ambiguities-1.cpp: In function 'int main()':
ambiguities-1.cpp:13:23: error: '>>' should be '> >' within a nested template argument list

ambiguities-1.cpp: In function 'double f() [with T = std::vector<double>]':
ambiguities-1.cpp:13:26:   instantiated from here
ambiguities-1.cpp:6:3: error: dependent-name 'T:: iterator' is parsed as a non-type, but instantiation yields a type
ambiguities-1.cpp:6:3: note: say 'typename T:: iterator' if a type is meant