Bug 8542 – crosstalk between template instantiations

With DMD 2.060, the following code compiles and runs correctly with dmd -version=A and dmd -version=B, but it fails to compile with dmd -version=A -version=B The code should compile and run correctly even when both version specifiers are set. import std.stdio, std.algorithm, std.range, std.bigint; template Apply(alias a,T...){ alias a!T Apply; } auto fun(T)(T n, T function(T) i, T function(T) d){ return (z=>((T delegate(T,T) delegate(T delegate(T delegate(T,T),T,T)) AOY) =>((m,e)=>reduce!((a,b)=>AOY((f,a,b)=>z(a)?b:i(f(d(a), b)))(a,b))(zip([(T[] a)=>a.map!((T x)=>m(i(i(n)),x)).array,(T[] a)=>a.map!((T x)=>m(i(i(i(n))),x)).array,delegate(T[] a)=>a.map! (a=>a).array].map!(a=>&Apply!(map!a,T[][])),[[i(n),i(i(n)),i(i(i(n))), i(i(i(i(n)))),i(i(i(i(i(n))))),i(i(i(i(i(i(n))))))], [i(i(i(i(i(n))))),i(i(i(i(i(i(n)))))),i(i(i(i(i(i(i(n))))))),i(i(i(i(i(i(i(i(n)))))))), i(i(i(i(i(i(i(i(i(n))))))))),i(i(i(i(n))))],[e(n,i(n)),e(i(n),i(i(n))),e(i(i(n)),i(n))]] ).map!(t=>t[0](t[1].map!(a=>[a,i(a),m(a,i(i(n)))]).array)).joiner.map!(a=>zip(a,retro(a)) .map!(t=>AOY((f,a,b)=>z(a)?b:i(f(d(a),b)))(t[0],t[1]))).joiner.chain(repeat( i(i(i(i(i(i(i(i(i(i(i(i(n))))))))))))).map!(a=>AOY ((f,a,b)=>z(b)?a:f(d(a),d(b)))(a,i(i(i(i(i(i(i(i(i(i(i(i(i(n))))))))))) )))).take(1))))((T a,T b)=>AOY((f,a,b)=>z(a)?n:AOY((g,a,b)=>z(a)? b:i(g(d(a),b)))(b,f(d(a),b)))(a,b),AOY((h,a,b)=>z(a)?z(b)?i(n):n:z(b)?n:h(d(a),d(b)))))( (a){struct S{ T delegate(T,T) delegate(S) r; } return ((x)=>x(S(x)))((S x)=>(T u,T v)=>a(x.r(x),u,v)); }))((T a)=>a==n); } void main(){ version(A) assert(fun(0,(int a)=>a+1,(int a)=>a-1)==1337); static inc(int[] a){ if(!a.length) return [1]; if(a[0]<0) return a[0..$-1]; return a~(a[$-1]+1); } static dec(int[] a){ if(!a.length) return [-1]; if(a[0]>0) return a[0..$-1]; return a~(a[$-1]-1); } version(B) assert(fun((int[]).init,&inc,&dec).equal(iota(1,1338))); }

importing std.bigint is not required to reproduce.

Are you able to minimize (and reformat in a human way) it a little?

import std.algorithm, std.range; template Apply(alias a,T...){ alias a!T Apply; } auto fun(T)(T n, T function(T) i, T function(T) ){ (z=>(T delegate(T,T) delegate(T delegate(T delegate(T,T),T,T)) AOY) =>((m,e)=>reduce!((a,b)=>AOY((f,a,b)=>z?b:i(a))(a,b))(zip([(T[] a)=>a.map!(x=>m(n,x))].map!(a=>&Apply!(map!a,T[][])),[[n]]).map!(t=>t[0](t[1].map!(a=>[a]).array)).joiner.map!(a=>zip(a,retro(a)).map!(t=>AOY((f,a,b)=>z?b:i(a))(t[0],t[1]))).joiner.chain))((T a,T b)=>AOY((f,a,b)=>z?n:AOY((g,a,b)=>z?b:i(a))(b,f(a,b)))(a,b),AOY))((T a)=>a==n); } void main(){ version(A) fun(0,(int a)=>a+1,(int a)=>a-1); static inc(int[] a){ return a; } static dec(int[] a){ return a; } version(B) fun((int[]).init,&inc,&dec); } I reduced it to that. I fail to got further.

