'could not find method while translating' while using macros

[indefini]

Platform:
Archlinux x86_64
rustc 0.11.0-pre (4462687 2014-05-23 16:31:20 -0700)
host: x86_64-unknown-linux-gnu

While using macros, I got this error:

error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug.
task 'rustc' failed at 'could not find method while translating', /home/chris/pkg/rust-git/src/rust/src/libstd/option.rs:167

Here is the code, let me know if you prefer a backtrace:

#![feature(macro_rules)]

macro_rules! new_test(
  ($member:ident, String) => (
    self.$member.to_owned()
    );
  ($member:ident, Struct) => (
    self.$member.clone()
    );
  ($member:ident, $yep:expr) => (
    self.$member
    )
  )

macro_rules! new_test_set(
  ($member:ident, String) => (
    match value {
      &String(ref s) => {
        self.$member = s.to_owned()
      }
      _ => {
        println!("cant set {:?} to {}, because it is a String", value, name);
      }
    }
    );
  ($member:ident, Struct) => (
    match value {
      &Struct(ref s) => {
        for p in s.fields().iter() {
          self.$member.set_property(
            p.as_slice(),
            & s.get_property(p.as_slice()));
        }
      }
      _ => {
        println!("cant set {:?} to {}, because it is a Struct", value, name);
      }
    }
    );
  ($member:ident, $yep:ident) => (
    match value {
      &$yep(f) => {
        self.$member = f;
      }
      _ => {
        println!("cant set {:?} to {}, because it is a {}", value, name, stringify!($yep));
      }
    }
    )
  )

macro_rules! property_impl(
  ($my_type:ty, [ $($member:ident,$mytype:ident)|+ ]) => (

    impl Property for $my_type
    {
      fn fields(&self) -> Vec<StrBuf>
        {
          return vec!( 
          $(
            stringify!($member).to_owned(),
            )+
          );
        }

        fn get_property(&self, name: &str) -> PropertyType
        {
          $(
            if name == stringify!($member)
            {
              return $mytype(new_test!($member, $mytype))
            }
           )+
          else {
            Float(0.0)
          }
        }

        fn set_property(&mut self, name: &str, value: &PropertyType)
        {
          $(
            if name == stringify!($member)
            {
              new_test_set!($member, $mytype)
              return;
            }
           )+
        }
    }
  );
)


#[deriving(Clone)]
pub struct Vec3
{
  x : f64,
  y : f64,
  z : f64
}

#[deriving(Clone)]
pub struct Quat
{
  x : f64,
  y : f64,
  z : f64,
  w : f64,
  t : i32,
  v : Box<Vec3>,
  txt : StrBuf
}

property_impl!(Vec3, [x,Float|y,Float|z,Float])

// Change this line to avoid the bug
//property_impl!(Quat, [x,Float|y,Float|z,Float|t,Int|txt,String])
property_impl!(Quat, [x,Float|y,Float|z,Float|t,Int|txt,String|v,Struct])

enum PropertyType {
  Int(i32),
  Float(f64),
  String(StrBuf),
  Struct(Box<Property>),
}

trait Property {
  fn fields(&self) -> Vec<StrBuf>;
  fn get_property(&self, name: &str) -> PropertyType;
  fn set_property(&mut self, name: &str, value: &PropertyType);
}

fn main() {

  let q = Quat{x:1.0, y:999.0, z:22.0, w:123.0,t:44,v:box Vec3{x:4.0,y:6.7,z:8.9}, txt:"test".to_owned()};
  println!(" quat {:?} ", q.get_property("z"));

}

[huonw]

Thanks for the report!

I reduced it to the following (with the assistance of creduce):

impl Property for Vec3 {
    fn get_property(&self, _: &str) -> PropertyType { Float(0.0) }
}
impl Property for Quat {
    fn get_property(&self, _: &str) -> PropertyType { Struct(self.v.clone()) }
}
#[deriving(Clone)]
struct Vec3;
struct Quat {
    v: Box<Vec3>,
}
enum PropertyType { Float(f64), Struct(Box<Property>), }
trait Property {
    fn get_property(&self, &str) -> PropertyType;
}

