compiler/rustc_middle/src/util/bug.rs

   1 // These functions are used by macro expansion for bug! and span_bug!
   2
   3 use crate::ty::{tls, TyCtxt};
   4 use rustc_span::{MultiSpan, Span};
   5 use std::fmt;
   6 use std::panic::Location;
   7
   8 #[cold]
   9 #[inline(never)]
  10 #[track_caller]
  11 pub fn bug_fmt(args: fmt::Arguments<'_>) -> ! {
  12     // this wrapper mostly exists so I don't have to write a fully
  13     // qualified path of None::<Span> inside the bug!() macro definition
  14     opt_span_bug_fmt(None::<Span>, args, Location::caller());
  15 }
  16
  17 #[cold]
  18 #[inline(never)]
  19 #[track_caller]
  20 pub fn span_bug_fmt<S: Into<MultiSpan>>(span: S, args: fmt::Arguments<'_>) -> ! {
  21     opt_span_bug_fmt(Some(span), args, Location::caller());
  22 }
  23
  24 fn opt_span_bug_fmt<S: Into<MultiSpan>>(
  25     span: Option<S>,
  26     args: fmt::Arguments<'_>,
  27     location: &Location<'_>,
  28 ) -> ! {
  29     tls::with_opt(move |tcx| {
  30         let msg = format!("{}: {}", location, args);
  31         match (tcx, span) {
  32             (Some(tcx), Some(span)) => tcx.sess.diagnostic().span_bug(span, &msg),
  33             (Some(tcx), None) => tcx.sess.diagnostic().bug(&msg),
  34             (None, _) => panic!(msg),
  35         }
  36     });
  37     unreachable!();
  38 }
  39
  40 /// A query to trigger a `delay_span_bug`. Clearly, if one has a `tcx` one can already trigger a
  41 /// `delay_span_bug`, so what is the point of this? It exists to help us test `delay_span_bug`'s
  42 /// interactions with the query system and incremental.
  43 pub fn trigger_delay_span_bug(tcx: TyCtxt<'_>, key: rustc_hir::def_id::DefId) {
  44     tcx.sess.delay_span_bug(
  45         tcx.def_span(key),
  46         "delayed span bug triggered by #[rustc_error(delay_span_bug_from_inside_query)]",
  47     );
  48 }
  49
  50 pub fn provide(providers: &mut crate::ty::query::Providers) {
  51     *providers = crate::ty::query::Providers { trigger_delay_span_bug, ..*providers };
  52 }