libcxx/test/std/utilities/format/format.functions/format.verify.cpp

   1 //===----------------------------------------------------------------------===//
   2 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   3 // See https://llvm.org/LICENSE.txt for license information.
   4 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   5 //
   6 //===----------------------------------------------------------------------===//
   7
   8 // UNSUPPORTED: c++03, c++11, c++14, c++17
   9
  10 // TODO FMT This test should not require std::to_chars(floating-point)
  11 // XFAIL: availability-fp_to_chars-missing
  12
  13 // Basic test to validate ill-formed code is properly detected.
  14
  15 // <format>
  16
  17 // template<class... Args>
  18 //   string format(format-string<Args...> fmt, const Args&... args);
  19 // template<class... Args>
  20 //   wstring format(wformat-string<Args...> fmt, const Args&... args);
  21
  22 #include <format>
  23
  24 #include "test_macros.h"
  25
  26 // clang-format off
  27
  28 void f() {
  29   TEST_IGNORE_NODISCARD std::format("{"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  30   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  31
  32   TEST_IGNORE_NODISCARD std::format("}"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  33   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  34
  35   TEST_IGNORE_NODISCARD std::format("{}"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  36   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  37
  38   TEST_IGNORE_NODISCARD std::format("{0}"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  39   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  40
  41   TEST_IGNORE_NODISCARD std::format("{:-}", "Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  42   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  43
  44   TEST_IGNORE_NODISCARD std::format("{:#}", "Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  45   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  46
  47   TEST_IGNORE_NODISCARD std::format("{:L}", "Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  48   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  49
  50   TEST_IGNORE_NODISCARD std::format("{0:{0}}", "Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  51   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  52
  53   TEST_IGNORE_NODISCARD std::format("{:.42d}", "Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  54   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  55
  56   TEST_IGNORE_NODISCARD std::format("{:d}", "Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  57   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  58
  59 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  60   TEST_IGNORE_NODISCARD std::format(L"{"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  61   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  62
  63   TEST_IGNORE_NODISCARD std::format(L"}"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  64   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  65
  66   TEST_IGNORE_NODISCARD std::format(L"{}"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  67   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  68
  69   TEST_IGNORE_NODISCARD std::format(L"{0}"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  70   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  71
  72   TEST_IGNORE_NODISCARD std::format(L"{:-}", L"Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  73   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  74
  75   TEST_IGNORE_NODISCARD std::format(L"{:#}", L"Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  76   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  77
  78   TEST_IGNORE_NODISCARD std::format(L"{:L}", L"Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  79   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  80
  81   TEST_IGNORE_NODISCARD std::format(L"{0:{0}}", L"Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  82   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  83
  84   TEST_IGNORE_NODISCARD std::format(L"{:.42d}", L"Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  85   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  86
  87   TEST_IGNORE_NODISCARD std::format(L"{:d}", L"Forty-two"); // expected-error-re{{call to consteval function '{{.*}}' is not a constant expression}}
  88   // expected-note@*:* {{non-constexpr function '__throw_format_error' cannot be used in a constant expression}}
  89 #endif
  90 }
  91
  92 struct tiny {
  93   int bit : 1;
  94 };
  95
  96 void P2418()
  97 {
  98   auto t = tiny{};
  99   TEST_IGNORE_NODISCARD std::format("{}", t.bit); // expected-error{{non-const reference cannot bind to bit-field 'bit'}}
 100
 101 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
 102   TEST_IGNORE_NODISCARD std::format(L"{}", t.bit); // expected-error{{non-const reference cannot bind to bit-field 'bit'}}
 103 #endif
 104 }