fn main() { }

reduce.rs:9:1: 11:2 warning: code is never used: `Quat`, #[warn(dead_code)] on by default
reduce.rs:9 struct Quat {
reduce.rs:10     v: Box<Vec3>,
reduce.rs:11 }
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
task 'rustc' failed at 'could not find method while translating', /home/rustbuild/src/rust-buildbot/slave/nightly-linux/build/src/libstd/option.rs:167
stack backtrace:
   1:     0x7fbe8942aed0 - rt::backtrace::imp::write::h829de4821815e280PUy::v0.11.0.pre
   2:     0x7fbe893a7c50 - rt::unwind::begin_unwind_inner::h3c95a01106a60df1Xuy::v0.11.0.pre
   3:     0x7fbe89e9b250 - rt::unwind::begin_unwind::h8363202580871814802::v0.11.0.pre
   4:     0x7fbe89fe8790 - middle::trans::meth::method_with_name::h27fe9715defde429xnv::v0.11.0.pre
   5:     0x7fbe89f1c610 - middle::trans::meth::trans_method_callee::he0d18bd58a692f20t8u::v0.11.0.pre
   6:     0x7fbe89f1c5a0 - middle::trans::callee::trans_method_call::closure.58859
   7:     0x7fbe89f1a0e0 - middle::trans::callee::trans_call_inner::h6ec9e97b2f0cf3a9xId::v0.11.0.pre
   8:     0x7fbe89f1bef0 - middle::trans::callee::trans_method_call::hb058dc63facf7471NDd::v0.11.0.pre
   9:     0x7fbe89f24c30 - middle::trans::expr::trans_rvalue_dps_unadjusted::hea9eb494db080d538hf::v0.11.0.pre
  10:     0x7fbe89ee5430 - middle::trans::expr::trans_into::h15e286d35b829d1fgse::v0.11.0.pre
  11:     0x7fbe89ee59e0 - middle::trans::controlflow::trans_block::h7d3f8bec55eca940I7a::v0.11.0.pre
  12:     0x7fbe89f24c30 - middle::trans::expr::trans_rvalue_dps_unadjusted::hea9eb494db080d538hf::v0.11.0.pre
  13:     0x7fbe89ee5430 - middle::trans::expr::trans_into::h15e286d35b829d1fgse::v0.11.0.pre
  14:     0x7fbe89f31a40 - middle::trans::expr::trans_uniq_expr::hbc1817203acccbdah3f::v0.11.0.pre
  15:     0x7fbe89f325b0 - middle::trans::expr::trans_unary::hca6bb9d2119494eeLXf::v0.11.0.pre
  16:     0x7fbe89f23b00 - middle::trans::expr::trans_unadjusted::ha9f4b115887b34acmPe::v0.11.0.pre
  17:     0x7fbe89ee5430 - middle::trans::expr::trans_into::h15e286d35b829d1fgse::v0.11.0.pre
  18:     0x7fbe89ee59e0 - middle::trans::controlflow::trans_block::h7d3f8bec55eca940I7a::v0.11.0.pre
  19:     0x7fbe89fa2a70 - middle::trans::base::trans_closure::h247c5303be3eb095Php::v0.11.0.pre
  20:     0x7fbe89eae960 - middle::trans::base::trans_fn::hac7f31459ea86cc45pp::v0.11.0.pre
  21:     0x7fbe89eaee60 - middle::trans::monomorphize::monomorphic_fn::h29e7539c7e7490a1Lka::v0.11.0.pre
  22:     0x7fbe89f0fb10 - middle::trans::callee::trans_fn_ref_with_vtables::h739a9d33fff1d6b8Kjd::v0.11.0.pre
  23:     0x7fbe89f0b2f0 - middle::trans::callee::trans_fn_ref::hf912bb2e1b25d34aScd::v0.11.0.pre
  24:     0x7fbe89f1c610 - middle::trans::meth::trans_method_callee::he0d18bd58a692f20t8u::v0.11.0.pre
  25:     0x7fbe89f1c5a0 - middle::trans::callee::trans_method_call::closure.58859
  26:     0x7fbe89f1a0e0 - middle::trans::callee::trans_call_inner::h6ec9e97b2f0cf3a9xId::v0.11.0.pre
  27:     0x7fbe89f1bef0 - middle::trans::callee::trans_method_call::hb058dc63facf7471NDd::v0.11.0.pre
  28:     0x7fbe89f24c30 - middle::trans::expr::trans_rvalue_dps_unadjusted::hea9eb494db080d538hf::v0.11.0.pre
  29:     0x7fbe89f23b00 - middle::trans::expr::trans_unadjusted::ha9f4b115887b34acmPe::v0.11.0.pre
