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From: martin@xemacs.org To: gcc-gnats@gcc.gnu.org Subject: c++/9053: g++ confused about ambiguity of overloaded function templates Date: Tue, 24 Dec 2002 10:36:00 -0000 [thread overview] Message-ID: <20021224182715.1415.qmail@sources.redhat.com> (raw) >Number: 9053 >Category: c++ >Synopsis: g++ confused about ambiguity of overloaded function templates >Confidential: no >Severity: serious >Priority: medium >Responsible: unassigned >State: open >Class: rejects-legal >Submitter-Id: net >Arrival-Date: Tue Dec 24 10:36:00 PST 2002 >Closed-Date: >Last-Modified: >Originator: Martin Buchholz >Release: g++ 3.2.1 >Organization: >Environment: Linux x86 >Description: g++ must consider whether return types of function templates lead to substitution failure before giving an ambiguity error. Considering only arguments is insufficient. These two function templates template <class T> typename bar<T>::type foo (T); template <class T> typename qux<T>::type foo (T); look ambiguous, but may not be if, when instantiated with a particular type, one of bar<T> or qux<T> leads to substitution failure. Easier to give an example than explain... The code below compiles under icc and Comeau C++, but not g++. (Also: g++ gives ambiguity errors even if foo is never instantiated, which is probably wrong.) g++ gives: ambiguous-template-bug2.cc:10: new declaration `template<class T> qux::type foo(T)' ambiguous-template-bug2.cc:7: ambiguates old declaration `template<class T> bar::type foo(T)' source code: template <typename T> class bar; template <> struct bar<const char*> { typedef void type; }; template <typename T> class qux; template <> struct qux<int> { typedef void type; }; template <typename T> typename bar<T>::type foo (T t) { } template <typename T> typename qux<T>::type foo (T t) { } int main (int argc, char *argv[]) { foo ("foo"); foo (7); } >How-To-Repeat: Compile source code with g++ >Fix: >Release-Note: >Audit-Trail: >Unformatted:
next reply other threads:[~2002-12-24 18:36 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-12-24 10:36 martin [this message] 2002-12-24 11:25 nathan 2002-12-24 14:11 nathan
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