Author: sepavloff Date: Thu Jun 8 01:31:19 2017 New Revision: 304965 URL: http://llvm.org/viewvc/llvm-project?rev=304965&view=rev Log: Do not inherit default arguments for friend function in class template.
A function declared in a friend declaration may have declarations prior to the containing class definition. If such declaration defines default argument, the friend function declaration inherits them. This behavior causes problems if the class where the friend is declared is a template: during the class instantiation the friend function looks like if it had default arguments, so error is triggered. With this change friend functions declared in class templates do not inherit default arguments. Actual set of them will be defined at the point where the containing class is instantiated. This change fixes PR12724. Differential Revision: https://reviews.llvm.org/D30393 Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp cfe/trunk/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p4.cpp Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=304965&r1=304964&r2=304965&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original) +++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Thu Jun 8 01:31:19 2017 @@ -547,17 +547,23 @@ bool Sema::MergeCXXFunctionDecl(Function Diag(OldParam->getLocation(), diag::note_previous_definition) << OldParam->getDefaultArgRange(); } else if (OldParamHasDfl) { - // Merge the old default argument into the new parameter. - // It's important to use getInit() here; getDefaultArg() - // strips off any top-level ExprWithCleanups. - NewParam->setHasInheritedDefaultArg(); - if (OldParam->hasUnparsedDefaultArg()) - NewParam->setUnparsedDefaultArg(); - else if (OldParam->hasUninstantiatedDefaultArg()) - NewParam->setUninstantiatedDefaultArg( - OldParam->getUninstantiatedDefaultArg()); - else - NewParam->setDefaultArg(OldParam->getInit()); + // Merge the old default argument into the new parameter unless the new + // function is a friend declaration in a template class. In the latter + // case the default arguments will be inherited when the friend + // declaration will be instantiated. + if (New->getFriendObjectKind() == Decl::FOK_None || + !New->getLexicalDeclContext()->isDependentContext()) { + // It's important to use getInit() here; getDefaultArg() + // strips off any top-level ExprWithCleanups. + NewParam->setHasInheritedDefaultArg(); + if (OldParam->hasUnparsedDefaultArg()) + NewParam->setUnparsedDefaultArg(); + else if (OldParam->hasUninstantiatedDefaultArg()) + NewParam->setUninstantiatedDefaultArg( + OldParam->getUninstantiatedDefaultArg()); + else + NewParam->setDefaultArg(OldParam->getInit()); + } } else if (NewParamHasDfl) { if (New->getDescribedFunctionTemplate()) { // Paragraph 4, quoted above, only applies to non-template functions. Modified: cfe/trunk/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p4.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p4.cpp?rev=304965&r1=304964&r2=304965&view=diff ============================================================================== --- cfe/trunk/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p4.cpp (original) +++ cfe/trunk/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p4.cpp Thu Jun 8 01:31:19 2017 @@ -73,3 +73,36 @@ void Test () } } // namespace + +namespace pr12724 { + +void func_01(bool param = true); +class C01 { +public: + friend void func_01(bool param); +}; + +void func_02(bool param = true); +template<typename T> +class C02 { +public: + friend void func_02(bool param); +}; +C02<int> c02; + +void func_03(bool param); +template<typename T> +class C03 { +public: + friend void func_03(bool param); +}; +void func_03(bool param = true); +C03<int> c03; + +void main() { + func_01(); + func_02(); + func_03(); +} + +} // namespace pr12724 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