  30:     0x7fbe89ee7720 - middle::trans::expr::trans::h31b1d37217a231c6cwe::v0.11.0.pre
  31:     0x7fbe89f1deb0 - middle::trans::callee::trans_args::h79811d38aa6e67c3N2d::v0.11.0.pre
  32:     0x7fbe89f1a0e0 - middle::trans::callee::trans_call_inner::h6ec9e97b2f0cf3a9xId::v0.11.0.pre
  33:     0x7fbe89f19eb0 - middle::trans::callee::trans_call::h16885ad67fa12e03FCd::v0.11.0.pre
  34:     0x7fbe89f24c30 - middle::trans::expr::trans_rvalue_dps_unadjusted::hea9eb494db080d538hf::v0.11.0.pre
  35:     0x7fbe89ee5430 - middle::trans::expr::trans_into::h15e286d35b829d1fgse::v0.11.0.pre
  36:     0x7fbe89ee59e0 - middle::trans::controlflow::trans_block::h7d3f8bec55eca940I7a::v0.11.0.pre
  37:     0x7fbe89fa2a70 - middle::trans::base::trans_closure::h247c5303be3eb095Php::v0.11.0.pre
  38:     0x7fbe89eae960 - middle::trans::base::trans_fn::hac7f31459ea86cc45pp::v0.11.0.pre
  39:     0x7fbe89fa6c40 - middle::trans::meth::trans_impl::hcad0b0d6fab6bc8cX3u::v0.11.0.pre
  40:     0x7fbe89ea91a0 - middle::trans::base::trans_item::h62a895b39c0cb8ccCBp::v0.11.0.pre
  41:     0x7fbe89fb11f0 - middle::trans::base::trans_crate::h3026657c475a7720poq::v0.11.0.pre
  42:     0x7fbe8a76cd30 - driver::driver::phase_4_translate_to_llvm::h639e7dc77f10a518H1j::v0.11.0.pre
  43:     0x7fbe8a762000 - driver::driver::compile_input::hc7e76cb3959dc3aeiJj::v0.11.0.pre
  44:     0x7fbe8a82d820 - driver::run_compiler::ha4687608fe641c15bmm::v0.11.0.pre
  45:     0x7fbe8a82d740 - driver::main_args::closure.93513
  46:     0x7fbe8a842a20 - driver::monitor::closure.94585
  47:     0x7fbe8a83dd10 - task::TaskBuilder::try::closure.94348
  48:     0x7fbe899495a0 - task::spawn_opts::closure.7809
  49:     0x7fbe89425050 - rt::task::Task::run::closure.25264
  50:     0x7fbe89489b10 - rust_try
  51:     0x7fbe89424fa0 - rt::task::Task::run::h82b2a3f233cfc4a9Ajw::v0.11.0.pre
  52:     0x7fbe89949350 - task::spawn_opts::closure.7782
  53:     0x7fbe894292d0 - rt::thread::thread_start::he85cc53b3abeddd182w::v0.11.0.pre
  54:     0x7fbe86ecdfa0 - start_thread
  55:     0x7fbe89070a09 - __clone
  56:                0x0 - <unknown>

[huonw]

Ah! But it works with an explicit cast to the trait object:

fn get_property(&self, _: &str) -> PropertyType { Struct(self.v.clone() as Box<Property>) }

i.e. it seems to be problem with implicit trait object coercions. cc @luqmana

(This has the same error message as #6334 but the causes don't look the same.)

[luqmana]

The reason for this seems to be because in typeck::check::vtable::early_resolve_expr we first encounter the method call expr (self.v.clone() in this code) and lookup the vtables for it which we then insert into the vtable_map. The key for this map (essentially) being the expression's NodeId. (It's actually a struct containing the expression id and how many times to deref) Then we go on to check if there are any adjustments for the current expression. In this case there is, since we can coerce to a trait object here. So then go on to lookup vtables for the adjusted expression and once again we insert it into the vtable_map. The problem is that we use the same key, and thus we overwrite the entry from earlier. We don't run into this if you use an explicit cast since the method call and the cast would be 2 expressions we consider separately and thus no clash.