[PATCH] D147626: [clang] Do not crash when initializing union with flexible array member

[Mariya Podchishchaeva via Phabricator via cfe-commits]

Fznamznon added inline comments.


================
Comment at: clang/lib/Sema/SemaInit.cpp:808
       unsigned NumElems = numStructUnionElements(ILE->getType());
-      if (RDecl->hasFlexibleArrayMember())
+      if (!RDecl->isUnion() && RDecl->hasFlexibleArrayMember())
         ++NumElems;
----------------
Just for some context, numStructUnionElements checks that there is a flexible array member and returns number_of_initializable_fields-1 for structs. For unions it just returns 1 or 0, so flexible array member caused adding one more element to initlistexpr that was never properly handled.

Instead of doing this change, we could probably never enter initialization since the record (union) declaration is not valid, but that is not the case even for other types of errors in code, for example, I've tried declaring field of struct with a typo:

```
struct { cha x[]; } r = {1}; 
```
Initialization is still performed by clang.
Also, it seems MSVC considers flexible array member inside union as valid, so the test code is probably not always invalid.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D147626/new/

https://reviews.llvm.org/D147626