[Issue 13845] Error using alias of typeof(null) as unnamed lambda parameter

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13845

Kenji Hara <k.hara.pg at gmail.com> changed:

           What    |Removed                     |Added
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             Status|NEW                         |RESOLVED
         Resolution|---                         |INVALID

--- Comment #2 from Kenji Hara <k.hara.pg at gmail.com> ---
(In reply to Peter Alexander from comment #1)
> alias Null = typeof(null);
> auto a = (int) => 0;           // ok
> auto b = (typeof(null)) => 0;  // ok

`int` and `typeof(null)` are definitely parsed as types.

> auto c = (Null x) => 0;        // ok

`Null x` is parsed as a parameter, typed Null and parameter name is `x`.

> auto d = (Null) => 0;          // error
> 
> Error: variable bug.d type void is inferred from initializer (Null) => 0,
> and variables cannot be of type void

If a lambda parameter is an identifier, it's treated as the "parameter name".
Therefore it is equivalent with:

  auto d = (x) => 0;

and compiler cannot infer the lambda parameter type so there's no "target"
type.

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