Bug 7919 – Sample code works on GDC but fails with DMD

The code: import std.algorithm ; import std.range ; import std.stdio ; import core.thread ; int main ( immutable string[] args ) { auto threads = array ( map ! ( ( int a ) { void delegate ( ) f ( ) { return delegate ( ) { writeln ( a ) ; } ; } return new Thread ( f ) ; } ) ( iota ( 10 ) ) ) ; foreach ( t ; threads ) { t.start ( ) ; } foreach ( t ; threads ) { t.join ( ) ; } return 0 ; } compiles and runs as expected when using GDC on Linux: Using built-in specs. COLLECT_GCC=gdc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.6/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Debian 4.6.3-1' --with-bugurl=file:///usr/share/doc/gdc-4.6/README.Bugs --enable-languages=c,c++,d --prefix=/usr --program-suffix=-4.6 --enable-shared --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.6 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap --enable-plugin --disable-multilib --with-arch-32=i586 --with-tune=generic --disable-libquadmath --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.6.3 (Debian 4.6.3-1) However when using DMD 2.059, the compilation fails with the error: /home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/traits.d(1482): Error: void does not have a default initializer /home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/traits.d(1493): Error: template instance std.traits.hasIndirections!(Thread).Impl!(void[168LU]) error instantiating /home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/array.d(143): instantiated from here: hasIndirections!(Thread) /home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/array.d(143): Error: template instance std.traits.hasIndirections!(Thread) error instantiating /home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/array.d(243): Error: template instance std.array.blockAttribute!(Thread) error instantiating /home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/array.d(194): instantiated from here: arrayAllocImpl!(false,Thread[],uint) /home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/array.d(42): instantiated from here: uninitializedArray!(Thread[],uint) initializingWithAMap.d(9): instantiated from here: array!(Result) /home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/array.d(194): Error: template instance std.array.arrayAllocImpl!(false,Thread[],uint) error instantiating /home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/array.d(42): instantiated from here: uninitializedArray!(Thread[],uint) initializingWithAMap.d(9): instantiated from here: array!(Result) /home/users/russel/lib.Linux.x86_64/DMD2/bin64/../../src/phobos/std/array.d(42): Error: template instance std.array.uninitializedArray!(Thread[],uint) error instantiating initializingWithAMap.d(9): instantiated from here: array!(Result) initializingWithAMap.d(9): Error: template instance std.array.array!(Result) error instantiating

I am just going to point out that gdc is on 2.057 release. And my best assumption would be this would be a library bug, not a compiler.

There are related two issues. 1. The implementation of core.thread.Thread class was hidden by adding hand-made di file in 2.059. It hides actual class members with 'void[N] data'. 2. std.traits.hasIndirections doesn't define its behavior against void[N] type. I think hasIndirections template should return true for void static array types, because void data *may* have some indirections - it's conservative way. But I'm not sure. (In reply to comment #1) > I am just going to point out that gdc is on 2.057 release. And my best > assumption would be this would be a library bug, not a compiler. Yes, this is druntime or Phobos issue, not compiler's. I'll change 'Component' from dmd to Phobos.

Just to add a bit more data: the code works as anticipated with DMD 2.058.

Commits pushed to master at https://github.com/D-Programming-Language/phobos https://github.com/D-Programming-Language/phobos/commit/e3cfaeb005e42d5397f548a9cd6beb28264c85e9 fix Issue 7919 - Sample code works on GDC but fails with DMD https://github.com/D-Programming-Language/phobos/commit/a47332ca0df2cd4ea714e7ab31e5376fd72adb93 Merge pull request #540 from 9rnsr/fix7919 Issue 7919 - Sample code works on GDC but fails with DMD