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1// RUN: %clang_cc1 -std=c2x -fsyntax-only -Wpre-c2x-compat -verify=compat %s2// RUN: %clang_cc1 -std=c17 -fsyntax-only -pedantic -Wno-comment -verify=pedantic %s3 4/* WG14 N2900: yes5 * Consistent, Warningless, and Intuitive Initialization with {}6 */7 8/* WG14 N3011: yes9 * Consistent, Warningless, and Intuitive Initialization with {}10 */11void test(void) {12 struct S { int x, y; } s = {}; // compat-warning {{use of an empty initializer is incompatible with C standards before C23}} \13 pedantic-warning {{use of an empty initializer is a C23 extension}}14 int i = {}; // compat-warning {{use of an empty initializer is incompatible with C standards before C23}} \15 pedantic-warning {{use of an empty initializer is a C23 extension}}16 int j = (int){}; // compat-warning {{use of an empty initializer is incompatible with C standards before C23}} \17 pedantic-warning {{use of an empty initializer is a C23 extension}}18 19 // C2x 6.7.10p4 says, in part: An array of unknown size shall not be20 // initialized by an empty initializer.21 // However, Clang allows zero-sized arrays as an extension in both C and C++,22 // and this initialization form will deduce the array extent as zero. Given23 // that we support empty initialization of an unbounded array in C++, we also24 // support it in C.25 int unknown_size[] = {}; // pedantic-warning {{zero size arrays are an extension}} \26 pedantic-warning {{use of an empty initializer is a C23 extension}} \27 compat-warning {{use of an empty initializer is incompatible with C standards before C23}}28 int vla[i] = {}; // compat-warning {{use of an empty initializer is incompatible with C standards before C23}} \29 pedantic-warning {{use of an empty initializer is a C23 extension}}30 // C99 6.5.2.5 Compound literals constraint 1: The type name shall specify an31 // object type or an array of unknown size, but not a variable length array32 // type.33 int *compound_literal_vla = (int[i]){}; // compat-warning {{use of an empty initializer is incompatible with C standards before C23}} \34 pedantic-warning {{use of an empty initializer is a C23 extension}}\35 compat-error {{compound literal cannot be of variable-length array type}} \36 pedantic-error {{compound literal cannot be of variable-length array type}}\37 38 39 struct T {40 int i;41 struct S s;42 } t1 = { 1, {} }; // compat-warning {{use of an empty initializer is incompatible with C standards before C23}} \43 pedantic-warning {{use of an empty initializer is a C23 extension}}44 45 struct T t2 = {46 1, {47 2, {} // compat-warning {{use of an empty initializer is incompatible with C standards before C23}} \48 pedantic-warning {{use of an empty initializer is a C23 extension}}49 }50 };51 52 struct T t3 = {53 (int){}, // compat-warning {{use of an empty initializer is incompatible with C standards before C23}} \54 pedantic-warning {{use of an empty initializer is a C23 extension}}55 {} // compat-warning {{use of an empty initializer is incompatible with C standards before C23}} \56 pedantic-warning {{use of an empty initializer is a C23 extension}}57 };58 59 // Ensure that zero initialization does what you'd expect in a constant expr.60 // FIXME: the "not an ICE" warning is incorrect for C2x, but we don't yet61 // implement WG14 N3038.62 _Static_assert((int){} == 0, "what?"); // compat-warning {{use of an empty initializer is incompatible with C standards before C23}} \63 pedantic-warning {{use of an empty initializer is a C23 extension}} \64 pedantic-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}65}66 67