llvm-project/clang/test/Parser/cuda-kernel-call.cu

// RUN: %clang_cc1 -fsyntax-only -verify %s

template<typename T=int> struct S {};
template<typename> void f();

void foo(void) {
  foo<<<1;      // expected-error {{expected '>>>'}} expected-note {{to match this '<<<'}}

  foo<<<1,1>>>; // expected-error {{expected '('}}

  foo<<<>>>();  // expected-error {{expected expression}}

  S<S<S<int>>> s;
  S<S<S<>>> s1;
  (void)(&f<S<S<int>>>==0);
  (void)(&f<S<S<>>>==0);
}