Compiler crashes on invalid variable definition

[patrigg]

The compiler unexpectedly crashes when I try to compile a program with an ill-formed variable definition.

I tried this code:

use std::path::Path;

fn main() {
    let Path::new();
}

I expected to see this happen: Compilation error message telling me that the variable definition is ill-formed.

Instead, this happened: The compiler crashes with the following error.

Compiling XXXX v0.1.0 (C:\XXXX)
Running rustc --crate-name XXXX src\main.rs --color always --crate-type bin --emit=dep-info,link -C debuginfo=2 -C metadata=4bbcaaecf78792fe -C extra-filename=-4bbcaaecf78792fe --out-dir C:\Code\thingos\tools\thingos_pass\target\debug\deps -C incremental=C:\XXXX\target\debug\incremental -L dependency=C:\XXXX\target\debug\deps
thread 'main' panicked at 'expected fn type', libcore\option.rs:1000:5
note: Run with RUST_BACKTRACE=1 for a backtrace.

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: rustc 1.30.0 (da5f414 2018-10-24) running on x86_64-pc-windows-msvc

note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin

note: some of the compiler flags provided by cargo are hidden

error: Could not compile XXXX.

Caused by:
process didn't exit successfully: rustc --crate-name XXXX src\main.rs --color always --crate-type bin --emit=dep-info,link -C debuginfo=2 -C metadata=4bbcaaecf78792fe -C extra-filename=-4bbcaaecf78792fe --out-dir C:\XXXX\target\debug\deps -C incremental=C:\XXXX\target\debug\incremental -L dependency=C:\XXXX\target\debug\deps (exit code: 101)

Meta

rustc --version --verbose:

rustc 1.30.0 (da5f414 2018-10-24)
binary: rustc
commit-hash: da5f414
commit-date: 2018-10-24
host: x86_64-pc-windows-msvc
release: 1.30.0
LLVM version: 8.0

[estebank]

   8: core::panicking::panic_fmt
             at libcore/panicking.rs:77
   9: core::option::expect_failed
             at libcore/option.rs:1008
  10: rustc_typeck::check::_match::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx>>::check_pat_tuple_struct
  11: rustc_typeck::check::_match::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx>>::check_pat_walk
  12: rustc_typeck::check::FnCtxt::check_decl_local
  13: rustc_typeck::check::FnCtxt::check_block_with_expected
  14: rustc_typeck::check::FnCtxt::check_expr_kind
  15: rustc_typeck::check::FnCtxt::check_expr_with_expectation_and_needs
  16: rustc_typeck::check::FnCtxt::check_return_expr
  17: rustc_typeck::check::check_fn

rust/src/librustc_typeck/check/_match.rs

Line 819 in 451987d

let pat_ty = pat_ty.no_late_bound_regions().expect("expected fn type");