1 files changed, 77 insertions, 0 deletions
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs
new file mode 100644
index 000000000..53d9acf7d
--- /dev/null
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs
@@ -0,0 +1,77 @@
+use crate::infer::lexical_region_resolve::RegionResolutionError;
+use crate::infer::lexical_region_resolve::RegionResolutionError::*;
+use crate::infer::InferCtxt;
+use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
+use rustc_middle::ty::{self, TyCtxt};
+use rustc_span::source_map::Span;
+
+mod different_lifetimes;
+pub mod find_anon_type;
+mod mismatched_static_lifetime;
+mod named_anon_conflict;
+mod placeholder_error;
+mod static_impl_trait;
+mod trait_impl_difference;
+mod util;
+
+pub use different_lifetimes::suggest_adding_lifetime_params;
+pub use find_anon_type::find_anon_type;
+pub use static_impl_trait::{suggest_new_region_bound, HirTraitObjectVisitor, TraitObjectVisitor};
+pub use util::find_param_with_region;
+
+impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
+    pub fn try_report_nice_region_error(&self, error: &RegionResolutionError<'tcx>) -> bool {
+        NiceRegionError::new(self, error.clone()).try_report().is_some()
+    }
+}
+
+pub struct NiceRegionError<'cx, 'tcx> {
+    infcx: &'cx InferCtxt<'cx, 'tcx>,
+    error: Option<RegionResolutionError<'tcx>>,
+    regions: Option<(Span, ty::Region<'tcx>, ty::Region<'tcx>)>,
+}
+
+impl<'cx, 'tcx> NiceRegionError<'cx, 'tcx> {
+    pub fn new(infcx: &'cx InferCtxt<'cx, 'tcx>, error: RegionResolutionError<'tcx>) -> Self {
+        Self { infcx, error: Some(error), regions: None }
+    }
+
+    pub fn new_from_span(
+        infcx: &'cx InferCtxt<'cx, 'tcx>,
+        span: Span,
+        sub: ty::Region<'tcx>,
+        sup: ty::Region<'tcx>,
+    ) -> Self {
+        Self { infcx, error: None, regions: Some((span, sub, sup)) }
+    }
+
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.infcx.tcx
+    }
+
+    pub fn try_report_from_nll(&self) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+        // Due to the improved diagnostics returned by the MIR borrow checker, only a subset of
+        // the nice region errors are required when running under the MIR borrow checker.
+        self.try_report_named_anon_conflict().or_else(|| self.try_report_placeholder_conflict())
+    }
+
+    pub fn try_report(&self) -> Option<ErrorGuaranteed> {
+        self.try_report_from_nll()
+            .map(|mut diag| diag.emit())
+            .or_else(|| self.try_report_impl_not_conforming_to_trait())
+            .or_else(|| self.try_report_anon_anon_conflict())
+            .or_else(|| self.try_report_static_impl_trait())
+            .or_else(|| self.try_report_mismatched_static_lifetime())
+    }
+
+    pub(super) fn regions(&self) -> Option<(Span, ty::Region<'tcx>, ty::Region<'tcx>)> {
+        match (&self.error, self.regions) {
+            (Some(ConcreteFailure(origin, sub, sup)), None) => Some((origin.span(), *sub, *sup)),
+            (Some(SubSupConflict(_, _, origin, sub, _, sup, _)), None) => {
+                Some((origin.span(), *sub, *sup))
+            }
+            (None, Some((span, sub, sup))) => Some((span, sub, sup)),
+            _ => None,
+        }
+    }
+}