Pseudo element selectors in compound selector lists are invalid.

third_party/WebKit/Source/core/css/parser/CSSSelectorParserTest.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/css/parser/CSSSelectorParser.h"
 
 #include "core/css/CSSSelectorList.h"
 #include "core/css/parser/CSSTokenizer.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 115 matching lines @@
 
     for (unsigned i = 0; i < WTF_ARRAY_LENGTH(testCases); ++i) {
         SCOPED_TRACE(testCases[i][0]);
         CSSTokenizer::Scope scope(testCases[i][0]);
         CSSParserTokenRange range = scope.tokenRange();
         CSSSelectorList list = CSSSelectorParser::parseSelector(range, CSSParserContext(HTMLStandardMode, nullptr), nullptr);
         EXPECT_STREQ(testCases[i][1], list.selectorsText().ascii().data());
     }
 }
 
+TEST(CSSSelectorParserTest, PseudoElementsInCompoundLists)
+{
+    const char* testCases[] = {
+        ":not(::before)",
+        ":not(::content)",
+        ":not(::shadow)",
+        ":host(::before)",
+        ":host(::content)",
+        ":host(::shadow)",
+        ":host-context(::before)",
+        ":host-context(::content)",
+        ":host-context(::shadow)",
+        ":-webkit-any(::after, ::before)",
+        ":-webkit-any(::content, span)",
+        ":-webkit-any(div, ::shadow)"
+    };
+
+    for (auto testCase : testCases) {
+        CSSTokenizer::Scope scope(testCase);
+        CSSParserTokenRange range = scope.tokenRange();
+        CSSSelectorList list = CSSSelectorParser::parseSelector(range, CSSParserContext(HTMLStandardMode, nullptr), nullptr);
+        EXPECT_FALSE(list.isValid());
+    }
+}
+
 } // namespace