• Andrei Alexandrescu (2/2) Aug 24 2016 Just got the error above. Is this fundamental or an implementation
• ketmar (15/17) Aug 24 2016 fundamental. interpreter operates only on fully semanticed
• Walter Bright (6/20) Aug 24 2016 From the test suite:
• ketmar (6/7) Aug 24 2016 yeah, this is it. template instantiation wants semantic, and we
• ketmar (2/2) Aug 24 2016 p.s. i just thought that Andrei hits this somewhere in his own
• Walter Bright (3/5) Aug 24 2016 It's fine if Andrei produces a sample, and it can be compared with the e...
• Andrei Alexandrescu (3/9) Aug 25 2016 It's similar. I got convinced my code was attempting something
• Timon Gehr (15/26) Aug 24 2016 (The remainder of the post is describing implementation details; this

Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:

Just got the error above. Is this fundamental or an implementation 
artifact? -- Andrei

ketmar <ketmar ketmar.no-ip.org> writes:

On Thursday, 25 August 2016 at 02:20:31 UTC, Andrei Alexandrescu 
wrote:
 Just got the error above. Is this fundamental or an 
 implementation artifact? -- Andrei

fundamental. interpreter operates only on fully semanticed 
functions, where all the analysis, type inferencing and lowering 
is already complete (otherwise interpreter have to reimplement 
*all* the frontend again, to do exactly same work).

the error mesage you got means that CTFE tried to execute 
something that is still in semantic analysis stage.

this *may* be somewhat relaxed by doing lazy semantic (i.e. only 
mark something for "future analysis", and do real thing when 
interpreter/compiler really need semantic results), but it will 
require a huge efforts to implement this in current FE 
architecture.

still, this may be some obscure bug in semantic analyser, so it 
will be good to see a minified sample that triggers this.

Walter Bright <newshound2 digitalmars.com> writes:

On 8/24/2016 8:11 PM, ketmar wrote:
 On Thursday, 25 August 2016 at 02:20:31 UTC, Andrei Alexandrescu wrote:
 Just got the error above. Is this fundamental or an implementation artifact?
 -- Andrei

 fundamental. interpreter operates only on fully semanticed functions, where all
 the analysis, type inferencing and lowering is already complete (otherwise
 interpreter have to reimplement *all* the frontend again, to do exactly same
work).

 the error mesage you got means that CTFE tried to execute something that is
 still in semantic analysis stage.

 this *may* be somewhat relaxed by doing lazy semantic (i.e. only mark something
 for "future analysis", and do real thing when interpreter/compiler really need
 semantic results), but it will require a huge efforts to implement this in
 current FE architecture.

 still, this may be some obscure bug in semantic analyser, so it will be good to
 see a minified sample that triggers this.

 From the test suite:

diag8714.d:fail_compilation/diag8714.d(9): Error: function diag8714.foo
circular 
dependency. Functions cannot be interpreted while being compiled

fail133.d:fail_compilation/fail133.d(13): Error: function D main circular 
dependency. Functions cannot be interpreted while being compiled

ketmar <ketmar ketmar.no-ip.org> writes:

On Thursday, 25 August 2016 at 04:39:01 UTC, Walter Bright wrote:
 From the test suite

yeah, this is it. template instantiation wants semantic, and we 
are already semanticing the function.

while this restriction can be somewhat relaxed, it will require 
huge amount of hacks, will be PITA to maintain, and adds very 
little value (i think) in exchange.

ketmar <ketmar ketmar.no-ip.org> writes:

p.s. i just thought that Andrei hits this somewhere in his own 
code, so i asked for a sample.

Walter Bright <newshound2 digitalmars.com> writes:

On 8/24/2016 10:51 PM, ketmar wrote:
 p.s. i just thought that Andrei hits this somewhere in his own code, so i asked
 for a sample.

It's fine if Andrei produces a sample, and it can be compared with the existing 
stuff in the test suite to see if it is fundamentally different.

Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:

On 08/25/2016 02:10 AM, Walter Bright wrote:
 On 8/24/2016 10:51 PM, ketmar wrote:
 p.s. i just thought that Andrei hits this somewhere in his own code,
 so i asked
 for a sample.

 It's fine if Andrei produces a sample, and it can be compared with the
 existing stuff in the test suite to see if it is fundamentally different.

It's similar. I got convinced my code was attempting something 
unreasonable. Thanks! -- Andrei

Timon Gehr <timon.gehr gmx.ch> writes:

On 25.08.2016 05:11, ketmar wrote:
 On Thursday, 25 August 2016 at 02:20:31 UTC, Andrei Alexandrescu wrote:
 Just got the error above. Is this fundamental or an implementation
 artifact? -- Andrei

 fundamental.

(The remainder of the post is describing implementation details; this 
doesn't explain why the limitation is fundamental.)

 interpreter operates only on fully semanticed functions,
 where all the analysis, type inferencing and lowering is already
 complete (otherwise interpreter have to reimplement *all* the frontend
 again, to do exactly same work).
 ...

Usually, to do exactly the same work, one would just use exactly the 
same code.

 the error mesage you got means that CTFE tried to execute something that
 is still in semantic analysis stage.

No, it means CTFE tried to execute a function of which some parts are 
still in semantic analysis stage. E.g., it is clear what the following 
function should mean, if it was assigned a meaning:

int foo(int x){
     if(x==0) return 1;
     enum r=foo(0);
     return r;
}

Usually CTFE only fails if the dynamic branch actually taken runs into a 
problem, so this is somewhat inconsistent.