80 lines
2.3 KiB
C++
80 lines
2.3 KiB
C++
// RUN: %clang_cc1 -std=c++1z -verify %s
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void use_from_own_init() {
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auto [a] = a; // expected-error {{binding 'a' cannot appear in the initializer of its own decomposition declaration}}
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}
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// As a Clang extension, _Complex can be decomposed.
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float decompose_complex(_Complex float cf) {
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static _Complex float scf;
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auto &[sre, sim] = scf;
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// ok, this is references initialized by constant expressions all the way down
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static_assert(&sre == &__real scf);
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static_assert(&sim == &__imag scf);
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auto [re, im] = cf;
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return re*re + im*im;
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}
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// As a Clang extension, vector types can be decomposed.
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typedef float vf3 __attribute__((ext_vector_type(3)));
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float decompose_vector(vf3 v) {
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auto [x, y, z] = v;
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auto *p = &x; // expected-error {{address of vector element requested}}
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return x + y + z;
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}
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struct S { int a, b; };
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constexpr int f(S s) {
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auto &[a, b] = s;
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return a * 10 + b;
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}
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static_assert(f({1, 2}) == 12);
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constexpr bool g(S &&s) {
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auto &[a, b] = s;
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return &a == &s.a && &b == &s.b && &a != &b;
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}
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static_assert(g({1, 2}));
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void enclosing() {
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struct S { int a; };
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auto [n] = S(); // expected-note 2{{'n' declared here}}
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struct Q { int f() { return n; } }; // expected-error {{reference to local binding 'n' declared in enclosing function}}
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// FIXME: This is probably supposed to be valid, but we do not have clear rules on how it's supposed to work.
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(void) [&] { return n; }; // expected-error {{reference to local binding 'n' declared in enclosing function}}
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(void) [n] {}; // expected-error {{'n' in capture list does not name a variable}}
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}
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void bitfield() {
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struct { int a : 3, : 4, b : 5; } a;
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auto &[x, y] = a;
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auto &[p, q, r] = a; // expected-error {{decomposes into 2 elements, but 3 names were provided}}
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}
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void for_range() {
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int x = 1;
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for (auto[a, b] : x) { // expected-error {{invalid range expression of type 'int'; no viable 'begin' function available}}
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a++;
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}
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int y[5];
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for (auto[c] : y) { // expected-error {{cannot decompose non-class, non-array type 'int'}}
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c++;
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}
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}
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int error_recovery() {
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auto [foobar]; // expected-error {{requires an initializer}}
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return foobar_; // expected-error {{undeclared identifier 'foobar_'}}
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}
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// PR32172
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template <class T> void dependent_foreach(T t) {
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for (auto [a,b,c] : t)
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a,b,c;
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}
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// FIXME: by-value array copies
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