diff options
author | Richard Smith <richard-llvm@metafoo.co.uk> | 2018-09-26 04:36:55 +0000 |
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committer | Richard Smith <richard-llvm@metafoo.co.uk> | 2018-09-26 04:36:55 +0000 |
commit | 471124bcd92370793440cd7290e3adb1f8006227 (patch) | |
tree | 92cd22299f296997e1a21dd86e7ee0ff40db6667 /test/CXX | |
parent | ac26bee66c93b26678da8bfc09f3d738f23ba509 (diff) |
P0859R0: List-initialization is potentially-constant-evaluated and
triggers instantiation of constexpr functions.
We mostly implemented this since Clang 6, but missed the template
instantiation case.
We do not implement the '&cast-expression' special case. It appears to
be a mistake / oversight. I've mailed CWG to see if we can remove it.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@343064 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/CXX')
-rw-r--r-- | test/CXX/expr/expr.const/p6.cpp | 39 | ||||
-rw-r--r-- | test/CXX/temp/temp.spec/temp.inst/p7.cpp | 12 |
2 files changed, 51 insertions, 0 deletions
diff --git a/test/CXX/expr/expr.const/p6.cpp b/test/CXX/expr/expr.const/p6.cpp new file mode 100644 index 0000000000..a8fc7754e7 --- /dev/null +++ b/test/CXX/expr/expr.const/p6.cpp @@ -0,0 +1,39 @@ +// RUN: %clang_cc1 -std=c++17 -verify %s + +template<typename T> int not_constexpr() { return T::error; } +template<typename T> constexpr int is_constexpr() { return T::error; } // expected-error {{'::'}} + +template<typename T> int not_constexpr_var = T::error; +template<typename T> constexpr int is_constexpr_var = T::error; // expected-error {{'::'}} +template<typename T> const int is_const_var = T::error; // expected-error {{'::'}} +template<typename T> const volatile int is_const_volatile_var = T::error; +template<typename T> T is_dependent_var = T::error; // expected-error {{'::'}} +template<typename T> int &is_reference_var = T::error; // expected-error {{'::'}} +template<typename T> float is_float_var = T::error; + +void test() { + // Do not instantiate functions referenced in unevaluated operands... + (void)sizeof(not_constexpr<long>()); + (void)sizeof(is_constexpr<long>()); + (void)sizeof(not_constexpr_var<long>); + (void)sizeof(is_constexpr_var<long>); + (void)sizeof(is_const_var<long>); + (void)sizeof(is_const_volatile_var<long>); + (void)sizeof(is_dependent_var<long>); + (void)sizeof(is_dependent_var<const long>); + (void)sizeof(is_reference_var<long>); + (void)sizeof(is_float_var<long>); + + // ... but do if they are potentially constant evaluated, and refer to + // constexpr functions or to variables usable in constant expressions. + (void)sizeof(int{not_constexpr<int>()}); + (void)sizeof(int{is_constexpr<int>()}); // expected-note {{instantiation of}} + (void)sizeof(int{not_constexpr_var<int>}); + (void)sizeof(int{is_constexpr_var<int>}); // expected-note {{instantiation of}} + (void)sizeof(int{is_const_var<int>}); // expected-note {{instantiation of}} + (void)sizeof(int{is_const_volatile_var<int>}); + (void)sizeof(int{is_dependent_var<int>}); + (void)sizeof(int{is_dependent_var<const int>}); // expected-note {{instantiation of}} + (void)sizeof(int{is_reference_var<int>}); // expected-note {{instantiation of}} + (void)sizeof(int{is_float_var<int>}); // expected-error {{cannot be narrowed}} expected-note {{cast}} +} diff --git a/test/CXX/temp/temp.spec/temp.inst/p7.cpp b/test/CXX/temp/temp.spec/temp.inst/p7.cpp new file mode 100644 index 0000000000..5145dafdc5 --- /dev/null +++ b/test/CXX/temp/temp.spec/temp.inst/p7.cpp @@ -0,0 +1,12 @@ +// RUN: %clang_cc1 -verify -std=c++17 %s + +template<typename T> constexpr int f() { return T::value; } // expected-error {{'::'}} +template<bool B, typename T> void g(decltype(B ? f<T>() : 0)); +template<bool B, typename T> void g(...); +template<bool B, typename T> void h(decltype(int{B ? f<T>() : 0})); // expected-note {{instantiation of}} +template<bool B, typename T> void h(...); +void x() { + g<false, int>(0); // ok + g<true, int>(0); // ok + h<false, int>(0); // expected-note {{while substituting}} +} |