[all-commits] [llvm/llvm-project] b84fd8: Add boundary check for ASTUnresolvedSet::erase

[Zhouyi Zhou via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b84fd822fa7eeaec2bb084a26caa9e41f3495923
      https://github.com/llvm/llvm-project/commit/b84fd822fa7eeaec2bb084a26caa9e41f3495923
  Author: Zhouyi Zhou <zhouzhouyi at gmail.com>
  Date:   2022-11-06 (Sun, 06 Nov 2022)

  Changed paths:
    M clang/include/clang/AST/ASTUnresolvedSet.h
    M clang/test/SemaCXX/using-decl-templates.cpp

  Log Message:
  -----------
  Add boundary check for ASTUnresolvedSet::erase

When compile following code with clang (Debug build), Assertion will be triggered.

```
struct A
{
        struct Nested {};
        operator Nested*() {return 0;};
};

struct B : A
{
        using A::operator typename A::Nested*;
        operator typename A::Nested *() {
                struct A * thi = this;
                return *thi;
        };
};
```

The assertion fail is caused by: `void erase(unsigned I) { Decls[I] = Decls.pop_back_val(); }` when size of `Decls` is 1 before erase.

Reviewed By: rjmccall, MaskRay

Differential Revision: https://reviews.llvm.org/D137263