From 539242a07b15ec95aa196bfa4c18f6a8b01b8ecb Mon Sep 17 00:00:00 2001 From: Yuki Okushi Date: Thu, 1 Apr 2021 08:37:29 +0900 Subject: Add a suggestion when using a type alias instead of trait alias --- compiler/rustc_resolve/src/late/diagnostics.rs | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'compiler/rustc_resolve/src') diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs index 1fb07bdae9d..0314de9ebbe 100644 --- a/compiler/rustc_resolve/src/late/diagnostics.rs +++ b/compiler/rustc_resolve/src/late/diagnostics.rs @@ -928,7 +928,14 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> { let msg = "you might have meant to use `#![feature(trait_alias)]` instead of a \ `type` alias"; if let Some(span) = self.def_span(def_id) { - err.span_help(span, msg); + if let Ok(snip) = self.r.session.source_map().span_to_snippet(span) { + // The span contains a type alias so we should be able to + // replace `type` with `trait`. + let snip = snip.replacen("type", "trait", 1); + err.span_suggestion(span, msg, snip, Applicability::MaybeIncorrect); + } else { + err.span_help(span, msg); + } } else { err.help(msg); } -- cgit 1.4.1-3-g733a5