Make const, immutable, inout, and shared illegal as function attributes on the left-hand side of a function

[Brad Anderson via Digitalmars-d]

On Thursday, 9 October 2014 at 08:50:52 UTC, Martin Nowak wrote:
> Kenji just proposed a slightly controversial pull request so I 
> want to reach out for more people to discuss it's tradeoffs.
> It's about deprecating function qualifiers on the left hand 
> side of a function.

+1.

Prefixed const is so often a mistaken attempt to return a const 
that when I see someone post for help in IRC about "cannot 
implicitly convert expression" I immediately look for a "this" in 
the error message because that usually means they are using 
prefixed const function attribute when they intended to return a 
const variable.

This reminds me quite a bit about Walter's explanation on FLOSS 
Weekly about why D disallows shadowing local variables. It can be 
used correctly just fine but it's so often used incorrectly that 
we're better off disallowing it completely.