compiler/rustc_builtin_macros/src/panic.rs

   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::symbol::sym;
   6 use rustc_span::Span;
   7
   8 // This expands to either
   9 // - `$crate::panic::panic_2015!(...)` or
  10 // - `$crate::panic::panic_2021!(...)`
  11 // depending on the edition.
  12 //
  13 // This is used for both std::panic!() and core::panic!().
  14 //
  15 // `$crate` will refer to either the `std` or `core` crate depending on which
  16 // one we're expanding from.
  17 pub fn expand_panic<'cx>(
  18     cx: &'cx mut ExtCtxt<'_>,
  19     sp: Span,
  20     tts: TokenStream,
  21 ) -> Box<dyn MacResult + 'cx> {
  22     let panic = if sp.rust_2021() { sym::panic_2021 } else { sym::panic_2015 };
  23
  24     let sp = cx.with_call_site_ctxt(sp);
  25
  26     MacEager::expr(
  27         cx.expr(
  28             sp,
  29             ExprKind::MacCall(MacCall {
  30                 path: Path {
  31                     span: sp,
  32                     segments: cx
  33                         .std_path(&[sym::panic, panic])
  34                         .into_iter()
  35                         .map(|ident| PathSegment::from_ident(ident))
  36                         .collect(),
  37                     tokens: None,
  38                 },
  39                 args: P(MacArgs::Delimited(
  40                     DelimSpan::from_single(sp),
  41                     MacDelimiter::Parenthesis,
  42                     tts,
  43                 )),
  44                 prior_type_ascription: None,
  45             }),
  46         ),
  47     )
  48 }