From: Zhihao Yuan Date: Mon, 11 Dec 2017 18:29:54 +0000 (+0000) Subject: P0620 follow-up: deducing `auto` from braced-init-list in new expr X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e14d055b29b583feead78d2dbf704a67ed4000ec;p=clang P0620 follow-up: deducing `auto` from braced-init-list in new expr Summary: This is a side-effect brought in by p0620r0, which allows other placeholder types (derived from `auto` and `decltype(auto)`) to be usable in a `new` expression with a single-clause //braced-init-list// as its initializer (8.3.4 [expr.new]/2). N3922 defined its semantics. References: http://wg21.link/p0620r0 http://wg21.link/n3922 Reviewers: rsmith, aaron.ballman Reviewed By: rsmith Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D39451 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@320401 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td index b5e1b09666..14db7bf556 100644 --- a/include/clang/Basic/DiagnosticSemaKinds.td +++ b/include/clang/Basic/DiagnosticSemaKinds.td @@ -1988,8 +1988,9 @@ def err_auto_var_requires_init : Error< "declaration of variable %0 with deduced type %1 requires an initializer">; def err_auto_new_requires_ctor_arg : Error< "new expression for type %0 requires a constructor argument">; -def err_auto_new_list_init : Error< - "new expression for type %0 cannot use list-initialization">; +def ext_auto_new_list_init : Extension< + "ISO C++ standards before C++17 do not allow new expression for " + "type %0 to use list-initialization">, InGroup; def err_auto_var_init_no_expression : Error< "initializer for variable %0 with type %1 is empty">; def err_auto_var_init_multiple_expressions : Error< diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp index cd0d715741..9c842ded1e 100644 --- a/lib/Sema/SemaExprCXX.cpp +++ b/lib/Sema/SemaExprCXX.cpp @@ -1748,20 +1748,27 @@ Sema::BuildCXXNew(SourceRange Range, bool UseGlobal, if (AllocType.isNull()) return ExprError(); } else if (Deduced) { + bool Braced = (initStyle == CXXNewExpr::ListInit); + if (NumInits == 1) { + if (auto p = dyn_cast_or_null(Inits[0])) { + Inits = p->getInits(); + NumInits = p->getNumInits(); + Braced = true; + } + } + if (initStyle == CXXNewExpr::NoInit || NumInits == 0) return ExprError(Diag(StartLoc, diag::err_auto_new_requires_ctor_arg) << AllocType << TypeRange); - if (initStyle == CXXNewExpr::ListInit || - (NumInits == 1 && isa(Inits[0]))) - return ExprError(Diag(Inits[0]->getLocStart(), - diag::err_auto_new_list_init) - << AllocType << TypeRange); if (NumInits > 1) { Expr *FirstBad = Inits[1]; return ExprError(Diag(FirstBad->getLocStart(), diag::err_auto_new_ctor_multiple_expressions) << AllocType << TypeRange); } + if (Braced && !getLangOpts().CPlusPlus17) + Diag(Initializer->getLocStart(), diag::ext_auto_new_list_init) + << AllocType << TypeRange; Expr *Deduce = Inits[0]; QualType DeducedType; if (DeduceAutoType(AllocTypeInfo, Deduce, DeducedType) == DAR_Failed) diff --git a/test/CXX/expr/expr.unary/expr.new/p2-cxx0x.cpp b/test/CXX/expr/expr.unary/expr.new/p2-cxx0x.cpp index 7305bd1f53..a3a2f712c8 100644 --- a/test/CXX/expr/expr.unary/expr.new/p2-cxx0x.cpp +++ b/test/CXX/expr/expr.unary/expr.new/p2-cxx0x.cpp @@ -9,12 +9,14 @@ struct only { void f() { only p = new const auto (0); only q = new (auto) (0.0); + only r = new auto {'a'}; new auto; // expected-error{{new expression for type 'auto' requires a constructor argument}} new (const auto)(); // expected-error{{new expression for type 'const auto' requires a constructor argument}} new (auto) (1,2,3); // expected-error{{new expression for type 'auto' contains multiple constructor arguments}} - new auto {1,2,3}; // expected-error{{new expression for type 'auto' cannot use list-initialization}} - new auto ({1,2,3}); // expected-error{{new expression for type 'auto' cannot use list-initialization}} + new auto {}; // expected-error{{new expression for type 'auto' requires a constructor argument}} + new auto {1,2,3}; // expected-error{{new expression for type 'auto' contains multiple constructor arguments}} + new auto ({1,2,3}); // expected-error{{new expression for type 'auto' contains multiple constructor arguments}} } void p2example() { diff --git a/test/CXX/expr/expr.unary/expr.new/p2-cxx14.cpp b/test/CXX/expr/expr.unary/expr.new/p2-cxx14.cpp new file mode 100644 index 0000000000..70bbc4805c --- /dev/null +++ b/test/CXX/expr/expr.unary/expr.new/p2-cxx14.cpp @@ -0,0 +1,10 @@ +// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++14 -pedantic + +void f() { + new auto('a'); + new auto {2}; // expected-warning {{ISO C++ standards before C++17 do not allow new expression for type 'auto' to use list-initialization}} + new auto {1, 2}; // expected-error{{new expression for type 'auto' contains multiple constructor arguments}} + new auto {}; // expected-error{{new expression for type 'auto' requires a constructor argument}} + new decltype(auto)({1}); // expected-warning {{ISO C++ standards before C++17 do not allow new expression for type 'decltype(auto)' to use list-initialization}} + new decltype(auto)({1, 2}); // expected-error{{new expression for type 'decltype(auto)' contains multiple constructor arguments}} +} diff --git a/test/CXX/expr/expr.unary/expr.new/p2-cxx1z.cpp b/test/CXX/expr/expr.unary/expr.new/p2-cxx1z.cpp new file mode 100644 index 0000000000..6e76075ab1 --- /dev/null +++ b/test/CXX/expr/expr.unary/expr.new/p2-cxx1z.cpp @@ -0,0 +1,11 @@ +// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++14 +// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++17 -pedantic + +void f() { + new auto('a'); + new auto {2}; + new auto {1, 2}; // expected-error{{new expression for type 'auto' contains multiple constructor arguments}} + new auto {}; // expected-error{{new expression for type 'auto' requires a constructor argument}} + new decltype(auto)({1}); + new decltype(auto)({1, 2}); // expected-error{{new expression for type 'decltype(auto)' contains multiple constructor arguments}} +} diff --git a/test/SemaCXX/cxx0x-initializer-stdinitializerlist.cpp b/test/SemaCXX/cxx0x-initializer-stdinitializerlist.cpp index 78ebc048b2..860a4aa6c6 100644 --- a/test/SemaCXX/cxx0x-initializer-stdinitializerlist.cpp +++ b/test/SemaCXX/cxx0x-initializer-stdinitializerlist.cpp @@ -148,7 +148,7 @@ void auto_deduction() { } void dangle() { - new auto{1, 2, 3}; // expected-error {{cannot use list-initialization}} + new auto{1, 2, 3}; // expected-error {{new expression for type 'auto' contains multiple constructor arguments}} new std::initializer_list{1, 2, 3}; // expected-warning {{at the end of the full-expression}} }