Compiler Panicked when compiling tutorial application of safer_ffi

[okpatil4u]

While compiling safer_ffi tutorial example, I encountered following panic

Compiling proc-macro2 v1.0.24
   Compiling unicode-xid v0.2.1
   Compiling syn v1.0.54
   Compiling proc-macro-hack v0.5.19
   Compiling libc v0.2.81
   Compiling mini_paste-proc_macro v0.1.11
   Compiling mini_paste v0.1.11
   Compiling quote v1.0.7
   Compiling safer_ffi-proc_macro v0.0.5
   Compiling require_unsafe_in_body v0.2.1
   Compiling safer-ffi v0.0.5
   Compiling crate_name v0.1.0 (/Users/omkarpatil/experiments/samples/ffi/safe_ffi)
thread 'rustc' panicked at 'Expected module, found DefId(16:190)', compiler/rustc_metadata/src/rmeta/decoder.rs:1198:13
note: run with `RUST_BACKTRACE=1` environment variable to display 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/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.48.0 (7eac88abb 2020-11-16) running on x86_64-apple-darwin

note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental --crate-type staticlib

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

error: could not compile `crate_name`

[danielhenrymantilla]

Duplicate of #75982 (and #75957, #75987). The issue has been fixed in latest nightly, and I think that in latest beta too, sadly it hasn't yet landed on stable, we will have to wait for the nest stable release in January.

So the current workaround is to pin the compiler version to before the regression (1.46.0) or to after the fix (beta i.e., ≥ 1.49.0).