ICE: tuple_fields called on non-tuple

[lolgeny]

I was working on some procedural macros when I encountered

error: internal compiler error: compiler\rustc_middle\src\ty\sty.rs:2138:18: tuple_fields called on non-tuple

thread 'rustc' panicked at 'Box<Any>', compiler\rustc_errors\src\lib.rs:945:9
stack backtrace:
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.49.0-nightly (b1496c6e6 2020-10-18) running on x86_64-pc-windows-msvc

note: compiler flags: -Z macro-backtrace -C prefer-dynamic -C embed-bitcode=no -C debuginfo=2 -C incremental --crate-type proc-macro

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

note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
query stack during panic:

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

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.49.0-nightly (b1496c6e6 2020-10-18) running on x86_64-pc-windows-msvc

note: compiler flags: -Z macro-backtrace -C prefer-dynamic -C embed-bitcode=no -C debuginfo=2 -C incremental

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

query stack during panic:
#0 [typeck] type-checking `cache`
#0 [typeck] type-checking `cache`
#1 [typeck_item_bodies] type-checking all item bodies
#1 [typeck_item_bodies] type-checking all item bodies
#2 [analysis] running analysis passes on this crate
#2 [analysis] running analysis passes on this crate
end of query stack
end of query stack

I'm not sure what caused it, probably generated incorrect code. I'm using the latest nightly compiler.

[camelid]

I'm using the latest nightly compiler.

Hmm, the rustc output you posted says that you're running a nightly compiler that's two months out-of-date (2020-10-18). I think this issue was fixed after then. Can you try with a recent nightly (e.g. 2020-12-10) and let us know if it works? Thanks.

[camelid]

I think #77993 is the same underlying issue; it was fixed after the compiler version you're running.

[camelid]

@lolgeny Could you please try with a recent nightly (use rustup update nightly)?