Compiler hints, inlining and syntax consistency

[Chris Cain]

On Saturday, 28 December 2013 at 18:47:52 UTC, Chris Cain wrote:
> ...snip...
>
> There you go. Use it like:
>
> ```
> someGenericAlgorithm(assumeWalkLengthOK(myContainer));
> ```
>
> Squelches the error message and documents the intent. Could be 
> better, but it saves us writing a language feature for it.

I keep forgetting to use voldemort types, and in this case it 
really makes sense:

     import std.range;
     auto assumeWalkLengthOK(T)(T thing)
     if(isInputRange!T)
     {
         struct Result
         {
             T wrapped;
             size_t length()
             {
                 return wrapped.walkLength();
             }
             alias wrapped this;
         }
         return Result(thing);
     }

Same usage, 
`someGenericAlgorithm(assumeWalkLengthOK(myContainer));` (I 
didn't actually run this through dmd, but it should work in 
theory)