Enum literals, good? bad? what do you think?

[John Colvin]

On Thursday, 22 July 2021 at 16:41:30 UTC, Paul Backus wrote:
>
> IMO D's target-typed literals (also called "polysemous 
> literals") are also a misfeature. They lead to weird, 
> unintuitive situations where seemingly-equivalent code has 
> different behavior; for example:
>
> ```d
> import std.stdio;
>
> void fun(double[] arr) { writeln("double"); }
> void fun(T)(T[] arr) { writeln(T.stringof); }
>
> void main()
> {
>     fun([1, 2, 3]);
>     auto arr = [1, 2, 3];
>     fun(arr);
> }
> ```
>
> A language with fully-context-aware type inference would infer 
> both arrays as `double[]`. A language with 
> fully-context-independent type inference would infer both as 
> `int[]`.
>
> In D, however, we get the worst of both worlds: type inference 
> is *mostly* context-independent (so we have to add type 
> annotations even in cases that are unambiguous), but there are 
> a few special cases where context is taken into account (so we 
> have to be mindful of context when refactoring, since a change 
> in context could change the inferred type of an expression).

It’s not so bad IMO. Type inference in D isn’t far from just 
“forward, one step at a time”, which is easy to understand but 
still very powerful.