From aaec60836761da35a8d0cf6179769eb9bc9f63c3 Mon Sep 17 00:00:00 2001 From: Esteban Küber Date: Thu, 1 Feb 2018 11:51:49 -0800 Subject: Minimize weird spans involving macro context Sometimes the parser attempts to synthesize spans from within a macro context with the span for the captured argument, leading to non-sensical spans with very bad output. Given that an incorrect span is worse than a partially incomplete span, when detecting this situation return only one of the spans without mergin them. --- src/libsyntax_pos/lib.rs | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) (limited to 'src/libsyntax_pos') diff --git a/src/libsyntax_pos/lib.rs b/src/libsyntax_pos/lib.rs index 85f0925b982..09e2677eed6 100644 --- a/src/libsyntax_pos/lib.rs +++ b/src/libsyntax_pos/lib.rs @@ -361,13 +361,24 @@ impl Span { /// Return a `Span` that would enclose both `self` and `end`. pub fn to(self, end: Span) -> Span { - let span = self.data(); - let end = end.data(); + let span_data = self.data(); + let end_data = end.data(); + // FIXME(jseyfried): self.ctxt should always equal end.ctxt here (c.f. issue #23480) + // Return the macro span on its own to avoid weird diagnostic output. It is preferable to + // have an incomplete span than a completely nonsensical one. + if span_data.ctxt != end_data.ctxt { + if span_data.ctxt == SyntaxContext::empty() { + return end; + } else if end_data.ctxt == SyntaxContext::empty() { + return self; + } + // both span fall within a macro + // FIXME(estebank) check if it is the *same* macro + } Span::new( - cmp::min(span.lo, end.lo), - cmp::max(span.hi, end.hi), - // FIXME(jseyfried): self.ctxt should always equal end.ctxt here (c.f. issue #23480) - if span.ctxt == SyntaxContext::empty() { end.ctxt } else { span.ctxt }, + cmp::min(span_data.lo, end_data.lo), + cmp::max(span_data.hi, end_data.hi), + if span_data.ctxt == SyntaxContext::empty() { end_data.ctxt } else { span_data.ctxt }, ) } -- cgit 1.4.1-3-g733a5