Double-inference error

[Andy Ferris]

Hi,

I'm getting a strange "double inference" error from StaticArrays.jl. I have some `@pure` functions which are doing some funky things with types (tracing parameters of T.name.primary up the type tree and back down again for a function called `similar_type()`). When I make them normal functions or generated functions, there is no error, but if I make the two functions `@pure` then *sometimes* I get the error message below (though I think the code is working, somehow). By sometimes, I mean I can't reproduce it at the REPL but some of my tests cause this error (but not others, which follow eventually exactly the same code path!).

My question is: I can't create a minimal reproducible example, so should I create an issue anyway? Or can anyway shed some light on what might be going on?

Thanks,

Andy

WARNING: An error occured during inference. Type inference is now partially disabled.rec_backtrace at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\stackwalk.c:84

record_backtrace at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\task.c:232

jl_throw at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\task.c:529

abstract_eval at .\inference.jl:1149

unknown function (ip: 0000000061B188AC)

jl_call_method_internal at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\julia_internal.h:175

abstract_interpret at .\inference.jl:1201

unknown function (ip: 0000000061B164BC)

jl_call_method_internal at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\julia_internal.h:175

typeinf_frame at .\inference.jl:1680

typeinf_loop at .\inference.jl:1623

unknown function (ip: 0000000061B15DE1)

jl_call_method_internal at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\julia_internal.h:175

typeinf_ext at .\inference.jl:1594

jl_call_method_internal at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\julia_internal.h:175

jl_apply at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\julia.h:1394

jl_toplevel_eval_flex at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\toplevel.c:569

jl_parse_eval_all at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\ast.c:708

jl_load at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\toplevel.c:598

include_from_node1 at .\loading.jl:426

unknown function (ip: 0000000061C5EBE1)

jl_call_method_internal at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\julia_internal.h:175

macro expansion; at C:\Users\Andy\.julia\v0.5\StaticArrays\test\runtests.jl:18

unknown function (ip: 0000000013C047E3)

jl_call_method_internal at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\julia_internal.h:175

jl_parse_eval_all at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\ast.c:708

jl_load at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\toplevel.c:598

include_from_node1 at .\loading.jl:426

unknown function (ip: 0000000061C5EBE1)

jl_call_method_internal at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\julia_internal.h:175

process_options at .\client.jl:266

_start at .\client.jl:322

unknown function (ip: 0000000061C884CE)

jl_call_method_internal at /home/Administrator/buildbot/slave/package_win6_2-x64/build/src/home/Administrator/buildbot/slave/package_win6_2-x64/build/src\julia_internal.h:175

jl_apply at /home/Administrator/buildbot/slave/package_win6_2-x64/build/ui/../src\julia.h:1394

wmain at /home/Administrator/buildbot/slave/package_win6_2-x64/build/ui\repl.c:232

__tmainCRTStartup at /usr/src/debug/mingw64-x86_64-runtime-4.0.6-1/crt\crtexe.c:329

mainCRTStartup at /usr/src/debug/mingw64-x86_64-runtime-4.0.6-1/crt\crtexe.c:212

unknown function (ip: 00007FFF55158101)

unknown function (ip: 00007FFF5553C5B3)

ErrorException("type inference data-flow error: tried to double infer a function")

[Jameson Nash]

Looks like a bug, since the system really isn't supposed to do that, even if  your `@pure` function is broken (which it sounds like may be the case from your description, since `similar_type` doesn't sound like a generally valid operation to me). Please file a issue.