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[NFC] Refactor [[nodiscard]] test to not use macros and run under -pedantic #95762

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Merged
merged 1 commit into from
Jun 17, 2024
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[NFC] Refactor [[nodiscard]] test to not use macros and run under -pedantic #95762

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62 changes: 27 additions & 35 deletions clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp
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Original file line number Diff line number Diff line change
@@ -1,16 +1,20 @@
// RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify -Wc++20-extensions %s
// RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify -Wc++17-extensions %s
// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify -DEXT -Wc++17-extensions -Wc++20-extensions %s
// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify=expected,cxx11,cxx11-17 -pedantic %s
// RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify=expected,cxx11-17,since-cxx17 -pedantic %s
// RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify=expected,since-cxx17 -pedantic %s

struct [[nodiscard]] S {};
// cxx11-warning@-1 {{use of the 'nodiscard' attribute is a C++17 extension}}
S get_s();
S& get_s_ref();

enum [[nodiscard]] E {};
// cxx11-warning@-1 {{use of the 'nodiscard' attribute is a C++17 extension}}
E get_e();

[[nodiscard]] int get_i();
// cxx11-warning@-1 {{use of the 'nodiscard' attribute is a C++17 extension}}
[[nodiscard]] volatile int &get_vi();
// cxx11-warning@-1 {{use of the 'nodiscard' attribute is a C++17 extension}}

void f() {
get_s(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
Expand All @@ -27,6 +31,7 @@ void f() {
}

[[nodiscard]] volatile char &(*fp)(); // expected-warning {{'nodiscard' attribute only applies to functions, classes, or enumerations}}
// cxx11-warning@-1 {{use of the 'nodiscard' attribute is a C++17 extension}}
void g() {
fp(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}

Expand Down Expand Up @@ -63,15 +68,20 @@ void f() {
} // namespace PR31526

struct [[nodiscard("reason")]] ReasonStruct {};
// cxx11-17-warning@-1 {{use of the 'nodiscard' attribute is a C++20 extension}}
struct LaterReason;
struct [[nodiscard("later reason")]] LaterReason {};
// cxx11-17-warning@-1 {{use of the 'nodiscard' attribute is a C++20 extension}}

ReasonStruct get_reason();
LaterReason get_later_reason();
[[nodiscard("another reason")]] int another_reason();
// cxx11-17-warning@-1 {{use of the 'nodiscard' attribute is a C++20 extension}}

[[nodiscard("conflicting reason")]] int conflicting_reason();
// cxx11-17-warning@-1 {{use of the 'nodiscard' attribute is a C++20 extension}}
[[nodiscard("special reason")]] int conflicting_reason();
// cxx11-17-warning@-1 {{use of the 'nodiscard' attribute is a C++20 extension}}

void cxx20_use() {
get_reason(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute: reason}}
Expand All @@ -82,17 +92,23 @@ void cxx20_use() {

namespace p1771 {
struct[[nodiscard("Don't throw me away!")]] ConvertTo{};
// cxx11-17-warning@-1 {{use of the 'nodiscard' attribute is a C++20 extension}}
struct S {
[[nodiscard]] S();
// cxx11-warning@-1 {{use of the 'nodiscard' attribute is a C++17 extension}}
[[nodiscard("Don't let that S-Char go!")]] S(char);
// cxx11-17-warning@-1 {{use of the 'nodiscard' attribute is a C++20 extension}}
S(int);
[[gnu::warn_unused_result]] S(double);
operator ConvertTo();
[[nodiscard]] operator int();
// cxx11-warning@-1 {{use of the 'nodiscard' attribute is a C++17 extension}}
[[nodiscard("Don't throw away as a double")]] operator double();
// cxx11-17-warning@-1 {{use of the 'nodiscard' attribute is a C++20 extension}}
};

struct[[nodiscard("Don't throw me away either!")]] Y{};
// cxx11-17-warning@-1 {{use of the 'nodiscard' attribute is a C++20 extension}}

void usage() {
S(); // expected-warning {{ignoring temporary created by a constructor declared with 'nodiscard' attribute}}
Expand All @@ -103,42 +119,18 @@ void usage() {
S s;
ConvertTo{}; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute: Don't throw me away!}}

// AST is different in C++20 mode, pre-2017 a move ctor for ConvertTo is there
// as well, hense the constructor warning.
#if __cplusplus >= 201703L
// expected-warning@+4 {{ignoring return value of function declared with 'nodiscard' attribute: Don't throw me away!}}
#else
// expected-warning@+2 {{ignoring temporary created by a constructor declared with 'nodiscard' attribute: Don't throw me away!}}
#endif
// AST is different in C++17 mode. Before, a move ctor for ConvertTo is there
// as well, hence the constructor warning.

// since-cxx17-warning@+2 {{ignoring return value of function declared with 'nodiscard' attribute: Don't throw me away!}}
// cxx11-warning@+1 {{ignoring temporary created by a constructor declared with 'nodiscard' attribute: Don't throw me away!}}
(ConvertTo) s;
(int)s; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
(S)'c'; // expected-warning {{ignoring temporary created by a constructor declared with 'nodiscard' attribute: Don't let that S-Char go!}}
#if __cplusplus >= 201703L
// expected-warning@+4 {{ignoring return value of function declared with 'nodiscard' attribute: Don't throw me away!}}
#else
// expected-warning@+2 {{ignoring temporary created by a constructor declared with 'nodiscard' attribute: Don't throw me away!}}
#endif
// since-cxx17-warning@+2 {{ignoring return value of function declared with 'nodiscard' attribute: Don't throw me away!}}
// cxx11-warning@+1 {{ignoring temporary created by a constructor declared with 'nodiscard' attribute: Don't throw me away!}}
static_cast<ConvertTo>(s);
static_cast<int>(s); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
static_cast<double>(s); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute: Don't throw away as a double}}
}
}; // namespace p1771

#ifdef EXT
// expected-warning@5 {{use of the 'nodiscard' attribute is a C++17 extension}}
// expected-warning@9 {{use of the 'nodiscard' attribute is a C++17 extension}}
// expected-warning@12 {{use of the 'nodiscard' attribute is a C++17 extension}}
// expected-warning@13 {{use of the 'nodiscard' attribute is a C++17 extension}}
// expected-warning@29 {{use of the 'nodiscard' attribute is a C++17 extension}}
// expected-warning@65 {{use of the 'nodiscard' attribute is a C++20 extension}}
// expected-warning@67 {{use of the 'nodiscard' attribute is a C++20 extension}}
// expected-warning@71 {{use of the 'nodiscard' attribute is a C++20 extension}}
// expected-warning@73 {{use of the 'nodiscard' attribute is a C++20 extension}}
// expected-warning@74 {{use of the 'nodiscard' attribute is a C++20 extension}}
// expected-warning@84 {{use of the 'nodiscard' attribute is a C++20 extension}}
// expected-warning@86 {{use of the 'nodiscard' attribute is a C++17 extension}}
// expected-warning@87 {{use of the 'nodiscard' attribute is a C++20 extension}}
// expected-warning@91 {{use of the 'nodiscard' attribute is a C++17 extension}}
// expected-warning@92 {{use of the 'nodiscard' attribute is a C++20 extension}}
// expected-warning@95 {{use of the 'nodiscard' attribute is a C++20 extension}}
#endif
} // namespace p1771
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