Improve accuracy of detecting type trait fields.

tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp

Index: tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp
diff --git a/tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp b/tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp
index 3a19515c190ac61352db73b703e20e33987e67ac..f073c73a713531066575133ae8729e850fc7bdfb 100644
--- a/tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp
+++ b/tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp
@@ -101,17 +101,6 @@ AST_MATCHER_P(clang::OverloadExpr,
   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,
@@ -453,13 +442,23 @@ bool GetNameForDecl(const clang::VarDecl& decl,
 
   bool is_const = IsProbablyConst(decl, context);
   if (is_const) {
-    // 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())
+    // Given
+    //   namespace WTF {
+    //     struct TypeTrait {
+    //       static const bool value = ...;
+    //     };
+    //   }
+    // matches |value|.
+    auto type_trait_matcher = varDecl(
+        hasName("value"),
+        hasStaticStorageDuration(),
+        hasType(isConstQualified()),
+        hasType(booleanType()),
+        hasAncestor(recordDecl(hasAncestor(namespaceDecl(
+            hasName("WTF"), hasParent(translationUnitDecl()))))));

[dcheng, 2016/08/24 21:42:17]

Since this is expressed as a matcher now, should we just move it into
field_decl_matcher?

[Łukasz Anforowicz, 2016/08/24 21:55:09]

Good point.  Done.  (although this has to go to |var_decl_matcher| - I think
static fields are varDecls, not fieldDecls (which I think only cover instance
fields?  I might be confused here...).

+
+    // Avoid renaming |value| -> |kValue| in WTF type traits.
+    if (!match(type_trait_matcher, decl, context).empty())
       return false;
 
     if (!GetNameForConstant(original_name.str(), name))