cargo build fails 1.13.0. "multiple build targets"

[agmcleod]

Updating an older project of mine: https://github.com/agmcleod/tiled-loader-rs to compile with the latest. Clippy warnings are all passing now (via nightly), but with 1.13 im getting a panic when compiling with cargo build

RUST_BACKTRACE=1 cargo build
warning: file found to be present in multiple build targets: /Users/aaronmcleod/src/rust/tiled-loader-rs/examples/loadtmx.rs
   Compiling tiled v0.1.0 (file:///Users/aaronmcleod/src/rust/tiled-loader-rs)
error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: run with `RUST_BACKTRACE=1` for a backtrace

thread 'rustc' panicked at 'index out of bounds: the len is 13051 but the index is 13051', ../src/libserialize/leb128.rs:46
stack backtrace:
   1:        0x1077ed138 - std::sys::backtrace::tracing::imp::write::h6f1d53a70916b90d
   2:        0x1077fa8ff - std::panicking::default_hook::{{closure}}::h137e876f7d3b5850
   3:        0x1077f7dad - std::panicking::default_hook::h0ac3811ec7cee78c
   4:        0x1077f8446 - std::panicking::rust_panic_with_hook::hc303199e04562edf
   5:        0x1077f82e4 - std::panicking::begin_panic::h6ed03353807cf54d
   6:        0x1077f8202 - std::panicking::begin_panic_fmt::hc321cece241bb2f5
   7:        0x1077f8167 - rust_begin_unwind
   8:        0x1078385c0 - core::panicking::panic_fmt::h27224b181f9f037f
   9:        0x107838538 - core::panicking::panic_bounds_check::h19e9bbc59320a57e
  10:        0x107756a33 - <serialize::opaque::Decoder<'a> as serialize::serialize::Decoder>::read_usize::hdb6b9929c2878103
  11:        0x1041e77c7 - rustc_metadata::decoder::<impl rustc_metadata::cstore::MetadataBlob>::get_root::ha0bece0640a71bb4
  12:        0x10420efca - rustc_metadata::loader::Context::extract_one::h893f537a80fcaa7b
  13:        0x10420cd02 - rustc_metadata::loader::Context::find_library_crate::h0ae9ebab39601e07
  14:        0x1041fbebb - rustc_metadata::creader::CrateReader::load::hbbb9048f37b5929d
  15:        0x1041fb39c - rustc_metadata::creader::CrateReader::resolve_crate::h0ea8ce3f005d5018
  16:        0x104217fbd - rustc_metadata::creader::CrateReader::resolve_crate_deps::{{closure}}::hba6352ef73c55dfc
  17:        0x10418c690 - <std::collections::hash::map::HashMap<K, V, S> as core::iter::traits::FromIterator<(K, V)>>::from_iter::hfdd794029d934f9e
  18:        0x1041f9705 - rustc_metadata::creader::CrateReader::register_crate::h5c79c40329468538
  19:        0x1041fb65a - rustc_metadata::creader::CrateReader::resolve_crate::h0ea8ce3f005d5018
  20:        0x104203513 - <rustc_metadata::creader::CrateLoader<'a> as rustc::middle::cstore::CrateLoader>::process_item::h2c1f1f8ea009fc17
  21:        0x104379a0a - <rustc_resolve::build_reduced_graph::BuildReducedGraphVisitor<'a, 'b> as syntax::visit::Visitor>::visit_item::hca6f65f5d1f072d8
  22:        0x104378b8e - rustc_resolve::build_reduced_graph::<impl rustc_resolve::Resolver<'b>>::build_reduced_graph::h394847c4f1568da6
  23:        0x103c8779c - rustc_driver::driver::phase_2_configure_and_expand::{{closure}}::hdfad824fa7e49709
  24:        0x103c4077c - rustc_driver::driver::phase_2_configure_and_expand::h2f62e5b496da5c2b
  25:        0x103c391a2 - rustc_driver::driver::compile_input::hef221f9f618e92f5
  26:        0x103c62848 - rustc_driver::run_compiler::h7dddd4089f8330b4
  27:        0x103ba4340 - std::panicking::try::do_call::h1e3ece12e3f812df
  28:        0x1077faeba - __rust_maybe_catch_panic
  29:        0x103bc3004 - <F as alloc::boxed::FnBox<A>>::call_box::h05b222e46803eb30
  30:        0x1077f7064 - std::sys::thread::Thread::new::thread_start::h759e10bc4abc7e72
  31:     0x7fff98183aaa - _pthread_body
  32:     0x7fff981839f6 - _pthread_start

error: Could not compile `tiled`.

[alexcrichton]

Is this on a clean build directory? This looks like #37803 which was fixed recently

[agmcleod]

@alexcrichton that is definitely the case. Did a clean, and a build succeeded after. Sorry about that, thanks for the help :)