compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs

   1 use crate::infer::lexical_region_resolve::RegionResolutionError;
   2 use crate::infer::lexical_region_resolve::RegionResolutionError::*;
   3 use crate::infer::InferCtxt;
   4 use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
   5 use rustc_middle::ty::{self, TyCtxt};
   6 use rustc_span::source_map::Span;
   7
   8 mod different_lifetimes;
   9 pub mod find_anon_type;
  10 mod mismatched_static_lifetime;
  11 mod named_anon_conflict;
  12 mod placeholder_error;
  13 mod static_impl_trait;
  14 mod trait_impl_difference;
  15 mod util;
  16
  17 pub use different_lifetimes::suggest_adding_lifetime_params;
  18 pub use find_anon_type::find_anon_type;
  19 pub use static_impl_trait::suggest_new_region_bound;
  20 pub use util::find_param_with_region;
  21
  22 impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
  23     pub fn try_report_nice_region_error(&self, error: &RegionResolutionError<'tcx>) -> bool {
  24         NiceRegionError::new(self, error.clone()).try_report().is_some()
  25     }
  26 }
  27
  28 pub struct NiceRegionError<'cx, 'tcx> {
  29     infcx: &'cx InferCtxt<'cx, 'tcx>,
  30     error: Option<RegionResolutionError<'tcx>>,
  31     regions: Option<(Span, ty::Region<'tcx>, ty::Region<'tcx>)>,
  32 }
  33
  34 impl<'cx, 'tcx> NiceRegionError<'cx, 'tcx> {
  35     pub fn new(infcx: &'cx InferCtxt<'cx, 'tcx>, error: RegionResolutionError<'tcx>) -> Self {
  36         Self { infcx, error: Some(error), regions: None }
  37     }
  38
  39     pub fn new_from_span(
  40         infcx: &'cx InferCtxt<'cx, 'tcx>,
  41         span: Span,
  42         sub: ty::Region<'tcx>,
  43         sup: ty::Region<'tcx>,
  44     ) -> Self {
  45         Self { infcx, error: None, regions: Some((span, sub, sup)) }
  46     }
  47
  48     fn tcx(&self) -> TyCtxt<'tcx> {
  49         self.infcx.tcx
  50     }
  51
  52     pub fn try_report_from_nll(&self) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
  53         // Due to the improved diagnostics returned by the MIR borrow checker, only a subset of
  54         // the nice region errors are required when running under the MIR borrow checker.
  55         self.try_report_named_anon_conflict().or_else(|| self.try_report_placeholder_conflict())
  56     }
  57
  58     pub fn try_report(&self) -> Option<ErrorGuaranteed> {
  59         self.try_report_from_nll()
  60             .map(|mut diag| diag.emit())
  61             .or_else(|| self.try_report_impl_not_conforming_to_trait())
  62             .or_else(|| self.try_report_anon_anon_conflict())
  63             .or_else(|| self.try_report_static_impl_trait())
  64             .or_else(|| self.try_report_mismatched_static_lifetime())
  65     }
  66
  67     pub(super) fn regions(&self) -> Option<(Span, ty::Region<'tcx>, ty::Region<'tcx>)> {
  68         match (&self.error, self.regions) {
  69             (Some(ConcreteFailure(origin, sub, sup)), None) => Some((origin.span(), *sub, *sup)),
  70             (Some(SubSupConflict(_, _, origin, sub, _, sup, _)), None) => {
  71                 Some((origin.span(), *sub, *sup))
  72             }
  73             (None, Some((span, sub, sup))) => Some((span, sub, sup)),
  74             _ => None,
  75         }
  76     }
  77 }