`check_fn` attempts to do span interpolation on a macro, ICE ensues

[estebank]

error: Could not compile `pretty_tests`.
warning: build failed, waiting for other jobs to finish...
thread 'rustc' panicked at 'begin <= end (599 <= 288) when slicing `pub)
            $(#[$derive])*
            struct $type_name;
            type PartialState = (());
            $(#[$attr])*
            fn $name [$($type_params)*]($($arg : $arg_type),*)($input_type) -> $output_type
                where [$($where_clause`[...]', src/libcore/str/mod.rs:2014:5
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
   1: std::sys_common::backtrace::_print
   2: std::panicking::default_hook::{{closure}}
   3: std::panicking::default_hook
   4: rustc::util::common::panic_hook
   5: std::panicking::rust_panic_with_hook
   6: std::panicking::continue_panic_fmt
   7: rust_begin_unwind
   8: core::panicking::panic_fmt
   9: core::str::slice_error_fail
  10: core::str::traits::<impl core::slice::SliceIndex<str> for core::ops::range::Range<usize>>::index::{{closure}}
  11: <clippy_lints::functions::Functions as rustc::lint::LateLintPass<'a, 'tcx>>::check_fn
  12: <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_fn
  13: rustc::hir::intravisit::walk_item
  14: <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_item
  15: <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_mod
  16: rustc::hir::intravisit::walk_item
  17: <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_item
  18: <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_mod
  19: rustc::hir::intravisit::walk_item
  20: <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_item
  21: <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_mod
  22: rustc::hir::intravisit::walk_crate
  23: rustc::lint::context::check_crate
  24: rustc_driver::driver::phase_3_run_analysis_passes::{{closure}}::{{closure}}
  25: rustc::util::common::time
  26: <std::thread::local::LocalKey<T>>::with
  27: rustc::ty::context::TyCtxt::create_and_enter
  28: rustc_driver::driver::compile_input
  29: rustc_driver::run_compiler_with_pool
  30: <scoped_tls::ScopedKey<T>>::set
  31: rustc_driver::run_compiler
  32: <scoped_tls::ScopedKey<T>>::set
  33: syntax::with_globals
  34: __rust_maybe_catch_panic
  35: <F as alloc::boxed::FnBox<A>>::call_box
  36: std::sys::unix::thread::Thread::new::thread_start
  37: _pthread_body
  38: _pthread_start
query stack during panic:
end of query stack

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 1.34.0-nightly (f66e4697a 2019-02-20) running on x86_64-apple-darwin

note: compiler flags: -C debuginfo=2 --crate-type lib

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

error: Could not compile `combine`.

I'm guessing this fails when trying to synthesize a suggestion, which could be avoided if accounting for macros.

[estebank]

I'll try to create a repro case later.

[martinsp]

I think this might be the same issue as #3747

[estebank]

@martinsp confirmed it's the same issue. Closing as dupe.