_source.cpp b/src/builtin_source.cpp
index 655111e92..1e09b702e 100644
--- a/src/builtin_source.cpp
+++ b/src/builtin_source.cpp
@@ -41,7 +41,7 @@ int builtin_source(parser_t &parser, io_streams_t &streams, wchar_t **argv) {
 
     if (argc == optind || wcscmp(argv[optind], L"-") == 0) {
         // Either a bare `source` which means to implicitly read from stdin or an explicit `-`.
-        if (argc == optind && !streams.stdin_is_directly_redirected) {
+        if (argc == optind && isatty(streams.stdin_fd)) {
             // Don't implicitly read from the terminal.
             return STATUS_CMD_ERROR;
         }
diff --git a/tests/test1.in b/tests/test1.in
index e747f3143..104f984ea 100644
--- a/tests/test1.in
+++ b/tests/test1.in
@@ -214,7 +214,7 @@ echo 'echo "source argv {$argv}"' | source -
 echo 'echo "source argv {$argv}"' | source - abc
 echo 'echo "source argv {$argv}"' | source - abc def
 # This hangs if it fails!
-source
+source </dev/tty
 echo $status
 
 always_fails