Compiler crashes with const auto
auto, c++, visual-studio-2010
Solution
The code is ill-formed in C++11: if there is a trailing return type, then the "normal" return type must be `auto` (the C++11 specification states at 8.3.5[dcl.fct]/2 that "T shall be the single type-specifier `auto`," where `T` is the "type" that appears before the name of the function).
All compiler crashes are compiler bugs, so it is a bug that the Visual C++ 2010 compiler crashes when compiling your program. This bug has been fixed, though; Visual C++ 2013 rejects the program with a proper compilation error.
Problem
I am using `Visual Studio 2010` with SP1. The following code crashes the compiler: ``` template <typename T> class MyClass { public: typedef int my_int; const my_int foo(); }; template <typename T> const auto MyClass<T>::foo() -> my_int // auto MyClass<T>::foo() -> const my_int // THIS WORKS! { return my_int(1); } int main() { MyClass<int> m; m.foo(); } ``` Note the commented line that fixes the issue. Am I using `auto` properly here (i.e. `const` qualifier on `auto`)? Is the workaround essentially the exact same thing (i.e. can I safely use it until the compiler's bug is fixed)? And lastly, am I the only one experiencing this issue, if not, I will file a bug report. NOTE: I realize that const here makes little sense. I was trying to replicate the bug in a smaller project where in the actual project I am returning a `const` reference to an object.