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author | Carlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au> | 2012-10-15 17:10:06 +1100 |
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committer | Carlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au> | 2012-10-15 17:10:06 +1100 |
commit | be1de4be954c80875ad4108e0a33e8e131b2f2c0 (patch) | |
tree | 1fbbecf276bf7c7bdcbb4dd446099d6d90eaa516 /clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp | |
parent | c4626a62754862d20b41e8a46a3574264ea80e6d (diff) | |
parent | f1bd2e48c5324d3f7cda4090c87f8a5b6f463ce2 (diff) |
Merge branch 'master' of ssh://bitbucket.org/czan/honours
Diffstat (limited to 'clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp')
-rw-r--r-- | clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp b/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp new file mode 100644 index 0000000..cafdd63 --- /dev/null +++ b/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp @@ -0,0 +1,139 @@ +// RUN: %clang_cc1 -verify -std=c++11 %s + +namespace N { + typedef char C; +} + +namespace M { + typedef double D; +} + +struct NonLiteral { // expected-note 2{{no constexpr constructors}} + NonLiteral() {} + NonLiteral(int) {} +}; +struct Literal { + constexpr Literal() {} + operator int() const { return 0; } +}; + +struct S { + virtual int ImplicitlyVirtual() const = 0; // expected-note {{overridden virtual function}} +}; +struct SS : S { + int ImplicitlyVirtual() const; +}; + +// The definition of a constexpr function shall satisfy the following +// constraints: +struct T : SS, NonLiteral { // expected-note {{base class 'NonLiteral' of non-literal type}} + constexpr T(); + constexpr int f(); // expected-error {{non-literal type 'T' cannot have constexpr members}} + + // - it shall not be virtual; + virtual constexpr int ExplicitlyVirtual() { return 0; } // expected-error {{virtual function cannot be constexpr}} + + constexpr int ImplicitlyVirtual() { return 0; } // expected-error {{virtual function cannot be constexpr}} + + // - its return type shall be a literal type; + constexpr NonLiteral NonLiteralReturn() { return {}; } // expected-error {{constexpr function's return type 'NonLiteral' is not a literal type}} + constexpr void VoidReturn() { return; } // expected-error {{constexpr function's return type 'void' is not a literal type}} + constexpr ~T(); // expected-error {{destructor cannot be marked constexpr}} + typedef NonLiteral F(); + constexpr F NonLiteralReturn2; // ok until definition + + // - each of its parameter types shall be a literal type; + constexpr int NonLiteralParam(NonLiteral) { return 0; } // expected-error {{constexpr function's 1st parameter type 'NonLiteral' is not a literal type}} + typedef int G(NonLiteral); + constexpr G NonLiteralParam2; // ok until definition + + // - its function-body shall be = delete, = default, + constexpr int Deleted() = delete; + // It's not possible for the function-body to legally be "= default" here. + // Other than constructors, only the copy- and move-assignment operators and + // destructor can be defaulted. Destructors can't be constexpr since they + // don't have a literal return type. Defaulted assignment operators can't be + // constexpr since they can't be const. + constexpr T &operator=(const T&) = default; // expected-error {{an explicitly-defaulted copy assignment operator may not have 'const', 'constexpr' or 'volatile' qualifiers}} +}; +struct U { + constexpr U SelfReturn(); + constexpr int SelfParam(U); +}; + +struct V : virtual U { // expected-note {{here}} + constexpr int F() { return 0; } // expected-error {{constexpr member function not allowed in struct with virtual base class}} +}; + +// or a compound-statememt that contains only +constexpr int AllowedStmts() { + // - null statements + ; + + // - static_assert-declarations + static_assert(true, "the impossible happened!"); + + // - typedef declarations and alias-declarations that do not define classes + // or enumerations + typedef int I; + typedef struct S T; + using J = int; + using K = int[sizeof(I) + sizeof(J)]; + // Note, the standard requires we reject this. + struct U; + + // - using-declarations + using N::C; + + // - using-directives + using namespace N; + + // - and exactly one return statement + return sizeof(K) + sizeof(C) + sizeof(K); +} +constexpr int ForStmt() { + for (int n = 0; n < 10; ++n) // expected-error {{statement not allowed in constexpr function}} + return 0; +} +constexpr int VarDecl() { + constexpr int a = 0; // expected-error {{variables cannot be declared in a constexpr function}} + return 0; +} +constexpr int FuncDecl() { + constexpr int ForwardDecl(int); // expected-error {{statement not allowed in constexpr function}} + return ForwardDecl(42); +} +constexpr int ClassDecl1() { + typedef struct { } S1; // expected-error {{types cannot be defined in a constexpr function}} + return 0; +} +constexpr int ClassDecl2() { + using S2 = struct { }; // expected-error {{types cannot be defined in a constexpr function}} + return 0; +} +constexpr int ClassDecl3() { + struct S3 { }; // expected-error {{types cannot be defined in a constexpr function}} + return 0; +} +constexpr int NoReturn() {} // expected-error {{no return statement in constexpr function}} +constexpr int MultiReturn() { + return 0; // expected-note {{return statement}} + return 0; // expected-error {{multiple return statements in constexpr function}} +} + +// - every constructor call and implicit conversion used in initializing the +// return value shall be one of those allowed in a constant expression. +// +// We implement the proposed resolution of DR1364 and ignore this bullet. +// However, we implement the spirit of the check as part of the p5 checking that +// a constexpr function must be able to produce a constant expression. +namespace DR1364 { + constexpr int f(int k) { + return k; // ok, even though lvalue-to-rvalue conversion of a function + // parameter is not allowed in a constant expression. + } + int kGlobal; // expected-note {{here}} + constexpr int f() { // expected-error {{constexpr function never produces a constant expression}} + return kGlobal; // expected-note {{read of non-const}} + } +} |