Here's a somewhat simpler case: auto cprod(R1,R2)(R1 A, R2 B) { return zip(sequence!"n"(cast(size_t)0), A.save, B.save, repeat(A), repeat(B)) .map!(function(a) => chain( zip(repeat(a[1]), take(a[4].save,a[0])), zip(take(a[3].save,a[0]+1), repeat(a[2])) )).joiner; } void main() { auto A = sequence!"2*n"(0); auto B = sequence!"2*n+1"(0); auto AB = cprod(A,B); auto C = sequence!"100+n"(0); auto D = sequence!"200+n"(0); auto CD = cprod(C,D); } Produces the error: Error: function test3.cprod!(Sequence!("2*n",Tuple!(int)),Sequence!("2*n+1",Tuple!(int))).cprod.map!(__ funcliteral2).map!(Zip!(Sequence!("n",Tuple!(uint)),Sequence!("100+n",Tuple!(int)),Sequence!("200+n",Tupl e!(int)),Repeat!(Sequence!("100+n",Tuple!(int))),Repeat!(Sequence!("200+n",Tuple!(int))))).map is a neste d function and cannot be accessed from test3.cprod!(Sequence!("100+n",Tuple!(int)),Sequence!("200+n",Tupl e!(int))).cprod Commenting out either the first three lines (A, B, AB) or the second three lines (C, D, CD) makes the problem go away.

I may have duplicated this issue: http://d.puremagic.com/issues/show_bug.cgi?id=8850

Here's an unexpected data point: I discovered that this bug may be linked to the -property compiler flag. To reproduce this odd effect, checkout the code from: https://github.com/D-Programming-Language/phobos/pull/856, build Phobos without unittest, then check the output of the following commands (I tested this on Linux/64): 1) This one compiles just fine: dmd -unittest -m64 std/algorithm.d generated/linux/debug/64/emptymain.d -of/tmp/x 2) This one produces a whole bunch of template crosstalk errors: dmd -property -unittest -m64 std/algorithm.d generated/linux/debug/64/emptymain.d -of/tmp/x

Hmm, the -property effect also happens with the simpler test case I posted earlier in comment 4: $ dmd test.d $ # Compiled successfully $ dmd -property test.d test.d(5): Error: no property 'map' for type 'Zip!(Sequence!("n", Tuple!(ulong)), Sequence!("2*n", Tuple!(int)), Sequence!("2*n+1", Tuple!(int)), Repeat!(Sequence!("2*n", Tuple!(int))), Repeat!(Sequence!("2*n+1", Tuple!(int))))' test.d(17): Error: template instance test.cprod!(Sequence!("2*n", Tuple!(int)), Sequence!("2*n+1", Tuple!(int))) error instantiating test.d(5): Error: no property 'map' for type 'Zip!(Sequence!("n", Tuple!(ulong)), Sequence!("100+n", Tuple!(int)), Sequence!("200+n", Tuple!(int)), Repeat!(Sequence!("100+n", Tuple!(int))), Repeat!(Sequence!("200+n", Tuple!(int))))' test.d(21): Error: template instance test.cprod!(Sequence!("100+n", Tuple!(int)), Sequence!("200+n", Tuple!(int))) error instantiating $

Actually, nevermind that. I just realized that -property requires () for map and joiner because they aren't declared with @property (and UFCS does not alleviate the need for parentheses). The sad thing, though, is that my reduced test case no longer produces template crosstalk in git HEAD. :-(

Hmph. It seems that Timon's original code also compiles fine in git head (without -property). With -property it fails, but seems the reason is that -property requires functions like map and joiner to have trailing parentheses (). The template crosstalk problem seems to have gone away.

git bisect appears to indicate that it was dmd commit 688f7ce593eef75997a2b8f2527d3cd9338692aa that fixed this issue.

Then we can resolve this as WORKSFORME.

Commit pushed to master at https://github.com/D-Programming-Language/phobos https://github.com/D-Programming-Language/phobos/commit/468f7e12c4b1eea25bc88463f700fa62988a90cd Replace unittests to avoid issue 8542.