How to get return type of current method?

[Ali Çehreli via Digitalmars-d-learn]

On 04/18/2017 06:40 PM, Meta wrote:
 > On Wednesday, 19 April 2017 at 00:22:14 UTC, Mike B Johnson wrote:
 >> On Tuesday, 18 April 2017 at 23:49:35 UTC, ketmar wrote:
 >>> Mike B Johnson wrote:
 >>>
 >>>> How can I get the return type of the current method without
 >>>> specifying the name or any complexity? Similar to typeof(this).
 >>>
 >>> typeof(return)
 >>
 >> Thanks, sweet and simple!
 >
 > One note: if the function has a return type of `auto`, you cannot use
 > `typeof(return)` within the function.

Actually that works but apparently order matters:

import std.stdio;

bool condition;

auto foo() {
     // Compilation ERROR here
     writeln(typeof(return).stringof);

     if (condition) {
         return 1.5;
     }

     return 42;
}

void main() {
     foo();
}

Error: cannot use typeof(return) inside function foo with inferred 
return type

But if you move typeof(return) after the first return statement, which 
determines the return type of the function per spec, then it works:

auto foo() {
     if (condition) {
         return 1.5;
     }

     // Works here
     writeln(typeof(return).stringof);

     return 42;
}

Prints "double".

Ali