Don't use TypeckTables in NiceRegionError

Regions in TypeckTables will be erased, so are unusable for error
reporting.

Author: matthewjasper

src/librustc_infer/infer/error_reporting/nice_region_error/different_lifetimes.rs

@@ -3,6 +3,8 @@
 
 use crate::infer::error_reporting::nice_region_error::util::AnonymousParamInfo;
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
+use crate::infer::lexical_region_resolve::RegionResolutionError;
+use crate::infer::SubregionOrigin;
 use rustc::util::common::ErrorReported;
 
 use rustc_errors::struct_span_err;
@@ -47,6 +49,15 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     pub(super) fn try_report_anon_anon_conflict(&self) -> Option<ErrorReported> {
         let (span, sub, sup) = self.regions()?;
 
+        if let Some(RegionResolutionError::ConcreteFailure(
+            SubregionOrigin::ReferenceOutlivesReferent(..),
+            ..,
+        )) = self.error
+        {
+            // This error doesn't make much sense in this case.
+            return None;
+        }
+
         // Determine whether the sub and sup consist of both anonymous (elided) regions.
         let anon_reg_sup = self.tcx().is_suitable_region(sup)?;
 

src/librustc_infer/infer/error_reporting/nice_region_error/mod.rs

@@ -17,39 +17,28 @@ mod util;
 
 impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     pub fn try_report_nice_region_error(&self, error: &RegionResolutionError<'tcx>) -> bool {
-        if let Some(tables) = self.in_progress_tables {
-            let tables = tables.borrow();
-            NiceRegionError::new(self, error.clone(), Some(&tables)).try_report().is_some()
-        } else {
-            NiceRegionError::new(self, error.clone(), None).try_report().is_some()
-        }
+        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>)>,
-    tables: Option<&'cx ty::TypeckTables<'tcx>>,
 }
 
 impl<'cx, 'tcx> NiceRegionError<'cx, 'tcx> {
-    pub fn new(
-        infcx: &'cx InferCtxt<'cx, 'tcx>,
-        error: RegionResolutionError<'tcx>,
-        tables: Option<&'cx ty::TypeckTables<'tcx>>,
-    ) -> Self {
-        Self { infcx, error: Some(error), regions: None, tables }
+    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>,
-        tables: Option<&'cx ty::TypeckTables<'tcx>>,
     ) -> Self {
-        Self { infcx, error: None, regions: Some((span, sub, sup)), tables }
+        Self { infcx, error: None, regions: Some((span, sub, sup)) }
     }
 
     fn tcx(&self) -> TyCtxt<'tcx> {

src/librustc_infer/infer/error_reporting/nice_region_error/util.rs

@@ -51,52 +51,44 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         };
 
         let hir = &self.tcx().hir();
-        if let Some(hir_id) = hir.as_local_hir_id(id) {
-            if let Some(body_id) = hir.maybe_body_owned_by(hir_id) {
-                let body = hir.body(body_id);
-                let owner_id = hir.body_owner(body_id);
-                let fn_decl = hir.fn_decl_by_hir_id(owner_id).unwrap();
-                if let Some(tables) = self.tables {
-                    body.params
-                        .iter()
-                        .enumerate()
-                        .filter_map(|(index, param)| {
-                            // May return None; sometimes the tables are not yet populated.
-                            let ty_hir_id = fn_decl.inputs[index].hir_id;
-                            let param_ty_span = hir.span(ty_hir_id);
-                            let ty = tables.node_type_opt(param.hir_id)?;
-                            let mut found_anon_region = false;
-                            let new_param_ty = self.tcx().fold_regions(&ty, &mut false, |r, _| {
-                                if *r == *anon_region {
-                                    found_anon_region = true;
-                                    replace_region
-                                } else {
-                                    r
-                                }
-                            });
-                            if found_anon_region {
-                                let is_first = index == 0;
-                                Some(AnonymousParamInfo {
-                                    param,
-                                    param_ty: new_param_ty,
-                                    param_ty_span,
-                                    bound_region,
-                                    is_first,
-                                })
-                            } else {
-                                None
-                            }
-                        })
-                        .next()
+        let hir_id = hir.as_local_hir_id(id)?;
+        let body_id = hir.maybe_body_owned_by(hir_id)?;
+        let body = hir.body(body_id);
+        let owner_id = hir.body_owner(body_id);
+        let fn_decl = hir.fn_decl_by_hir_id(owner_id).unwrap();
+        let poly_fn_sig = self.tcx().fn_sig(id);
+        let fn_sig = self.tcx().liberate_late_bound_regions(id, &poly_fn_sig);
+        body.params
+            .iter()
+            .enumerate()
+            .filter_map(|(index, param)| {
+                // May return None; sometimes the tables are not yet populated.
+                let ty = fn_sig.inputs()[index];
+                let mut found_anon_region = false;
+                let new_param_ty = self.tcx().fold_regions(&ty, &mut false, |r, _| {
+                    if *r == *anon_region {
+                        found_anon_region = true;
+                        replace_region
+                    } else {
+                        r
+                    }
+                });
+                if found_anon_region {
+                    let ty_hir_id = fn_decl.inputs[index].hir_id;
+                    let param_ty_span = hir.span(ty_hir_id);
+                    let is_first = index == 0;
+                    Some(AnonymousParamInfo {
+                        param,
+                        param_ty: new_param_ty,
+                        param_ty_span,
+                        bound_region,
+                        is_first,
+                    })
                 } else {
                     None
                 }
-            } else {
-                None
-            }
-        } else {
-            None
-        }
+            })
+            .next()
     }
 
     // Here, we check for the case where the anonymous region

src/librustc_mir/borrow_check/diagnostics/region_errors.rs

@@ -284,8 +284,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         debug!("report_region_error: category={:?} {:?}", category, span);
         // Check if we can use one of the "nice region errors".
         if let (Some(f), Some(o)) = (self.to_error_region(fr), self.to_error_region(outlived_fr)) {
-            let tables = self.infcx.tcx.typeck_tables_of(self.mir_def_id);
-            let nice = NiceRegionError::new_from_span(self.infcx, span, o, f, Some(tables));
+            let nice = NiceRegionError::new_from_span(self.infcx, span, o, f);
             if let Some(diag) = nice.try_report_from_nll() {
                 diag.buffer(&mut self.errors_buffer);
                 return;