]> git.lizzy.rs Git - rust.git/blobdiff - src/librustc_mir/borrow_check/diagnostics/region_name.rs
Rollup merge of #75485 - RalfJung:pin, r=nagisa
[rust.git] / src / librustc_mir / borrow_check / diagnostics / region_name.rs
index 233f8158e2b76ef998cb1bc25ea06a80d1c154f6..2603b1e048d81ebe793a394dddad81d4e9db7f37 100644 (file)
@@ -266,7 +266,7 @@ fn give_name_from_error_region(&self, fr: RegionVid) -> Option<RegionName> {
                 }
 
                 ty::BoundRegion::BrEnv => {
-                    let mir_hir_id = self.infcx.tcx.hir().as_local_hir_id(self.mir_def_id);
+                    let mir_hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(self.mir_def_id);
                     let def_ty = self.regioncx.universal_regions().defining_ty;
 
                     if let DefiningTy::Closure(_, substs) = def_ty {
@@ -336,22 +336,32 @@ fn give_name_if_anonymous_region_appears_in_arguments(
 
         let arg_ty = self.regioncx.universal_regions().unnormalized_input_tys
             [implicit_inputs + argument_index];
-        if let Some(region_name) =
-            self.give_name_if_we_can_match_hir_ty_from_argument(fr, arg_ty, argument_index)
-        {
-            return Some(region_name);
-        }
+        let (_, span) = self.regioncx.get_argument_name_and_span_for_region(
+            &self.body,
+            &self.local_names,
+            argument_index,
+        );
 
-        self.give_name_if_we_cannot_match_hir_ty(fr, arg_ty)
+        self.get_argument_hir_ty_for_highlighting(argument_index)
+            .and_then(|arg_hir_ty| self.highlight_if_we_can_match_hir_ty(fr, arg_ty, arg_hir_ty))
+            .or_else(|| {
+                // `highlight_if_we_cannot_match_hir_ty` needs to know the number we will give to
+                // the anonymous region. If it succeeds, the `synthesize_region_name` call below
+                // will increment the counter, "reserving" the number we just used.
+                let counter = *self.next_region_name.try_borrow().unwrap();
+                self.highlight_if_we_cannot_match_hir_ty(fr, arg_ty, span, counter)
+            })
+            .map(|highlight| RegionName {
+                name: self.synthesize_region_name(),
+                source: RegionNameSource::AnonRegionFromArgument(highlight),
+            })
     }
 
-    fn give_name_if_we_can_match_hir_ty_from_argument(
+    fn get_argument_hir_ty_for_highlighting(
         &self,
-        needle_fr: RegionVid,
-        argument_ty: Ty<'tcx>,
         argument_index: usize,
-    ) -> Option<RegionName> {
-        let mir_hir_id = self.infcx.tcx.hir().as_local_hir_id(self.mir_def_id);
+    ) -> Option<&hir::Ty<'tcx>> {
+        let mir_hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(self.mir_def_id);
         let fn_decl = self.infcx.tcx.hir().fn_decl_by_hir_id(mir_hir_id)?;
         let argument_hir_ty: &hir::Ty<'_> = fn_decl.inputs.get(argument_index)?;
         match argument_hir_ty.kind {
@@ -362,7 +372,7 @@ fn give_name_if_we_can_match_hir_ty_from_argument(
             // (`give_name_if_anonymous_region_appears_in_arguments`).
             hir::TyKind::Infer => None,
 
-            _ => self.give_name_if_we_can_match_hir_ty(needle_fr, argument_ty, argument_hir_ty),
+            _ => Some(argument_hir_ty),
         }
     }
 
