50f0b30cff
No release note for this one because the one added by #129737 already mentions ‘non-variable declarations’. Fixes #56471.
75 lines
3.4 KiB
C
75 lines
3.4 KiB
C
// RUN: %clang_cc1 -verify -Wgnu-folding-constant %s
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/* WG14 N1330: Yes
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* Static assertions
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*/
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// Test syntactic requirements: first argument must be a constant expression,
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// and the second argument must be a string literal. We support the C2x
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// extension that allows you to elide the second argument.
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int a;
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_Static_assert(a, ""); // expected-error {{static assertion expression is not an integral constant expression}}
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_Static_assert(1); // expected-warning {{'_Static_assert' with no message is a C23 extension}}
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// Test functional requirements
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_Static_assert(1, "this works");
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_Static_assert(0, "this fails"); // expected-error {{static assertion failed: this fails}}
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_Static_assert(0); // expected-error {{static assertion failed}} \
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expected-warning {{'_Static_assert' with no message is a C23 extension}}
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// Test declaration contexts. We've already demonstrated that file scope works.
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struct S {
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_Static_assert(1, "this works");
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union U {
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long l;
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_Static_assert(1, "this works");
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} u;
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enum E {
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_Static_assert(1, "this should not compile"); // expected-error {{expected identifier}}
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One
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} e;
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};
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void func( // expected-note {{to match this '('}}
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_Static_assert(1, "this should not compile") // expected-error {{expected parameter declarator}} \
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expected-error {{expected ')'}}
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);
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void func( // expected-note {{to match this '('}}
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_Static_assert(1, "this should not compile") // expected-error {{expected parameter declarator}} \
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expected-error {{expected ')'}}
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) {}
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void test(void) {
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_Static_assert(1, "this works");
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_Static_assert(0, "this fails"); // expected-error {{static assertion failed: this fails}}
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// While the use of a _Static_assert in a for loop declaration is prohibited per
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// 6.8.5p3 (requiring the declaration to only declare identifiers for objects
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// having auto or register storage class; a static assertion does not declare
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// an identifier nor an object), we permit it as an extension.
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int i = 0;
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for (_Static_assert(1, "this should compile"); i < 10; ++i)
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;
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// Ensure that only an integer constant expression can be used as the
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// controlling expression.
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_Static_assert(1.0f, "this should not compile"); // expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}
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}
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#if __STDC_VERSION__ < 202311L
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// The use of a _Static_assert in a K&R C function definition is prohibited per
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// 6.9.1p6 requiring each declaration to have a declarator (which a static
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// assertion does not have) and only declare identifiers from the identifier
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// list.
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// The error about expecting a ';' is due to the static assertion confusing the
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// compiler. It'd be nice if we improved the diagnostics here, but because this
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// involves a K&R C declaration, it's low priority.
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void knr(a, b, c) // expected-warning {{a function definition without a prototype is deprecated in all versions of C and is not supported in C23}}
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int a, b; // expected-error {{expected ';' at end of declaration}}
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_Static_assert(1, "this should not compile"); // expected-error {{expected identifier or '('}} \
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expected-error {{type specifier missing, defaults to 'int'; ISO C99 and later do not support implicit int}}
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float c;
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{
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}
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#endif // __STDC_VERSION__
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