Panic when formatting

[ndmitchell]

Describe the bug

Given:

fn get_hashes() { x. 0. 0 }

I get:

thread 'main' panicked at 'bad span: `.`: ` 0`', src/tools/rustfmt/src/source_map.rs:52:13

To Reproduce

$ rustfmt test.rs
thread 'main' panicked at 'bad span: `.`: ` 0`', src/tools/rustfmt/src/source_map.rs:52:13
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Expected behavior

Not panic.

Meta

• rustfmt version: rustfmt 1.4.22-nightly (97d03010 2020-10-04)
• From where did you install rustfmt?: rustup
• How do you run rustfmt: rustfmt

[zgotsch]

I am also getting this error. Interestingly, the message is a bit different (and less helpful!) without the spaces before the 0s:

Input:

fn get_hashes() { x.0.0 }

Output:

thread 'main' panicked at 'bad span: `.`: ``', src/tools/rustfmt/src/source_map.rs:52:13
stack backtrace:
   0: _rust_begin_unwind
   1: std::panicking::begin_panic_fmt
   2: <rustfmt_nightly::visitor::SnippetProvider as rustfmt_nightly::source_map::SpanUtils>::span_before::{{closure}}
   3: rustfmt_nightly::chains::rewrite_chain
   4: rustfmt_nightly::expr::format_expr
   5: rustfmt_nightly::stmt::format_stmt
   6: rustfmt_nightly::visitor::FmtVisitor::walk_stmts
   7: rustfmt_nightly::visitor::FmtVisitor::visit_block
   8: rustfmt_nightly::visitor::FmtVisitor::visit_fn
   9: rustfmt_nightly::visitor::FmtVisitor::visit_item
  10: rustfmt_nightly::reorder::<impl rustfmt_nightly::visitor::FmtVisitor>::visit_items_with_reordering
  11: rustfmt_nightly::visitor::FmtVisitor::format_separate_mod
  12: rustfmt_nightly::formatting::format_project
  13: scoped_tls::ScopedKey<T>::set
  14: rustfmt_nightly::Session<T>::format
  15: rustfmt::format_and_emit_report
  16: rustfmt_nightly::Session<T>::override_config
  17: rustfmt::execute
  18: rustfmt::main

[calebcartwright]

Duplicate of #4355, resolved in the upcoming 1.4.23 release

edit - typo fix