clang/test/SemaCXX/enable_if-nested-call-with-valuedependent-param.cpp

   1 // RUN: %clang_cc1 -fsyntax-only %s -std=c++14
   2
   3 // Checks that Clang doesn't crash/assert on the nested call to "kaboom"
   4 // in "bar()".
   5 //
   6 // This is an interesting test case for `ExprConstant.cpp`'s `CallStackFrame`
   7 // because it triggers the following chain of events:
   8 // 0. `CheckEnableIf` calls `EvaluateWithSubstitution`.
   9 //  1. The outer call to "kaboom" gets evaluated.
  10 //   2. The expr for "a" gets evaluated, it has a version X;
  11 //      a temporary with the key (a, X) is created.
  12 //     3. The inner call to "kaboom" gets evaluated.
  13 //       4. The expr for "a" gets evaluated, it has a version Y;
  14 //          a temporary with the key (a, Y) is created.
  15 //       5. The expr for "b" gets evaluated, it has a version Y;
  16 //          a temporary with the key (b, Y) is created.
  17 //   6. `EvaluateWithSubstitution` looks at "b" but cannot evaluate it
  18 //      because it's value-dependent (due to the call to "f.foo()").
  19 //
  20 // When `EvaluateWithSubstitution` bails out while evaluating the outer
  21 // call, it attempts to fetch "b"'s param slot to clean it up.
  22 //
  23 // This used to cause an assertion failure in `getTemporary` because
  24 // a temporary with the key "(b, Y)" (created at step 4) existed but
  25 // not one for "(b, X)", which is what it was trying to fetch.
  26
  27 template<typename T>
  28 __attribute__((enable_if(true, "")))
  29 T kaboom(T a, T b) {
  30   return b;
  31 }
  32
  33 struct A {
  34   double foo();
  35 };
  36
  37 template <int>
  38 struct B {
  39   A &f;
  40
  41   void bar() {
  42     kaboom(kaboom(0.0, 1.0), f.foo());
  43   }
  44 };