diff --git a/src/Lexer.php b/src/Lexer.php
index 16068b1b3..d507d9a54 100644
--- a/src/Lexer.php
+++ b/src/Lexer.php
@@ -466,16 +466,15 @@ class Lexer
         $regex = [];
         foreach ($operators as $operator => $length) {
             // an operator that ends with a character must be followed by
-            // a whitespace or a parenthesis
+            // a whitespace, a parenthesis, an opening map [ or sequence {
             $r = preg_quote($operator, '/');
             if (ctype_alpha($operator[$length - 1])) {
-                $r .= '(?=[\s()])';
+                $r .= '(?=[\s()\[{])';
             }
 
-            // an operator that begins with a character must have a space before
-            // or a parenthesis
+            // an operator that begins with a character must not have a dot or pipe before
             if (ctype_alpha($operator[0])) {
-                $r = '(?<=[\s(])'.$r;
+                $r = '(?<![\.\|])'.$r;
             }
 
             // an operator with a space can be any amount of whitespaces
diff --git a/tests/Fixtures/expressions/not.test b/tests/Fixtures/expressions/not.test
index 40914a3e1..3c15a21b4 100644
--- a/tests/Fixtures/expressions/not.test
+++ b/tests/Fixtures/expressions/not.test
@@ -3,8 +3,12 @@ not
 --TEMPLATE--
 {{ (not false) ? 'OK' : 'KO' }}
 {{ not false ? 'OK' : 'KO' }}
+{{ (not false)?'OK':'KO' }}
+{{ not false?'OK':'KO' }}
 --DATA--
 return []
 --EXPECT--
 OK
 OK
+OK
+OK
diff --git a/tests/Fixtures/tests/in.test b/tests/Fixtures/tests/in.test
index 20c3d947b..bca4468ee 100644
--- a/tests/Fixtures/tests/in.test
+++ b/tests/Fixtures/tests/in.test
@@ -61,6 +61,7 @@ Twig supports the in operator
 {{ 'value'|not in ['not value'] ? 'OK' : 'KO' }}
 {{ foo.not not in ['not'] ? 'KO' : 'OK' }}
 {{ 'value'|not not in ['not value'] ? 'KO' : 'OK' }}
+{{ 'value'not in['not value'] ? 'OK' : 'KO' }}
 --DATA--
 return ['bar' => 'bar', 'foo' => ['bar' => 'bar', 'not' => 'not'], 'dir_object' => new \SplFileInfo(__DIR__), 'object' => new \stdClass(), 'resource' => opendir(__DIR__), 'safe' => new \Twig\Markup('foo', 'UTF-8')]
 --EXPECT--
@@ -124,3 +125,4 @@ OK
 OK
 OK
 OK
+OK