clang/test/SemaCXX/vla.cpp

   1 // RUN: %clang_cc1 -triple x86_64-apple-macosx10.14.0 -verify -Wno-vla %s
   2
   3 // PR11925
   4 int n;
   5 int (&f())[n]; // expected-error {{function declaration cannot have variably modified type}}
   6
   7 namespace PR18581 {
   8   template<typename T> struct pod {};
   9   template<typename T> struct error {
  10     typename T::error e; // expected-error {{cannot be used prior to '::'}}
  11   };
  12   struct incomplete; // expected-note {{forward declaration}}
  13
  14   void f(int n) {
  15     pod<int> a[n];
  16     error<int> b[n]; // expected-note {{instantiation}}
  17     incomplete c[n]; // expected-error {{incomplete}}
  18   }
  19 }
  20
  21 void pr23151(int (&)[*]) { // expected-error {{variable length array must be bound in function definition}}
  22 }
  23
  24 void test_fold() {
  25   char a1[(unsigned long)(int *)0+1]{}; // expected-warning{{variable length array folded to constant array as an extension}}
  26   char a2[(unsigned long)(int *)0+1] = {}; // expected-warning{{variable length array folded to constant array as an extension}}
  27   char a3[(unsigned long)(int *)0+1];
  28 }
  29
  30 // Demonstrate that the check for a static_assert-like use of VLA does not
  31 // crash when there's no array size expression at all.
  32 void test_null_array_size_expr() {
  33   int array1[]; // expected-error {{definition of variable with array type needs an explicit size or an initializer}}
  34   int array2[] = { 1, 2, 3 };
  35 }
  36
  37 // Show that the check for a static_assert-like use of a VLA properly handles a
  38 // dependent array size expression.
  39 template <typename Ty>
  40 void func(int expr) {
  41   int array[sizeof(Ty) ? sizeof(Ty{}) : sizeof(int)];
  42   int old_style_assert[expr ? Ty::one : Ty::Neg_one]; // We don't diagnose as a VLA until instantiation
  43 }