Adds test to prevent repeated variables in VALUES

Test for w3c/sparql-query#294

Author: Tpt

sparql/sparql12/manifest.ttl

@@ -40,4 +40,5 @@ trs:manifest  rdf:type mf:Manifest ;
     <expression/manifest.ttl>
     <lang-basedir/manifest.ttl>
     <rdf11/manifest.ttl>
+    <syntax/manifest.ttl>
   ) .

sparql/sparql12/syntax/duplicated-values-variable.rq

@@ -0,0 +1 @@
+SELECT * WHERE { VALUES (?a ?a) { (1 1) } }

sparql/sparql12/syntax/manifest.ttl

@@ -0,0 +1,17 @@
+@prefix rdf:    <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix :       <https://w3c.github.io/rdf-tests/sparql/sparql12/syntax/manifest#> .
+@prefix rdfs:   <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix mf:     <http://www.w3.org/2001/sw/DataAccess/tests/test-manifest#> .
+@prefix qt:     <http://www.w3.org/2001/sw/DataAccess/tests/test-query#> .
+@prefix dawgt:  <http://www.w3.org/2001/sw/DataAccess/tests/test-dawg#> .
+
+:manifest  rdf:type mf:Manifest ;
+    rdfs:label "Syntax" ;
+    mf:entries
+    (
+    :duplicated-values-variable
+    ) .
+
+:duplicated-values-variable rdf:type mf:NegativeSyntaxTest ;
+    mf:name "Duplicated variable in a VALUES clause" ;
+    mf:action <duplicated-values-variable.rq> .