https://issues.dlang.org/show_bug.cgi?id=18472

Mike Franklin <slavo5150@yahoo.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |betterC
                 CC|                            |slavo5150@yahoo.com

--

https://issues.dlang.org/show_bug.cgi?id=18472

--- Comment #1 from Mike Franklin <slavo5150@yahoo.com> ---
The test doesn't compile with 2.078.3. 2.078.3 does not include the TypeInfo check, so at most this is a diagnostic regression.

https://run.dlang.io/is/fvj8jb

/dlang/dmd/linux/bin64/../../src/phobos/std/range/primitives.d(405): Error:
static assert  "Cannot put a const(char)[] into a Appender!string."
/dlang/dmd/linux/bin64/../../src/phobos/std/format.d(1172):        instantiated
from here: put!(Appender!string, const(char)[])
/dlang/dmd/linux/bin64/../../src/phobos/std/format.d(473):        instantiated
from here: writeUpToNextSpec!(Appender!string)
/dlang/dmd/linux/bin64/../../src/phobos/std/format.d(5831):        instantiated
from here: formattedWrite!(Appender!string, char, string, string)
onlineapp.d(5):        instantiated from here: format!(char, string, string)

Do you have a test that will demonstrate a successful build prior to the TypeInfo check introduced in 2.079?

--

https://issues.dlang.org/show_bug.cgi?id=18472

Martin Nowak <code@dawg.eu> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |code@dawg.eu
            Summary|betterC: cannot use format  |[Reg 2.078] betterC: cannot
                   |at compile time.            |use format at compile time.

--- Comment #2 from Martin Nowak <code@dawg.eu> ---
cat > bug.d << CODE
import std.format;
import std.stdio;
void main()
{
    enum s = "%1$s,%2$s".format("foo","bar");
    writeln(s);
}
CODE
dmd -c -betterC bug.d
----
/home/dawg/dlang/dmd-2.078.0/linux/bin64/../../src/phobos/std/range/primitives.d(405):
Error: static assert  "Cannot put a const(char)[] into a Appender!string."
/home/dawg/dlang/dmd-2.078.0/linux/bin64/../../src/phobos/std/format.d(1172):
     instantiated from here: put!(Appender!string, const(char)[])
/home/dawg/dlang/dmd-2.078.0/linux/bin64/../../src/phobos/std/format.d(473):
    instantiated from here: writeUpToNextSpec!(Appender!string)
/home/dawg/dlang/dmd-2.078.0/linux/bin64/../../src/phobos/std/format.d(5831):
     instantiated from here: formattedWrite!(Appender!string, char, string,
string)
/home/dawg/Code/D/bug.d(5):        instantiated from here: format!(char,
string, string)
----

Confirmed that this stopped to work with 2.078.0, the error looks rather weird, as betterC shouldn't change types.

Also indeed with 2.079.0-beta.1 the error message is now about using TypeInfo.
----
/home/dawg/dlang/dmd-2.079.0-beta.1/linux/bin64/../../src/phobos/std/array.d(2889): Error: TypeInfo cannot be used with -betterC
----

The test case compiles fine with 2.077.1.

--

https://issues.dlang.org/show_bug.cgi?id=18472

--- Comment #3 from Nicholas Wilson <iamthewilsonator@hotmail.com> ---
(In reply to Martin Nowak from comment #2)
> cat > bug.d << CODE
> import std.format;
> import std.stdio;
> void main()
> {
>     enum s = "%1$s,%2$s".format("foo","bar");
>     writeln(s);
> }
> CODE
> dmd -c -betterC bug.d
> ----
> /home/dawg/dlang/dmd-2.078.0/linux/bin64/../../src/phobos/std/range/
> primitives.d(405): Error: static assert  "Cannot put a const(char)[] into a
> Appender!string."
> /home/dawg/dlang/dmd-2.078.0/linux/bin64/../../src/phobos/std/format.d(1172):
> instantiated from here: put!(Appender!string, const(char)[])
> /home/dawg/dlang/dmd-2.078.0/linux/bin64/../../src/phobos/std/format.d(473):
> instantiated from here: writeUpToNextSpec!(Appender!string)
> /home/dawg/dlang/dmd-2.078.0/linux/bin64/../../src/phobos/std/format.d(5831):
> instantiated from here: formattedWrite!(Appender!string, char, string,
> string)
> /home/dawg/Code/D/bug.d(5):        instantiated from here: format!(char,
> string, string)
> ----
> 
> Confirmed that this stopped to work with 2.078.0, the error looks rather weird, as betterC shouldn't change types.
> 

