1 // RUN: %clang_cc1 -verify=gnu -std=gnu++11 %s
2 // RUN: %clang_cc1 -verify=expected,cxx11 -Wvla -std=gnu++11 %s
3 // RUN: %clang_cc1 -verify=expected,cxx11 -std=c++11 %s
4 // RUN: %clang_cc1 -verify=expected,cxx98 -std=c++98 %s
5 // RUN: %clang_cc1 -verify=expected,off -std=c++11 -Wno-vla-extension-static-assert %s
6 // gnu-no-diagnostics
7
8 // Demonstrate that we do not diagnose use of VLAs by default in GNU mode, but
9 // we do diagnose them in C++ mode. Also note that we suggest use of
10 // static_assert, but only in C++11 and later and only if the warning group is
11 // not disabled.
12
13 // C++98 mode does not emit the same notes as C++11 mode because in C++98,
14 // we're looking for an integer constant expression, whereas in C++11 and later,
15 // we're looking for a constant expression that is of integer type (these are
16 // different operations; ICE looks at the syntactic form of the expression, but
17 // C++11 constant expressions require calculating the expression value).
func(int n)18 void func(int n) { // cxx11-note {{declared here}} off-note {{declared here}}
19 int vla[n]; // expected-warning {{variable length arrays in C++ are a Clang extension}} \
20 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}} \
21 off-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}
22 }
23
old_style_static_assert(int n)24 void old_style_static_assert(int n) { // cxx11-note 5 {{declared here}} off-note 2 {{declared here}}
25 int array1[n != 12 ? 1 : -1]; // cxx11-warning {{variable length arrays in C++ are a Clang extension; did you mean to use 'static_assert'?}} \
26 cxx98-warning {{variable length arrays in C++ are a Clang extension}} \
27 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}
28 int array2[n != 12 ? -1 : 1]; // cxx11-warning {{variable length arrays in C++ are a Clang extension; did you mean to use 'static_assert'?}} \
29 cxx98-warning {{variable length arrays in C++ are a Clang extension}} \
30 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}
31 int array3[n != 12 ? 1 : n]; // expected-warning {{variable length arrays in C++ are a Clang extension}} \
32 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}} \
33 off-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}
34 int array4[(n ? 1 : -1)]; // cxx11-warning {{variable length arrays in C++ are a Clang extension; did you mean to use 'static_assert'?}} \
35 cxx98-warning {{variable length arrays in C++ are a Clang extension}} \
36 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}
37 int array5[n ? 1 : 0]; // expected-warning {{variable length arrays in C++ are a Clang extension}} \
38 cxx11-note {{function parameter 'n' with unknown value cannot be used in a constant expression}} \
39 off-note {{function parameter 'n' with unknown value cannot be used in a constant expression}}
40 }
41