ICE on nightly: src/librustc_typeck/check/mod.rs:2015: no type for node

[lwe]

When trying to use modules (while learning rust at RustBridge, thanks for RustFest/RöstiFest ZH), I run into an internal compiler error that used Hmac + SHA256, when placing the use statements in the wrong place.

I tried this code:

extern crate sha2;
extern crate hmac;
extern crate base64;

// Placing the use here is actually a compile error on Rust stable, with
// a fine error message. Moving it to the right place (i.e. inside mod foo) it
// works properly and gives the right error message and not an internal compiler error
use hmac::{Hmac, Mac};
use sha2::Sha256;
use base64::encode;

mod foo {
    pub fn hmac256(input: String, secret: &[u8]) -> String {
        let mut mac = Hmac::<Sha256>::new(secret);
        mac.input(input.as_bytes());
        let result = mac.result();
        let bytes = result.code();

        encode(bytes)
    }
}

I expected to see this happen:

error[E0433]: failed to resolve. Use of undeclared type or module `Hmac`
  --> src/lib.rs:12:23
   |
12 |         let mut mac = Hmac::<Sha256>::new(secret);
   |                       ^^^^^^^^^^^^^^^^^^^ Use of undeclared type or module `Hmac`

error[E0433]: failed to resolve. Use of undeclared type or module `Hmac`
  --> src/lib.rs:12:23
   |
12 |         let mut mac = Hmac::<Sha256>::new(secret);
   |                       ^^^^^^^^^^^^^^^^^^^ Use of undeclared type or module `Hmac`

error[E0412]: cannot find type `Sha256` in this scope
  --> src/lib.rs:12:30
   |
12 |         let mut mac = Hmac::<Sha256>::new(secret);
   |                              ^^^^^^ not found in this scope
   |
help: possible candidate is found in another module, you can import it into scope
   |
9  | use sha2::Sha256;

...and more like these

error: aborting due to 3 previous errors

Instead, this happened:

error[E0433]: failed to resolve. Use of undeclared type or module `Hmac`
  --> src/lib.rs:12:23
   |
12 |         let mut mac = Hmac::<Sha256>::new(secret);
   |                       ^^^^ Use of undeclared type or module `Hmac`

error[E0433]: failed to resolve. Use of undeclared type or module `Hmac`
  --> src/lib.rs:12:23
   |
12 |         let mut mac = Hmac::<Sha256>::new(secret);
   |                       ^^^^ Use of undeclared type or module `Hmac`

error[E0412]: cannot find type `Sha256` in this scope
  --> src/lib.rs:12:30
   |
12 |         let mut mac = Hmac::<Sha256>::new(secret);
   |                              ^^^^^^ not found in this scope
   |
help: possible candidate is found in another module, you can import it into scope
   |
11 |     use sha2::Sha256;
   |

error[E0425]: cannot find function `encode` in this scope
  --> src/lib.rs:17:9
   |
17 |         encode(bytes)
   |         ^^^^^^ not found in this scope
   |
help: possible candidate is found in another module, you can import it into scope
   |
11 |     use base64::encode;
   |

warning: unused imports: `Hmac`, `Mac`
 --> src/lib.rs:5:12
  |
5 | use hmac::{Hmac, Mac};
  |            ^^^^  ^^^
  |
  = note: #[warn(unused_imports)] on by default

warning: unused import: `sha2::Sha256`
 --> src/lib.rs:6:5
  |
6 | use sha2::Sha256;
  |     ^^^^^^^^^^^^

warning: unused import: `base64::encode`
 --> src/lib.rs:7:5
  |
7 | use base64::encode;
  |     ^^^^^^^^^^^^^^

error[E0412]: cannot find type `Sha256` in this scope
  --> src/lib.rs:12:30
   |
12 |         let mut mac = Hmac::<Sha256>::new(secret);
   |                              ^^^^^^ not found in this scope
   |
help: possible candidate is found in another module, you can import it into scope
   |
11 |     use sha2::Sha256;
   |

error[E0425]: cannot find function `encode` in this scope
  --> src/lib.rs:17:9
   |
17 |         encode(bytes)
   |         ^^^^^^ not found in this scope
   |
help: possible candidate is found in another module, you can import it into scope
   |
11 |     use base64::encode;
   |

warning: unused imports: `Hmac`, `Mac`
 --> src/lib.rs:5:12
  |
5 | use hmac::{Hmac, Mac};
  |            ^^^^  ^^^
  |
  = note: #[warn(unused_imports)] on by default

warning: unused import: `sha2::Sha256`
 --> src/lib.rs:6:5
  |
6 | use sha2::Sha256;
  |     ^^^^^^^^^^^^

warning: unused import: `base64::encode`
 --> src/lib.rs:7:5
  |
7 | use base64::encode;
  |     ^^^^^^^^^^^^^^

error: internal compiler error: src/librustc_typeck/check/mod.rs:2015: no type for node 27: type Sha256 (id=27) in fcx 0x700007762468

error: internal compiler error: src/librustc_typeck/check/mod.rs:2015: no type for node 27: type Sha256 (id=27) in fcx 0x700005c7c468

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 1.22.0-nightly (6f87d20a7 2017-09-29) running on x86_64-apple-darwin

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:492:8
note: Run with `RUST_BACKTRACE=1` for a backtrace.

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 1.22.0-nightly (6f87d20a7 2017-09-29) running on x86_64-apple-darwin

Meta

rustc 1.22.0-nightly (6f87d20a7 2017-09-29)
binary: rustc
commit-hash: 6f87d20a7cce70b8cc59a1adf3037d14bc83f237
commit-date: 2017-09-29
host: x86_64-apple-darwin
release: 1.22.0-nightly
LLVM version: 4.0

[lwe]

This could be a duplicate of #44820 and #44814.

[petrochenkov]

Should be fixed in #44945