diff --git a/src/Compilation.zig b/src/Compilation.zig
index 2bb80a9abe816d4f609959a4e5d8e3ee0e35bde9..13fb6720420ae388ae4e26ef1b6475187cc05280 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -3941,6 +3941,7 @@ fn workerDocsWasmFallible(comp: *Compilation, prog_node: *std.Progress.Node) any
         .cc_argv = &.{},
         .parent = null,
         .builtin_mod = null,
+        .builtin_modules = null, // there is only one module in this compilation
     });
     const bin_basename = try std.zig.binNameAlloc(arena, .{
         .root_name = root_name,