Expected type panic in parsing array type

[leonardo-m]

fn foo(a: [0; 1]) {}
fn main() {}

nightly-x86_64-pc-windows-gnu, rustc 1.17.0-nightly (ea7a648 2017-02-04)

error: expected type, found `0`
 --> test.rs:1:12
  |
1 | fn foo(a: [0; 1]) {}
  |            ^


error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.

thread 'rustc' panicked at 'internal error: entered unreachable code', C:\bot\slave\nightly-dist-rustc-win-gnu-64\build\src\libsyntax\parse\parser.rs:2649

[petrochenkov]

Stable -> beta regression.

[estebank]

Seems like it might have been introduced in #39118.

Cc @jseyfried

[jseyfried]

Fixed in #39674.