llvm-project

9e1f1cfa - [Clang][Sema] Handle class member access expressions with valid nested-name-specifiers that become invalid after lookup (#98167)

[Clang][Sema] Handle class member access expressions with valid nested-name-specifiers that become invalid after lookup (#98167) The following code causes an assert in `SemaExprMember.cpp` on line 981 to fail: ``` struct A { }; struct B; void f(A *x) { x->B::y; // crash here } ``` This happens because we only return early from `BuildMemberReferenceExpr` when the `CXXScopeSpecifier` is invalid _before_ the lookup is performed. Since the lookup may invalidate the `CXXScopeSpecifier` (e.g. if the _nested-name-specifier_ is incomplete), this results in the second `BuildMemberReferenceExpr` overload being called with an invalid `CXXScopeSpecifier`, which causes the assert to fail. This patch moves the early return for invalid `CXXScopeSpecifiers` to occur _after_ lookup is performed. This fixes #92972. I also removed the `if (SS.isSet() && SS.isInvalid())` check in `ActOnMemberAccessExpr` because the condition can never be true (`isSet` returns `getScopeRep() != nullptr` and `isInvalid` returns `Range.isValid() && getScopeRep() == nullptr`).