Hi!
Fairly non-problematic attribute, again on top of the whole series.
Tested on x86_64-linux, ok for trunk?
2024-09-05 Jakub Jelinek <ja...@redhat.com>
PR c++/110345
* g++.dg/cpp0x/attr-nodiscard1.C: New test.
--- gcc/testsuite/g++.dg/cpp0x/attr-nodiscard1.C.jj 2024-09-05
13:11:26.914049570 +0200
+++ gcc/testsuite/g++.dg/cpp0x/attr-nodiscard1.C 2024-09-05
13:38:05.456626161 +0200
@@ -0,0 +1,155 @@
+// C++ 26 P2552R3 - On the ignorability of standard attributes
+// { dg-do compile { target c++11 } }
+
+int arr[2];
+struct S { int a, b; };
+S arr2[2];
+
+void
+foo (int n)
+{
+ struct [[nodiscard]] S1 {};
+ struct [[nodiscard ("foobar")]] S2 {};
+ struct [[nodiscard (0)]] S3 {}; // { dg-error "'nodiscard'
attribute argument must be a string constant" }
+ struct [[nodiscard ("foo", "bar", "baz")]] S4 {}; // { dg-error "wrong
number of arguments specified for 'nodiscard' attribute" }
+ struct [[nodiscard (0, 1, 2)]] S5 {}; // { dg-error "wrong
number of arguments specified for 'nodiscard' attribute" }
+
+ auto a = [] [[nodiscard]] () {};
+ auto b = [] constexpr [[nodiscard]] {}; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ // { dg-error "parameter
declaration before lambda declaration specifiers only optional with" "" {
target c++20_down } .-1 }
+ // { dg-error "'constexpr'
lambda only available with" "" { target c++14_down } .-2 }
+ auto c = [] noexcept [[nodiscard]] {}; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ // { dg-error "parameter
declaration before lambda exception specification only optional with" "" {
target c++20_down } .-1 }
+ auto d = [] () [[nodiscard]] {}; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ auto e = new int [n] [[nodiscard]]; // { dg-warning "attributes
ignored on outermost array type in new expression" }
+ auto e2 = new int [n] [[nodiscard]] [42]; // { dg-warning "attributes
ignored on outermost array type in new expression" }
+ auto f = new int [n][42] [[nodiscard]]; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]]; // { dg-warning "attributes at
the beginning of statement are ignored" }
+ [[nodiscard]] {} // { dg-warning "attributes at
the beginning of statement are ignored" }
+ [[nodiscard]] if (true) {} // { dg-warning "attributes at
the beginning of statement are ignored" }
+ [[nodiscard]] while (false) {} // { dg-warning "attributes at
the beginning of statement are ignored" }
+ [[nodiscard]] goto lab; // { dg-warning "attributes at
the beginning of statement are ignored" }
+ [[nodiscard]] lab:; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]] try {} catch (int) {} // { dg-warning "attributes at
the beginning of statement are ignored" }
+ if ([[nodiscard]] int x = 0) {} // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ switch (n)
+ {
+ [[nodiscard]] case 1: // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]] break; // { dg-warning "attributes at
the beginning of statement are ignored" }
+ [[nodiscard]] default: // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ break;
+ }
+ for ([[nodiscard]] auto a : arr) {} // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ for ([[nodiscard]] auto [a, b] : arr2) {} // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ // { dg-error "structured
bindings only available with" "" { target c++14_down } .-1 }
+ [[nodiscard]] asm (""); // { dg-warning "attributes
ignored on 'asm' declaration" }
+ try {} catch ([[nodiscard]] int x) {} // { dg-warning
"'nodiscard' attribute can only be applied to functions or to class or
enumeration types" }
+ try {} catch ([[nodiscard]] int) {} // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ try {} catch (int [[nodiscard]] x) {} // { dg-warning
"attribute ignored" }
+ try {} catch (int [[nodiscard]]) {} // { dg-warning "attribute
ignored" }
+ try {} catch (int x [[nodiscard]]) {} // { dg-warning
"'nodiscard' attribute can only be applied to functions or to class or
enumeration types" }
+}
+
+[[nodiscard]] int bar ();
+using foobar [[nodiscard]] = int; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+[[nodiscard]] int a; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+[[nodiscard]] auto [b, c] = arr; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ // { dg-error "structured
bindings only available with" "" { target c++14_down } .-1 }
+[[nodiscard]]; // { dg-warning "attribute
ignored" }
+inline [[nodiscard]] void baz () {} // { dg-warning "attribute
ignored" }
+ // { dg-error "standard
attributes in middle of decl-specifiers" "" { target *-*-* } .-1 }
+constexpr [[nodiscard]] int qux () { return 0; } // { dg-warning
"attribute ignored" }
+ // { dg-error "standard
attributes in middle of decl-specifiers" "" { target *-*-* } .-1 }
+int [[nodiscard]] d; // { dg-warning "attribute
ignored" }
+int const [[nodiscard]] e = 1; // { dg-warning "attribute
ignored" }
+struct A {} [[nodiscard]]; // { dg-warning "attribute
ignored in declaration of 'struct A'" }
+struct A [[nodiscard]]; // { dg-warning
