http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57243
Bug ID: 57243 Summary: Using auto in range based for with templated container in templated function requires extraneous template qualifier Product: gcc Version: 4.8.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: w.shane.grant at gmail dot com Using the auto keyword in a range based for loop under three conditions related to templating requires an unnecessary use of the template qualifier for compilation to happen successfully: 1. The container being iterated is templated 2. The range based for loop is inside of a template function 3. The iterated item has a template function Here is a minimal example: struct snarf { template <class T> void get() {} }; template <class T> struct container { snarf * begin() { return nullptr; } snarf * end() { return nullptr; } }; template <class T> void foo() { container<int> arr; for( auto i : arr ) i.get<int>(); } int main() { return 0; } The issue goes away if any of the following happen: - foo is made a non template function - arr is made a non template container - auto is replaced with the actual type (snarf in this example) - the function called on the range declaration (i) is not templated - the template keyword is used to disambiguate the call to get - the range based for loop is replaced with a standard for loop over the iterators (auto works fine here) Issue seems to happen with both versions of g++ I have installed (4.7.3 and g++ 4.8.1 20130401) but not under clang (version 3.3 (trunk 178896)).