Let RecursiveASTVisitor visit array index VarDecls

[thakis]

Summary

An implicit copy ctor creates loop VarDecls that hang off CXXCtorInitializer. RecursiveASTVisitor used to not visit them, so that they didn't show up in the parent map used by ASTMatchers, causing asserts() when the implicit DeclRefExpr() in a CXXCtorInitializer referred to one of these VarDecls.

Fixes PR26227.

[thakis]

fix test name

[klimek]

LG.
I'd probably add a test to unittests/Tooling/RecursiveASTVisitorTest.cpp.

[thakis]

r258503, thanks! (with the extra test)

include/clang/AST/RecursiveASTVisitor.h

 template <typename Derived>
 bool RecursiveASTVisitor<Derived>::TraverseConstructorInitializer(
     CXXCtorInitializer *Init) {
   if (TypeSourceInfo *TInfo = Init->getTypeSourceInfo())
     TRY_TO(TraverseTypeLoc(TInfo->getTypeLoc()));
 
   if (Init->isWritten() || getDerived().shouldVisitImplicitCode())
     TRY_TO(TraverseStmt(Init->getInit()));
+
+  if (Init->getNumArrayIndices() && getDerived().shouldVisitImplicitCode())
+    for (VarDecl *VD : Init->getArrayIndexes())
+      TRY_TO(TraverseDecl(VD));
   return true;
 }
 
 template <typename Derived>
 bool
 RecursiveASTVisitor<Derived>::TraverseLambdaCapture(LambdaExpr *LE,
                                                     const LambdaCapture *C) {
   if (LE->isInitCapture(C))

unittests/ASTMatchers/ASTMatchersTest.cpp

EXPECT_TRUE(matches(
       "void t() { C<int>::f(); }",
       integerLiteral(
           equals(42),
           allOf(
               hasAncestor(cxxRecordDecl(isTemplateInstantiation())),
               hasAncestor(cxxRecordDecl(unless(isTemplateInstantiation())))))));
 }
 
+TEST(HasAncestor, ImplicitArrayCopyCtorDeclRefExpr) {
+  EXPECT_TRUE(matches("struct MyClass {\n"
+                      "  int c[1];\n"
+                      "  static MyClass Create() { return MyClass(); }\n"
+                      "};",
+                      declRefExpr(to(decl(hasAncestor(decl()))))));
+}
+
 TEST(HasParent, MatchesAllParents) {
   EXPECT_TRUE(matches(
       "template <typename T> struct C { static void f() { 42; } };"
       "void t() { C<int>::f(); }",
       integerLiteral(
           equals(42),
           hasParent(compoundStmt(hasParent(functionDecl(
               hasParent(cxxRecordDecl(isTemplateInstantiation())))))))));