From fa9d2230a65689289f64c897ad30c83251762320 Mon Sep 17 00:00:00 2001 From: "Felix S. Klock II" Date: Thu, 5 Feb 2015 16:02:22 +0100 Subject: make codemap more robust in face of ill-formed spans. This can be considered partial work on #8256. The main observable change: macro expansion sometimes results in spans where `lo > hi`; so for now, when we have such a span, do not attempt to return a snippet result. (Longer term, we might think about whether we could still present a snippet for the cases where this arises, e.g. perhaps by showing the whole macro as the snippet, assuming that is the sole cause of such spans; or by somehow looking up the closest AST node that holds both `lo` and `hi`, and showing that.) As a drive-by, revised the API to return a `Result` rather than an `Option`, with better information-packed error value that should help us (and maybe also our users) identify the causes of such problems in the future. Ideally the call-sites that really want an actual snippet would be updated to catch the newly added `Err` case and print something meaningful about it, but that is not part of this PR. --- src/libsyntax/parse/mod.rs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'src/libsyntax/parse') diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs index 6ff5c77f507..9e9ec08da03 100644 --- a/src/libsyntax/parse/mod.rs +++ b/src/libsyntax/parse/mod.rs @@ -1233,8 +1233,8 @@ mod test { let span = tts.iter().rev().next().unwrap().get_span(); match sess.span_diagnostic.cm.span_to_snippet(span) { - Some(s) => assert_eq!(&s[], "{ body }"), - None => panic!("could not get snippet"), + Ok(s) => assert_eq!(&s[], "{ body }"), + Err(_) => panic!("could not get snippet"), } } } -- cgit 1.4.1-3-g733a5