[Issue 7492] [CTFE] Error at assign to immutable character array

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=7492

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
           See Also|                            |https://issues.dlang.org/sh
                   |                            |ow_bug.cgi?id=14017
         Resolution|INVALID                     |---

--- Comment #7 from Kenji Hara <k.hara.pg at gmail.com> ---
(In reply to Denis Shelomovskij from comment #5)
> Filed issue 14017.

By looking the code in 14017, I recognized the real issue at last...

Full code to illustrate issue.

 int[] f() { return new  int[](1); }
char[] g() { return new char[](1); }
immutable( int[]) a = f();  // [A] accepted
immutable(char[]) s = g();  // [B] rejected

If we just only consider type system, both conversions:
   int[] to immutable( int[])
  char[] to immutable(char[])
are not possible.

But if we also consider CTFE, we can regard that the function calls will be
replaced with the literals that returned by CTFE:
  immutable( int[]) a = [0];
  immutable(char[]) s = ['\xff'];
and literals can be convertible to the variable type.

---

By looking dmd internals, current semantic process is nearly the latter
replacement model. And maybe the [B] case is happened by the issue in the
interpreter code for scrubbing CTFE return value.

But, at the same time the case [A] looks like a kind of type system breaking.

Anyway, at least it's an inconsistent compiler behavior. I reopen this.

--