diff --git a/src/rustc/middle/trans/alt.rs b/src/rustc/middle/trans/alt.rs
index d79fb51e804f80acd58df93abe21c0b598461158..5b0f620661c2f9d8d813c1d995b796b800046b16 100644
--- a/src/rustc/middle/trans/alt.rs
+++ b/src/rustc/middle/trans/alt.rs
@@ -164,7 +164,8 @@ fn enter_opt(tcx: ty::ctxt, m: match, opt: opt, col: uint,
         alt p.node {
           ast::pat_enum(_, subpats) {
             if opt_eq(tcx, variant_opt(tcx, p.id), opt) {
-              some(option::get_or_default(subpats, [])) }
+              some(option::get_or_default(subpats,
+                     vec::from_elem(variant_size, dummy))) }
             else { none }
           }
           ast::pat_ident(_, none) if pat_is_variant(tcx.def_map, p) {