added a deprecation notice when using the spaceless tag

src/TokenParser/SpacelessTokenParser.php

@@ -30,6 +30,8 @@ final class SpacelessTokenParser extends AbstractTokenParser
 {
     public function parse(Token $token)
     {
+        @trigger_error('The spaceless tag is deprecated since version 2.7, use the spaceless filter instead.', E_USER_DEPRECATED);
+
         $lineno = $token->getLine();
 
         $this->parser->getStream()->expect(/* Token::BLOCK_END_TYPE */ 3);

test/Twig/Tests/Fixtures/tags/block/capturing_block.test

@@ -1,5 +1,7 @@
 --TEST--
 capturing "block" tag
+--DEPRECATION--
+The spaceless tag is deprecated since version 2.7, use the spaceless filter instead.
 --TEMPLATE--
 {% set foo %}{% block foo %}FOO{% endblock %}{% endset %}
 {{ foo }}

test/Twig/Tests/Fixtures/tags/spaceless/root_level_in_child.legacy.test

@@ -1,6 +1,7 @@
 --TEST--
 "spaceless" tag in the root level of a child template
 --DEPRECATION--
+The spaceless tag is deprecated since version 2.7, use the spaceless filter instead.
 Using the spaceless tag at the root level of a child template in "index.twig" at line 3 is deprecated since Twig 2.5.0 and will become a syntax error in 3.0.
 Nesting a block definition under a non-capturing node in "index.twig" at line 4 is deprecated since Twig 2.5.0 and will become a syntax error in 3.0.
 --TEMPLATE--

test/Twig/Tests/Fixtures/tags/spaceless/simple.test

@@ -1,5 +1,7 @@
 --TEST--
 "spaceless" tag removes whites between HTML tags
+--DEPRECATION--
+The spaceless tag is deprecated since version 2.7, use the spaceless filter instead.
 --TEMPLATE--
 {% spaceless %}