diff --git a/parse/gram.y b/parse/gram.y
index 146c8422..7d953004 100644
--- a/parse/gram.y
+++ b/parse/gram.y
@@ -36,6 +36,7 @@ static void setattrs(Node *dcl, char **attrs, size_t nattrs);
 static void setwith(Type *ty, Traitspec **spec, size_t nspec);
 static void setupinit(Node *n);
 static void addinit(Node *blk, Node *dcl);
+static void setuname(Type *ty);

 %}

@@ -528,6 +529,7 @@ tydef       : Ttype typeid traitspec {$$ = $2;}
                        $$.type = mktyname($2.loc, mkname($2.loc, $2.name), $5);
                else
                        $$.type = mktygeneric($2.loc, mkname($2.loc, $2.name), $2.params, $2.nparams, $5);
+               setuname($$.type);
                setwith($$.type, $3.spec, $3.nspec);
        }
        ;
@@ -1147,6 +1149,17 @@ setupinit(Node *n)
        n->decl.name->name.name = strdup(s);
 }

+static void
+setuname(Type *ty)
+{
+       size_t i;
+
+       if (ty->sub[0]->type != Tyunion)
+               return;
+       for (i = 0; i < ty->sub[0]->nmemb; i++)
+               ty->sub[0]->udecls[i]->utype = ty;
+}
+
 static Node *
 mkpseudodecl(Srcloc l, Type *t)
 {
@@ -1231,7 +1244,8 @@ installucons(Stab *st, Type *t)
                break;
        case Tyunion:
                for (i = 0; i < b->nmemb; i++) {
-                       b->udecls[i]->utype = b;
+                       if (!b->udecls[i]->utype)
+                               b->udecls[i]->utype = b;
                        b->udecls[i]->id = i;
                        putucon(st, b->udecls[i]);
                }
diff --git a/parse/infer.c b/parse/infer.c
index c5cad2f1..42fc15c3 100644
--- a/parse/infer.c
+++ b/parse/infer.c
@@ -514,7 +514,7 @@ tyresolve(Type *t)
        case Tyunion:
                inaggr++;
                for (i = 0; i < t->nmemb; i++) {
-                       t->udecls[i]->utype = t;
+                       assert(t->udecls[i]->utype);
                        t->udecls[i]->utype = tf(t->udecls[i]->utype);
                        if (t->udecls[i]->etype) {
                                tyresolve(t->udecls[i]->etype);