[RecursiveASTVisitor] Fix RecursiveASTVisitor (RAV) fails to visit the initializer of a bitfield (#69557)

The problem was introduced in the commit
6b8e3c0
when the possibility of initialized bitfields was added, but the logic
in RecursiveASTVisitor was not updated. This PR fixed that.

This fixes #64916.

Patch by Scott McPeak

---------

Co-authored-by: cor3ntin <[email protected]>

Author: xgupta

clang/docs/ReleaseNotes.rst

@@ -650,6 +650,9 @@ Bug Fixes to AST Handling
   `Issue 64170 <https://github.com/llvm/llvm-project/issues/64170>`_
 - Fixed ``hasAnyBase`` not binding nodes in its submatcher.
   (`#65421 <https://github.com/llvm/llvm-project/issues/65421>`_)
+- Fixed a bug where RecursiveASTVisitor fails to visit the
+  initializer of a bitfield.
+  `Issue 64916 <https://github.com/llvm/llvm-project/issues/64916>`_
 
 Miscellaneous Bug Fixes
 ^^^^^^^^^^^^^^^^^^^^^^^

clang/include/clang/AST/RecursiveASTVisitor.h

@@ -2103,7 +2103,7 @@ DEF_TRAVERSE_DECL(FieldDecl, {
   TRY_TO(TraverseDeclaratorHelper(D));
   if (D->isBitField())
     TRY_TO(TraverseStmt(D->getBitWidth()));
-  else if (D->hasInClassInitializer())
+  if (D->hasInClassInitializer())
     TRY_TO(TraverseStmt(D->getInClassInitializer()));
 })
 

clang/unittests/Tooling/CMakeLists.txt

@@ -25,6 +25,7 @@ add_clang_unittest(ToolingTests
   QualTypeNamesTest.cpp
   RangeSelectorTest.cpp
   RecursiveASTVisitorTests/Attr.cpp
+  RecursiveASTVisitorTests/BitfieldInitializer.cpp
   RecursiveASTVisitorTests/CallbacksLeaf.cpp
   RecursiveASTVisitorTests/CallbacksUnaryOperator.cpp
   RecursiveASTVisitorTests/CallbacksBinaryOperator.cpp

clang/unittests/Tooling/RecursiveASTVisitorTests/BitfieldInitializer.cpp

@@ -0,0 +1,34 @@
+//===- unittest/Tooling/RecursiveASTVisitorTests/BitfieldInitializer.cpp -===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "TestVisitor.h"
+#include <string>
+
+using namespace clang;
+
+namespace {
+
+// Check to ensure that bitfield initializers are visited.
+class BitfieldInitializerVisitor
+    : public ExpectedLocationVisitor<BitfieldInitializerVisitor> {
+public:
+  bool VisitIntegerLiteral(IntegerLiteral *IL) {
+    Match(std::to_string(IL->getValue().getSExtValue()), IL->getLocation());
+    return true;
+  }
+};
+
+TEST(RecursiveASTVisitor, BitfieldInitializerIsVisited) {
+  BitfieldInitializerVisitor Visitor;
+  Visitor.ExpectMatch("123", 2, 15);
+  EXPECT_TRUE(Visitor.runOver("struct S {\n"
+                              "  int x : 8 = 123;\n"
+                              "};\n"));
+}
+
+} // end anonymous namespace