diff --git a/pkgs/development/tools/parsing/tree-sitter/grammar.nix b/pkgs/development/tools/parsing/tree-sitter/grammar.nix
index f92e0d79426..d9ad21dea61 100644
--- a/pkgs/development/tools/parsing/tree-sitter/grammar.nix
+++ b/pkgs/development/tools/parsing/tree-sitter/grammar.nix
@@ -30,7 +30,11 @@ stdenv.mkDerivation {
     if [ ! -f "$scanner_cc" ]; then
       scanner_cc=""
     fi
-    $CC -I$src/src/ -shared -o parser -Os $src/src/parser.c $scanner_cc -lstdc++
+    scanner_c="$src/src/scanner.c"
+    if [ ! -f "$scanner_c" ]; then
+      scanner_c=""
+    fi
+    $CC -I$src/src/ -shared -o parser -Os $src/src/parser.c $scanner_cc $scanner_c -lstdc++
     runHook postBuild
   '';
   installPhase = ''