clang/test/SemaCXX/recursive-lambda.cpp

   1 // RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify %s
   2
   3 // expected-no-diagnostics
   4
   5 // Check recursive instantiation of lambda does not cause assertion.
   6 // lambda function `f` in `fun1` is instantiated twice: first
   7 // as f(f, Number<1>), then as f(f, Number<0>). The
   8 // LocalInstantiationScopes of these two instantiations both contain
   9 // `f` and `i`. However, since they are not merged, clang should not
  10 // assert for that.
  11
  12 template <unsigned v>
  13 struct Number
  14 {
  15    static constexpr unsigned value = v;
  16 };
  17
  18 template <unsigned IBegin = 0,
  19           unsigned IEnd = 1>
  20 constexpr auto fun1(Number<IBegin> = Number<0>{}, Number<IEnd>  = Number<1>{})
  21 {
  22   constexpr unsigned a = 0;
  23   auto f = [&](auto fs, auto i) {
  24     if constexpr(i.value > 0)
  25     {
  26       (void)a;
  27       return fs(fs, Number<IBegin>{});
  28     }
  29     (void)a;
  30   };
  31
  32   return f(f, Number<IEnd>{});
  33 }
  34
  35
  36 void fun2() {
  37   fun1();
  38 }