eduucaldas added inline comments.
================ Comment at: clang/lib/Tooling/Syntax/Synthesis.cpp:237 + +syntax::Node *clang::syntax::deepCopy(syntax::Arena &A, const Node *N) { + if (!canModifyAllDescendants(N)) ---------------- We are ignoring nullability of pointers. The casting machinery asserts that on `dyn_cast` we don't have `nullptr`. So this code crashes on `nullptr`. From what I understand `dyn_cast` et al. are intended to be used on pointers. Are there other alternatives to this approach? I would like to encode the non-nullability in types instead of in asserts.... ================ Comment at: clang/lib/Tooling/Syntax/Synthesis.cpp:205 + if (L->canModify()) + syntax::FactoryImpl::setCanModify(Leaf); + ---------------- gribozavr2 wrote: > Since we are creating new leaves, why prohibit their mutation sometimes? > > I also don't quite understand the implications of having multiple leaves in a > tree that are backed by the same token. I think the algorithm that produces > edits can be confused by that. > > If you agree, please change the implementation to use `createLeaf` (or call > it directly from `deepCopy`). > Since we are creating new leaves, why prohibit their mutation sometimes? The `canModify` says whether the leaf is backed by a macro. Since the tokens coming from macros are expanded they would be expanded in the deepCopy as well. We agreed that this shouldn't be the default behaviour. We can have `deepCopyExpandingMacros`, if the user wants this behaviour, but I think `deepCopy` should simply forbid macros. WDYT about `deepCopyExpandingMacros`? > having multiple leaves in a tree that are backed by the same token We think the current algorithm wouldn't be confused by that. However it's easier to reason about `Leaf`s each with their `Token`, and we don't think creating additional `Leaf` nodes would affect performance largely. So we'll call `createLeaf` instead to create a fresh Leaf with the same Token as the previous one. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D87749/new/ https://reviews.llvm.org/D87749 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits