1 use rustc_ast::ptr::P;
2 use rustc_ast::tokenstream::{DelimSpan, TokenStream};
3 use rustc_ast::*;
4 use rustc_expand::base::*;
5 use rustc_span::edition::Edition;
6 use rustc_span::symbol::sym;
7 use rustc_span::Span;
8
9 // This expands to either
10 // - `$crate::panic::panic_2015!(...)` or
11 // - `$crate::panic::panic_2021!(...)`
12 // depending on the edition.
13 //
14 // This is used for both std::panic!() and core::panic!().
15 //
16 // `$crate` will refer to either the `std` or `core` crate depending on which
17 // one we're expanding from.
expand_panic<'cx>( cx: &'cx mut ExtCtxt<'_>, sp: Span, tts: TokenStream, ) -> Box<dyn MacResult + 'cx>18 pub fn expand_panic<'cx>(
19 cx: &'cx mut ExtCtxt<'_>,
20 sp: Span,
21 tts: TokenStream,
22 ) -> Box<dyn MacResult + 'cx> {
23 let panic = if use_panic_2021(sp) { sym::panic_2021 } else { sym::panic_2015 };
24
25 let sp = cx.with_call_site_ctxt(sp);
26
27 MacEager::expr(
28 cx.expr(
29 sp,
30 ExprKind::MacCall(MacCall {
31 path: Path {
32 span: sp,
33 segments: cx
34 .std_path(&[sym::panic, panic])
35 .into_iter()
36 .map(|ident| PathSegment::from_ident(ident))
37 .collect(),
38 tokens: None,
39 },
40 args: P(MacArgs::Delimited(
41 DelimSpan::from_single(sp),
42 MacDelimiter::Parenthesis,
43 tts,
44 )),
45 prior_type_ascription: None,
46 }),
47 ),
48 )
49 }
50
use_panic_2021(mut span: Span) -> bool51 pub fn use_panic_2021(mut span: Span) -> bool {
52 // To determine the editon, we check the first span up the expansion
53 // stack that does not have #[allow_internal_unstable(edition_panic)].
54 // (To avoid using the edition of e.g. the assert!() or debug_assert!() definition.)
55 loop {
56 let expn = span.ctxt().outer_expn_data();
57 if let Some(features) = expn.allow_internal_unstable {
58 if features.iter().any(|&f| f == sym::edition_panic) {
59 span = expn.call_site;
60 continue;
61 }
62 }
63 break expn.edition >= Edition::Edition2021;
64 }
65 }
66