From b9b4f549a45ccd6d5b5806153154c86e71e34bde Mon Sep 17 00:00:00 2001 From: Fabian Wolff Date: Sun, 28 Nov 2021 23:10:37 +0100 Subject: Add a suggestion if `macro_rules` is misspelled --- compiler/rustc_parse/src/parser/item.rs | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-) (limited to 'compiler/rustc_parse/src/parser') diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs index 24a8df49ac7..aa572eaf162 100644 --- a/compiler/rustc_parse/src/parser/item.rs +++ b/compiler/rustc_parse/src/parser/item.rs @@ -15,6 +15,7 @@ use rustc_ast::{MacArgs, MacCall, MacDelimiter}; use rustc_ast_pretty::pprust; use rustc_errors::{struct_span_err, Applicability, PResult, StashKey}; use rustc_span::edition::{Edition, LATEST_STABLE_EDITION}; +use rustc_span::lev_distance::lev_distance; use rustc_span::source_map::{self, Span}; use rustc_span::symbol::{kw, sym, Ident, Symbol}; @@ -407,10 +408,30 @@ impl<'a> Parser<'a> { fn parse_item_macro(&mut self, vis: &Visibility) -> PResult<'a, MacCall> { let path = self.parse_path(PathStyle::Mod)?; // `foo::bar` self.expect(&token::Not)?; // `!` - let args = self.parse_mac_args()?; // `( .. )` or `[ .. ]` (followed by `;`), or `{ .. }`. - self.eat_semi_for_macro_if_needed(&args); - self.complain_if_pub_macro(vis, false); - Ok(MacCall { path, args, prior_type_ascription: self.last_type_ascription }) + match self.parse_mac_args() { + // `( .. )` or `[ .. ]` (followed by `;`), or `{ .. }`. + Ok(args) => { + self.eat_semi_for_macro_if_needed(&args); + self.complain_if_pub_macro(vis, false); + Ok(MacCall { path, args, prior_type_ascription: self.last_type_ascription }) + } + + Err(mut err) => { + // Maybe the user misspelled `macro_rules` (issue #91227) + if self.token.is_ident() + && path.segments.len() == 1 + && lev_distance("macro_rules", &path.segments[0].ident.to_string()) <= 3 + { + err.span_suggestion( + path.span, + "perhaps you meant to define a macro", + "macro_rules".to_string(), + Applicability::MachineApplicable, + ); + } + Err(err) + } + } } /// Recover if we parsed attributes and expected an item but there was none. -- cgit 1.4.1-3-g733a5