diff --git a/specifications/grammar-40/xpath-grammar.xml b/specifications/grammar-40/xpath-grammar.xml
index a44c2aa95..66dc4ca4b 100644
--- a/specifications/grammar-40/xpath-grammar.xml
+++ b/specifications/grammar-40/xpath-grammar.xml
@@ -1235,9 +1235,7 @@ VersionDecl ::= "xquery" (("encoding" StringLiteral) | ("version" StringLiteral
 
   <g:production name="SwitchExpr" if="xquery40">
     <g:string>switch</g:string>
-    <g:optional>
-      <g:ref name="SwitchComparand"/>
-    </g:optional>    
+    <g:ref name="SwitchComparand"/>
     <g:choice>
       <g:ref name="SwitchCases"/>
       <g:ref name="BracedSwitchCases"/>
@@ -1246,7 +1244,9 @@ VersionDecl ::= "xquery" (("encoding" StringLiteral) | ("version" StringLiteral
   
   <g:production name="SwitchComparand" if="xquery40">
     <g:string>(</g:string>
-    <g:ref name="Expr"/>
+    <g:optional>
+      <g:ref name="Expr"/>
+    </g:optional>
     <g:string>)</g:string>
   </g:production>
   
diff --git a/specifications/xquery-40/src/expressions.xml b/specifications/xquery-40/src/expressions.xml
index dd0bfe35e..0759d30f1 100644
--- a/specifications/xquery-40/src/expressions.xml
+++ b/specifications/xquery-40/src/expressions.xml
@@ -20925,7 +20925,7 @@ switch ($animal)
             <code>true</code>:</p>
          
          <eg role="parse-test" diff="add" at="issue671"><![CDATA[
-switch {
+switch () {
   case ($a le $b) return "lesser"
   case ($a ge $b) return "greater"
   case ($a eq $b) return "equal"