Improve accuracy of detecting type trait fields.

tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.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.
 //
 // Changes Blink-style names to Chrome-style names. Currently transforms:
 //   fields:
 //     int m_operationCount => int operation_count_
 //   variables (including parameters):
 //     int mySuperVariable => int my_super_variable
 //   constants:
@@ skipping 75 matching lines @@
   if (Node.getNumDecls() == 0)
     return false;
 
   for (clang::NamedDecl* decl : Node.decls()) {
     if (!InnerMatcher.matches(*decl, Finder, Builder))
       return false;
   }
   return true;
 }
 
-bool IsDeclContextInWTF(const clang::DeclContext* decl_context) {
-  auto* namespace_decl = clang::dyn_cast_or_null<clang::NamespaceDecl>(
-      decl_context->getEnclosingNamespaceContext());
-  if (!namespace_decl)
-    return false;
-  if (namespace_decl->getParent()->isTranslationUnit() &&
-      namespace_decl->getName() == "WTF")
-    return true;
-  return IsDeclContextInWTF(namespace_decl->getParent());
-}
-
 template <typename T>
 bool MatchAllOverriddenMethods(
     const clang::CXXMethodDecl& decl,
     T&& inner_matcher,
     clang::ast_matchers::internal::ASTMatchFinder* finder,
     clang::ast_matchers::internal::BoundNodesTreeBuilder* builder) {
   bool override_matches = false;
   bool override_not_matches = false;
 
   for (auto it = decl.begin_overridden_methods();
@@ skipping 236 matching lines @@
   else if (original_name.startswith(kBlinkFieldPrefix))
     original_name = original_name.substr(strlen(kBlinkFieldPrefix));
 
   bool is_const = IsProbablyConst(decl, context);
   if (is_const) {
     // Don't try to rename constants that already conform to Chrome style.
     if (original_name.size() >= 2 && original_name[0] == 'k' &&
         clang::isUppercase(original_name[1]))
       return false;
 
-    // Struct consts in WTF do not become kFoo cuz stuff like type traits
-    // should stay as lowercase.
-    const clang::DeclContext* decl_context = decl.getDeclContext();
-    bool is_in_wtf = IsDeclContextInWTF(decl_context);
-    const clang::CXXRecordDecl* parent =
-        clang::dyn_cast_or_null<clang::CXXRecordDecl>(decl_context);
-    if (is_in_wtf && parent && parent->isStruct())
-      return false;
-
     name = 'k';
     name.append(original_name.data(), original_name.size());
     name[1] = clang::toUppercase(name[1]);
   } else {
     name = CamelCaseToUnderscoreCase(original_name);
 
     // Non-const variables with static storage duration at namespace scope are
     // prefixed with `g_' to reduce the likelihood of a naming collision.
     const clang::DeclContext* decl_context = decl.getDeclContext();
     if (name.find("g_") != 0 && decl.hasGlobalStorage() &&
@@ skipping 209 matching lines @@
 
   // Field, variable, and enum declarations ========
   // Given
   //   int x;
   //   struct S {
   //     int y;
   //     enum { VALUE };
   //   };
   // matches |x|, |y|, and |VALUE|.
   auto field_decl_matcher = id("decl", fieldDecl(in_blink_namespace));
-  auto var_decl_matcher = id("decl", varDecl(in_blink_namespace));
+  auto is_wtf_type_trait_value =
+      varDecl(hasName("value"), hasStaticStorageDuration(),
+              hasType(isConstQualified()), hasType(booleanType()),
+              hasAncestor(recordDecl(hasAncestor(namespaceDecl(
+                  hasName("WTF"), hasParent(translationUnitDecl()))))));
+  auto var_decl_matcher =
+      id("decl", varDecl(in_blink_namespace, unless(is_wtf_type_trait_value)));
   auto enum_member_decl_matcher =
       id("decl", enumConstantDecl(in_blink_namespace));
 
   FieldDeclRewriter field_decl_rewriter(&replacements);
   match_finder.addMatcher(field_decl_matcher, &field_decl_rewriter);
 
   VarDeclRewriter var_decl_rewriter(&replacements);
   match_finder.addMatcher(var_decl_matcher, &var_decl_rewriter);
 
   EnumConstantDeclRewriter enum_member_decl_rewriter(&replacements);
@@ skipping 267 matching lines @@
   for (const auto& r : replacements) {
     std::string replacement_text = r.getReplacementText().str();
     std::replace(replacement_text.begin(), replacement_text.end(), '\n', '\0');
     llvm::outs() << "r:::" << r.getFilePath() << ":::" << r.getOffset()
                  << ":::" << r.getLength() << ":::" << replacement_text << "\n";
   }
   llvm::outs() << "==== END EDITS ====\n";
 
   return 0;
 }