Author: timshen Date: Wed Aug 2 17:18:11 2017 New Revision: 309908 URL: http://llvm.org/viewvc/llvm-project?rev=309908&view=rev Log: [Sema] Add a comment on an identified bug on default arguments.
Summary: The mis-compile is triggered by internal code, but I haven't reduced it to a small piece of code. Add a FIXME here, since a decent fix doesn't seem to be trivial. The decent fix can be changing Decl::Init to PointerUnion<Stmt *, EvaluatedStmt *, ParamVarDecl *>, and make setUninstantiatedDefaultArg take a ParamVarDecl *, which contains the Expr * as the default argument. This way, getTemplateInstantiationArgs can take that ParamVarDecl and do the right thing. Reviewers: rsmith Subscribers: sanjoy, cfe-commits Differential Revision: https://reviews.llvm.org/D36253 Modified: cfe/trunk/lib/Sema/SemaExpr.cpp Modified: cfe/trunk/lib/Sema/SemaExpr.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=309908&r1=309907&r2=309908&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaExpr.cpp (original) +++ cfe/trunk/lib/Sema/SemaExpr.cpp Wed Aug 2 17:18:11 2017 @@ -4477,6 +4477,22 @@ bool Sema::CheckCXXDefaultArgExpr(Source *this, ExpressionEvaluationContext::PotentiallyEvaluated, Param); // Instantiate the expression. + // + // FIXME: Pass in a correct Pattern argument, otherwise + // getTemplateInstantiationArgs uses the lexical context of FD, e.g. + // + // template<typename T> + // struct A { + // static int FooImpl(); + // + // template<typename Tp> + // // bug: default argument A<T>::FooImpl() is evaluated with 2-level + // // template argument list [[T], [Tp]], should be [[Tp]]. + // friend A<Tp> Foo(int a); + // }; + // + // template<typename T> + // A<T> Foo(int a = A<T>::FooImpl()); MultiLevelTemplateArgumentList MutiLevelArgList = getTemplateInstantiationArgs(FD, nullptr, /*RelativeToPrimary=*/true); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
