Aaron Hill b541d3da5d Add -Z span-debug to allow for easier debugging of proc macros ...

Currently, the `Debug` impl for `proc_macro::Span` just prints out
the byte range. This can make debugging proc macros (either as a crate
author or as a compiler developer) very frustrating, since neither the
actual filename nor the `SyntaxContext` is displayed.

This commit adds a perma-unstable flag `-Z span-debug`. When enabled,
the `Debug` impl for `proc_macro::Span` simply forwards directly to
`rustc_span::Span`. Once #72618 is merged, this will start displaying
actual line numbers.

While `Debug` impls are not subject to Rust's normal stability
guarnatees, we probably shouldn't expose any additional information on
stable until `#![feature(proc_macro_span)]` is stabilized. Otherwise,
we would be providing a 'backdoor' way to access information that's
supposed be behind unstable APIs.

2020-06-04 15:39:12 -04:00

..

auxiliary

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dump-debug-span-debug.rs

Add -Z span-debug to allow for easier debugging of proc macros

2020-06-04 15:39:12 -04:00

dump-debug-span-debug.stderr

Add -Z span-debug to allow for easier debugging of proc macros

2020-06-04 15:39:12 -04:00

dump-debug.rs

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dump-debug.stderr

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