diff --git a/src/current/include/preproc/domain.xsl b/src/current/include/preproc/domain.xsl
index 435532e8..308bbb08 100644
--- a/src/current/include/preproc/domain.xsl
+++ b/src/current/include/preproc/domain.xsl
@@ -54,7 +54,6 @@
   "
   mode="preproc:mkdomain" priority="5">
 
-  <!-- generate all contained domains -->
   <variable name="subdomains">
     <variable name="union-types" select="
       lv:union/lv:typedef" />
@@ -70,7 +69,7 @@
     </if>
 
     <apply-templates mode="preproc:mkdomain"
-      select="$union-types" />
+                     select="$union-types" />
   </variable>
 
   <!-- provide a denormalized domain for performance and to reduce
@@ -80,7 +79,7 @@
     <with-param name="subdomains" select="$subdomains" />
   </call-template>
 
-  <copy-of select="$subdomains" />
+  <sequence select="$subdomains" />
 </template>
 
 
diff --git a/src/current/include/preproc/expand.xsl b/src/current/include/preproc/expand.xsl
index 2a1555d0..e337736f 100644
--- a/src/current/include/preproc/expand.xsl
+++ b/src/current/include/preproc/expand.xsl
@@ -85,10 +85,14 @@
 <!--
   Domain data are extracted from typedefs
 
-  Eventually, the typedefs will be converted into templates and removed entirely.
+  We must be sure that we (a) have not yet processed this typedef and (b)
+  that we do not handle nested typedefs (within unions), since that is done
+  for us by `preproc:mkdomain`.
 -->
-<template match="lv:typedef"
-  mode="preproc:expand" priority="5">
+<template match="lv:typedef[
+                   not( preceding-sibling::lv:domain/@name = @name )
+                   and not( ancestor::lv:union ) ]"
+          mode="preproc:expand" priority="5">
 
   <apply-templates select="." mode="preproc:mkdomain" />