Indeed that is issue 18101 which was fixed to check typeinfo, but now also fails at compile time.

> Also indeed with 2.079.0-beta.1 the error message is now about using TypeInfo.
> ----
> /home/dawg/dlang/dmd-2.079.0-beta.1/linux/bin64/../../src/phobos/std/array. d(2889): Error: TypeInfo cannot be used with -betterC
> ----
> 
> The test case compiles fine with 2.077.1.

That sounds about the right timeframe.

--

https://issues.dlang.org/show_bug.cgi?id=18472

--- Comment #4 from Mike Franklin <slavo5150@yahoo.com> ---
Isn't this then a duplicate of Issue 18101?  In other words, if Issue 18101 were solved, there wouldn't be a need for TypeInfo, and therefore the TypeInfo error would not be triggered?

--

https://issues.dlang.org/show_bug.cgi?id=18472

Mike Franklin <slavo5150@yahoo.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://issues.dlang.org/sh
                   |                            |ow_bug.cgi?id=18101

--

https://issues.dlang.org/show_bug.cgi?id=18472

Rainer Schuetze <r.sagitario@gmx.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |r.sagitario@gmx.de

--- Comment #5 from Rainer Schuetze <r.sagitario@gmx.de> ---
Here's a simpler test case:

module betterc;
enum b = typeid(size_t) is typeid(uint);

>dmd -betterC -c betterc.d
betterc.d(2): Error: TypeInfo cannot be used with -betterC

--

https://issues.dlang.org/show_bug.cgi?id=18472

--- Comment #6 from Mike Franklin <slavo5150@yahoo.com> ---
(In reply to Rainer Schuetze from comment #5)
> Here's a simpler test case:
> 
> module betterc;
> enum b = typeid(size_t) is typeid(uint);

At https://dlang.org/spec/betterc.html under the "Not Available" section:

> 2. TypeInfo and ModuleInfo

So, it is by design that any call to `typeid` is going to fail when compiled with `-betterC`.

This specific issue is about not being able to use `format` in `-betterC`. Perhaps the reason for that is because `format` relies on runtime type information (i.e. TypeInfo).  So the solution, specific to this issue, would not be allow uses of `typeid` in `-betterC`, but rather to remove the dependency of `format` on runtime type information (if that's even possible).

D has excellent facilities for doing introspection at compile-time, so it may be possible to look to those facilities in concert with templates to find a solution that does not rely on runtime type information.

It would likely also help to begin replacing compiler-generated calls to runtime hooks that depend on `TypeInfo` with templates.

See also https://forum.dlang.org/post/mr7a65$2hc$1@digitalmars.com

--

https://issues.dlang.org/show_bug.cgi?id=18472

--- Comment #7 from Rainer Schuetze <r.sagitario@gmx.de> ---
I think the main issue is that the compiler does not distinguish between information needed at compile time and what's necessary inside the object file.

--

https://issues.dlang.org/show_bug.cgi?id=18472

--- Comment #8 from Mike Franklin <slavo5150@yahoo.com> ---
(In reply to Rainer Schuetze from comment #7)
> I think the main issue is that the compiler does not distinguish between information needed at compile time and what's necessary inside the object file.

Ok, I understand now:  `enum b = typeid(size_t) is typeid(uint);` should be
evaluated at compile time, and I the -betterC limitations should only apply at
runtime.

--