clang/test/Headers/crash-instantiated-in-scope-cxx-modules.cpp

   1 // RUN: rm -fR %t
   2 // RUN: split-file %s %t
   3 // RUN: cd %t
   4 // RUN: %clang_cc1 -std=c++20 -emit-header-unit -xc++-user-header -Werror=uninitialized folly-conv.h
   5 // RUN: %clang_cc1 -std=c++20 -emit-header-unit -xc++-user-header -Werror=uninitialized thrift_cpp2_base.h
   6 // RUN: %clang_cc1 -std=c++20 -emit-header-unit -xc++-user-header -Werror=uninitialized -fmodule-file=folly-conv.pcm -fmodule-file=thrift_cpp2_base.pcm logger_base.h
   7
   8 //--- Conv.h
   9 #pragma once
  10
  11 template <typename _Tp, typename _Up = _Tp&&>
  12 _Up __declval(int);
  13
  14 template <typename _Tp>
  15 auto declval() noexcept -> decltype(__declval<_Tp>(0));
  16
  17 namespace folly {
  18
  19 template <class Value, class Error>
  20 struct Expected {
  21   template <class Yes>
  22   auto thenOrThrow() -> decltype(declval<Value&>()) {
  23     return 1;
  24   }
  25 };
  26
  27 struct ExpectedHelper {
  28   template <class Error, class T>
  29   static constexpr Expected<T, Error> return_(T) {
  30     return Expected<T, Error>();
  31   }
  32
  33   template <class This, class Fn, class E = int, class T = ExpectedHelper>
  34   static auto then_(This&&, Fn&&)
  35       -> decltype(T::template return_<E>((declval<Fn>()(true), 0))) {
  36     return Expected<int, int>();
  37   }
  38 };
  39
  40 template <class Tgt>
  41 inline Expected<Tgt, const char*> tryTo() {
  42   Tgt result = 0;
  43   // In build with asserts:
  44   // clang/lib/Sema/SemaTemplateInstantiate.cpp: llvm::PointerUnion<Decl *, LocalInstantiationScope::DeclArgumentPack *> *clang::LocalInstantiationScope::findInstantiationOf(const Decl *): Assertion `isa<LabelDecl>(D) && "declaration not instantiated in this scope"' failed.
  45   // In release build compilation error on the line below inside lambda:
  46   // error: variable 'result' is uninitialized when used here [-Werror,-Wuninitialized]
  47   ExpectedHelper::then_(Expected<bool, int>(), [&](bool) { return result; });
  48   return {};
  49 }
  50
  51 } // namespace folly
  52
  53 inline void bar() {
  54   folly::tryTo<int>();
  55 }
  56 // expected-no-diagnostics
  57
  58 //--- folly-conv.h
  59 #pragma once
  60 #include "Conv.h"
  61 // expected-no-diagnostics
  62
  63 //--- thrift_cpp2_base.h
  64 #pragma once
  65 #include "Conv.h"
  66 // expected-no-diagnostics
  67
  68 //--- logger_base.h
  69 #pragma once
  70 import "folly-conv.h";
  71 import "thrift_cpp2_base.h";
  72
  73 inline void foo() {
  74   folly::tryTo<unsigned>();
  75 }
  76 // expected-no-diagnostics