From a73e44bce16c9610c5415db3037a69eef0df3c4e Mon Sep 17 00:00:00 2001 From: Pyrode Date: Thu, 27 Feb 2025 12:23:47 +0530 Subject: Provide helpful diagnostics for shebang lookalikes --- compiler/rustc_parse/src/parser/attr.rs | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'compiler/rustc_parse') diff --git a/compiler/rustc_parse/src/parser/attr.rs b/compiler/rustc_parse/src/parser/attr.rs index 066b570c23f..53614049f08 100644 --- a/compiler/rustc_parse/src/parser/attr.rs +++ b/compiler/rustc_parse/src/parser/attr.rs @@ -127,12 +127,29 @@ impl<'a> Parser<'a> { let lo = self.token.span; // Attributes can't have attributes of their own [Editor's note: not with that attitude] self.collect_tokens_no_attrs(|this| { + let pound_hi = this.token.span.hi(); assert!(this.eat(exp!(Pound)), "parse_attribute called in non-attribute position"); + let not_lo = this.token.span.lo(); let style = if this.eat(exp!(Bang)) { ast::AttrStyle::Inner } else { ast::AttrStyle::Outer }; - this.expect(exp!(OpenBracket))?; + let mut bracket_res = this.expect(exp!(OpenBracket)); + // If `#!` is not followed by `[` + if let Err(err) = &mut bracket_res + && style == ast::AttrStyle::Inner + && pound_hi == not_lo + { + err.note( + "the token sequence `#!` here looks like the start of \ + a shebang interpreter directive but it is not", + ); + err.help( + "if you meant this to be a shebang interpreter directive, \ + move it to the very start of the file", + ); + } + bracket_res?; let item = this.parse_attr_item(ForceCollect::No)?; this.expect(exp!(CloseBracket))?; let attr_sp = lo.to(this.prev_token.span); -- cgit 1.4.1-3-g733a5