[Syntax] Mark synthesized nodes as modifiable

This was an oversight in the original patch.
Also add corresponding tests.

3 files changed, 24 insertions, 0 deletions

diff --git a/clang/include/clang/Tooling/Syntax/Tree.h b/clang/include/clang/Tooling/Syntax/Tree.h
index 640697a25f3..8702fe60ce1 100644
--- a/clang/include/clang/Tooling/Syntax/Tree.h
+++ b/clang/include/clang/Tooling/Syntax/Tree.h
@@ -123,6 +123,8 @@ private:
   friend class TreeBuilder;
   // MutationsImpl sets roles and CanModify flag.
   friend class MutationsImpl;
+  // FactoryImpl sets CanModify flag.
+  friend class FactoryImpl;
 
   Tree *Parent;
   Node *NextSibling;
diff --git a/clang/lib/Tooling/Syntax/Synthesis.cpp b/clang/lib/Tooling/Syntax/Synthesis.cpp
index cbd9579f4f0..aa01a34c761 100644
--- a/clang/lib/Tooling/Syntax/Synthesis.cpp
+++ b/clang/lib/Tooling/Syntax/Synthesis.cpp
@@ -13,6 +13,8 @@ using namespace clang;
 /// Should not be used for anything else.
 class syntax::FactoryImpl {
 public:
+  static void setCanModify(syntax::Node *N) { N->CanModify = true; }
+
   static void prependChildLowLevel(syntax::Tree *T, syntax::Node *Child,
                                    syntax::NodeRole R) {
     T->prependChildLowLevel(Child, R);
@@ -27,6 +29,7 @@ clang::syntax::Leaf *syntax::createPunctuation(clang::syntax::Arena &A,
   assert(Tokens.size() == 1);
   assert(Tokens.front().kind() == K);
   auto *L = new (A.allocator()) clang::syntax::Leaf(Tokens.begin());
+  FactoryImpl::setCanModify(L);
   L->assertInvariants();
   return L;
 }
@@ -34,6 +37,7 @@ clang::syntax::Leaf *syntax::createPunctuation(clang::syntax::Arena &A,
 clang::syntax::EmptyStatement *
 syntax::createEmptyStatement(clang::syntax::Arena &A) {
   auto *S = new (A.allocator()) clang::syntax::EmptyStatement;
+  FactoryImpl::setCanModify(S);
   FactoryImpl::prependChildLowLevel(S, createPunctuation(A, clang::tok::semi),
                                     NodeRole::Unknown);
   S->assertInvariants();
diff --git a/clang/unittests/Tooling/Syntax/TreeTest.cpp b/clang/unittests/Tooling/Syntax/TreeTest.cpp
index b54d06319e8..c457c788812 100644
--- a/clang/unittests/Tooling/Syntax/TreeTest.cpp
+++ b/clang/unittests/Tooling/Syntax/TreeTest.cpp
@@ -11,6 +11,7 @@
 #include "clang/AST/Decl.h"
 #include "clang/AST/Stmt.h"
 #include "clang/Basic/LLVM.h"
+#include "clang/Basic/TokenKinds.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendAction.h"
@@ -906,4 +907,21 @@ TEST_F(SyntaxTreeTest, Mutations) {
     CheckTransformation(C.first, C.second, RemoveStatement);
 }
 
+TEST_F(SyntaxTreeTest, SynthesizedNodes) {
+  buildTree("");
+
+  auto *C = syntax::createPunctuation(*Arena, tok::comma);
+  ASSERT_NE(C, nullptr);
+  EXPECT_EQ(C->token()->kind(), tok::comma);
+  EXPECT_TRUE(C->canModify());
+  EXPECT_FALSE(C->isOriginal());
+  EXPECT_TRUE(C->isDetached());
+
+  auto *S = syntax::createEmptyStatement(*Arena);
+  ASSERT_NE(S, nullptr);
+  EXPECT_TRUE(S->canModify());
+  EXPECT_FALSE(S->isOriginal());
+  EXPECT_TRUE(S->isDetached());
+}
+
 } // namespace