"attribute ignored" }
+struct A [[nodiscard]] a1; // { dg-warning "attribute
ignored" }
+A [[nodiscard]] a2; // { dg-warning "attribute
ignored" }
+enum B { B0 } [[nodiscard]]; // { dg-warning "attribute
ignored in declaration of 'enum B'" }
+enum B [[nodiscard]]; // { dg-warning "attribute
ignored" }
+enum B [[nodiscard]] b1; // { dg-warning "attribute
ignored" }
+B [[nodiscard]] b2; // { dg-warning "attribute
ignored" }
+struct [[nodiscard]] C {};
+int f [[nodiscard]]; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+int g[2] [[nodiscard]]; // { dg-warning
"'nodiscard' attribute can only be applied to functions or to class or
enumeration types" }
+int g2 [[nodiscard]] [2]; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+int corge () [[nodiscard]]; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+int *[[nodiscard]] h; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+int & [[nodiscard]] i = f; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+int && [[nodiscard]] j = 0; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+int S::* [[nodiscard]] k; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+auto l = sizeof (int [2] [[nodiscard]]); // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+int freddy ([[nodiscard]] int a, // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]] int, // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]] int c = 0, // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]] int = 0); // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+void
+corge ([[nodiscard]] int a, // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]] int, // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]] int c = 0, // { dg-warning
"'nodiscard' attribute can only be applied to functions or to class or
enumeration types" }
+ [[nodiscard]] int = 0) // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+{
+}
+[[nodiscard]] void
+garply () // { dg-warning "'nodiscard'
attribute applied to 'void garply\\\(\\\)' with void return type" }
+{
+}
+[[nodiscard]] int
+xyzzyy ()
+{
+ return 0;
+}
+int grault (int [[nodiscard]] a, // { dg-warning "attribute
ignored" }
+ int [[nodiscard]], // { dg-warning "attribute
ignored" }
+ int [[nodiscard]] c = 0, // { dg-warning "attribute
ignored" }
+ int [[nodiscard]] = 0); // { dg-warning "attribute
ignored" }
+void
+waldo (int [[nodiscard]] a, // { dg-warning "attribute
ignored" }
+ int [[nodiscard]], // { dg-warning "attribute
ignored" }
+ int [[nodiscard]] c = 0, // { dg-warning
"attribute ignored" }
+ int [[nodiscard]] = 0) // { dg-warning "attribute
ignored" }
+{
+}
+int plugh (int a [[nodiscard]], // { dg-warning
"'nodiscard' attribute can only be applied to functions or to class or
enumeration types" }
+ int b [[nodiscard]] = 0); // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+void
+thud (int a [[nodiscard]], // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ int b [[nodiscard]] = 0) // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+{
+}
+enum [[nodiscard]] D { D0 };
+enum class [[nodiscard]] E { E0 };
+enum F {};
+enum [[nodiscard]] F; // { dg-warning "type
attributes ignored after type is already defined" }
+enum G {
+ G0 [[nodiscard]], // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ G1 [[nodiscard]] = 2 // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+};
+namespace [[nodiscard]] H { using H0 = int; } // { dg-warning "'nodiscard'
attribute directive ignored" }
+namespace [[nodiscard]] {} // { dg-warning "'nodiscard'
attribute directive ignored" }
+[[nodiscard]] using namespace H; // { dg-warning "'nodiscard'
attribute directive ignored" }
+struct [[nodiscard]] I
+{
+ [[nodiscard]]; // { dg-error "declaration does
not declare anything" }
+ [[nodiscard]] int i; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]] int foo ();
+ [[nodiscard]] int bar () { return 1; }
+ [[nodiscard]] int : 0; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]] int i2 : 5; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ [[nodiscard]] static int i3; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+ static int i4;
+};
+[[nodiscard]] int I::i4 = 0; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+struct J : [[nodiscard]] C {}; // { dg-warning "attributes on
base specifiers are ignored" }
+#if __cpp_concepts >= 201907L
+template <typename T>
+concept K [[nodiscard]] = requires { true; }; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" ""
{ target c++20 } }
+#endif
+typedef int L [[nodiscard]]; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
+template <typename T>
+struct M {};
+template <>
+struct [[nodiscard]] M<int> { int m; };
+typedef int N[2] [[nodiscard]]; // { dg-warning
"'nodiscard' attribute can only be applied to functions or to class or
enumeration types" }
+typedef int O [[nodiscard]] [2]; // { dg-warning "'nodiscard'
attribute can only be applied to functions or to class or enumeration types" }
Jakub
