llvm-project/clang/test/CXX/temp/temp.param/p5.cpp

// RUN: %clang_cc1 -verify %s -std=c++14

template<const int I> struct S { // expected-error {{reference member 'r' binds to a temporary object}}
  decltype(I) n;
  int &&r = I; // expected-note {{default member initializer}}
};
S<5> s; // expected-note {{implicit default constructor}}

template<typename T, T v> struct U { // expected-error {{reference member 'r' binds to a temporary object}}
  decltype(v) n;
  int &&r = v; // expected-note {{default member initializer}}
};
U<const int, 6> u; // expected-note {{implicit default constructor}}
PR23135: Don't instantiate constexpr functions referenced in unevaluated operands where possible. This implements something like the current direction of DR1581: we use a narrow syntactic check to determine the set of places where a constant expression could be evaluated, and only instantiate a constexpr function or variable if it's referenced in one of those contexts, or is odr-used. It's not yet clear whether this is the right set of syntactic locations; we currently consider all contexts within templates that would result in odr-uses after instantiation, and contexts within list-initialization (narrowing conversions take another victim...), as requiring instantiation. We could in principle restrict the former cases more (only const integral / reference variable initializers, and contexts in which a constant expression is required, perhaps). However, this is sufficient to allow us to accept libstdc++ code, which relies on GCC's behavior (which appears to be somewhat similar to this approach). llvm-svn: 291318 2017-01-07 08:48:55 +08:00			`// RUN: %clang_cc1 -verify %s -std=c++14`
Implement [temp.param]p5: the top-level cv-qualifiers on a non-type template parameter's declaration are ignored when determining the parameter's type. llvm-svn: 152619 2012-03-13 15:21:50 +08:00
Fold -Wreturn-stack-address into general initialization lifetime checking. llvm-svn: 337743 2018-07-24 05:21:22 +08:00			`template<const int I> struct S { // expected-error {{reference member 'r' binds to a temporary object}}`
Implement [temp.param]p5: the top-level cv-qualifiers on a non-type template parameter's declaration are ignored when determining the parameter's type. llvm-svn: 152619 2012-03-13 15:21:50 +08:00			`decltype(I) n;`
Fold -Wreturn-stack-address into general initialization lifetime checking. llvm-svn: 337743 2018-07-24 05:21:22 +08:00			`int &&r = I; // expected-note {{default member initializer}}`
Implement [temp.param]p5: the top-level cv-qualifiers on a non-type template parameter's declaration are ignored when determining the parameter's type. llvm-svn: 152619 2012-03-13 15:21:50 +08:00			`};`
Restructure checking for, and warning on, lifetime extension. This change implements C++ DR1696, which makes initialization of a reference member of a class from a temporary object ill-formed. The standard wording here is imprecise, but we interpret it as meaning that any time a mem-initializer would result in lifetime extension, the program is ill-formed. This reinstates r337226, reverted in r337255, with a fix for the InitializedEntity alignment problem that was breaking ARM buildbots. llvm-svn: 337329 2018-07-18 06:24:09 +08:00			`S<5> s; // expected-note {{implicit default constructor}}`
Implement [temp.param]p5: the top-level cv-qualifiers on a non-type template parameter's declaration are ignored when determining the parameter's type. llvm-svn: 152619 2012-03-13 15:21:50 +08:00
Fold -Wreturn-stack-address into general initialization lifetime checking. llvm-svn: 337743 2018-07-24 05:21:22 +08:00			`template<typename T, T v> struct U { // expected-error {{reference member 'r' binds to a temporary object}}`
Implement [temp.param]p5: the top-level cv-qualifiers on a non-type template parameter's declaration are ignored when determining the parameter's type. llvm-svn: 152619 2012-03-13 15:21:50 +08:00			`decltype(v) n;`
Fold -Wreturn-stack-address into general initialization lifetime checking. llvm-svn: 337743 2018-07-24 05:21:22 +08:00			`int &&r = v; // expected-note {{default member initializer}}`
Implement [temp.param]p5: the top-level cv-qualifiers on a non-type template parameter's declaration are ignored when determining the parameter's type. llvm-svn: 152619 2012-03-13 15:21:50 +08:00			`};`
Restructure checking for, and warning on, lifetime extension. This change implements C++ DR1696, which makes initialization of a reference member of a class from a temporary object ill-formed. The standard wording here is imprecise, but we interpret it as meaning that any time a mem-initializer would result in lifetime extension, the program is ill-formed. This reinstates r337226, reverted in r337255, with a fix for the InitializedEntity alignment problem that was breaking ARM buildbots. llvm-svn: 337329 2018-07-18 06:24:09 +08:00			`U<const int, 6> u; // expected-note {{implicit default constructor}}`