Is my book's discussion of lambda return types wrong?

Question

My book says this:

Lambdas with function bodies that contain anything other than a single return statement that do not specify a return type return vo

Answer 1

If you use popular compilers (gcc, Visual Studio), you usually don't need to specify return type as long as the compiler is able to determine it unambiguously - like in your example.

The following example shows a lambda, which requires explicit return type information:

auto lambda = [](bool b) -> float
    { 
        if (b) 
            return 5.0f; 
        else 
            return 6.0; 
    };

I asked Bjarne Stroustrup regarding this matter, his comment:

I do not know if C++11 allows the deduction of the return type is there are several return statements with identical return type. If not, that's planned for C++14.