@@ -377,44 +387,28 @@ fn give_name_if_we_can_match_hir_ty_from_argument(
     ///  |          |  has type `&'1 u32`
     ///  |          has type `&'2 u32`
     /// ```
-    fn give_name_if_we_cannot_match_hir_ty(
+    fn highlight_if_we_cannot_match_hir_ty(
         &self,
         needle_fr: RegionVid,
-        argument_ty: Ty<'tcx>,
-    ) -> Option<RegionName> {
-        let counter = *self.next_region_name.try_borrow().unwrap();
+        ty: Ty<'tcx>,
+        span: Span,
+        counter: usize,
+    ) -> Option<RegionNameHighlight> {
         let mut highlight = RegionHighlightMode::default();
         highlight.highlighting_region_vid(needle_fr, counter);
-        let type_name = self.infcx.extract_type_name(&argument_ty, Some(highlight)).0;
+        let type_name = self.infcx.extract_type_name(&ty, Some(highlight)).0;
 
         debug!(
-            "give_name_if_we_cannot_match_hir_ty: type_name={:?} needle_fr={:?}",
+            "highlight_if_we_cannot_match_hir_ty: type_name={:?} needle_fr={:?}",
             type_name, needle_fr
         );
-        let assigned_region_name = if type_name.find(&format!("'{}", counter)).is_some() {
+        if type_name.find(&format!("'{}", counter)).is_some() {
             // Only add a label if we can confirm that a region was labelled.
-            let argument_index =
-                self.regioncx.get_argument_index_for_region(self.infcx.tcx, needle_fr)?;
-            let (_, span) = self.regioncx.get_argument_name_and_span_for_region(
-                &self.body,
-                &self.local_names,
-                argument_index,
-            );
-
-            Some(RegionName {
-                // This counter value will already have been used, so this function will increment
-                // it so the next value will be used next and return the region name that would
-                // have been used.
-                name: self.synthesize_region_name(),
-                source: RegionNameSource::AnonRegionFromArgument(
-                    RegionNameHighlight::CannotMatchHirTy(span, type_name),
-                ),
-            })
+
+            Some(RegionNameHighlight::CannotMatchHirTy(span, type_name))
         } else {
             None
-        };
-
-        assigned_region_name
+        }
     }
 
     /// Attempts to highlight the specific part of a type annotation
@@ -426,9 +420,9 @@ fn give_name_if_we_cannot_match_hir_ty(
     ///  |                - let's call the lifetime of this reference `'1`
     /// ```
     ///
-    /// the way this works is that we match up `argument_ty`, which is
+    /// the way this works is that we match up `ty`, which is
     /// a `Ty<'tcx>` (the internal form of the type) with
-    /// `argument_hir_ty`, a `hir::Ty` (the syntax of the type
+    /// `hir_ty`, a `hir::Ty` (the syntax of the type
     /// annotation). We are descending through the types stepwise,
     /// looking in to find the region `needle_fr` in the internal
     /// type. Once we find that, we can use the span of the `hir::Ty`
@@ -438,18 +432,17 @@ fn give_name_if_we_cannot_match_hir_ty(
     /// keep track of the **closest** type we've found. If we fail to
     /// find the exact `&` or `'_` to highlight, then we may fall back
     /// to highlighting that closest type instead.
-    fn give_name_if_we_can_match_hir_ty(
+    fn highlight_if_we_can_match_hir_ty(
         &self,
         needle_fr: RegionVid,
-        argument_ty: Ty<'tcx>,
-        argument_hir_ty: &hir::Ty<'_>,
-    ) -> Option<RegionName> {
-        let search_stack: &mut Vec<(Ty<'tcx>, &hir::Ty<'_>)> =
-            &mut vec![(argument_ty, argument_hir_ty)];
+        ty: Ty<'tcx>,
+        hir_ty: &hir::Ty<'_>,
+    ) -> Option<RegionNameHighlight> {
+        let search_stack: &mut Vec<(Ty<'tcx>, &hir::Ty<'_>)> = &mut vec![(ty, hir_ty)];
 
         while let Some((ty, hir_ty)) = search_stack.pop() {
             match (&ty.kind, &hir_ty.kind) {
-                // Check if the `argument_ty` is `&'X ..` where `'X`
+                // Check if the `ty` is `&'X ..` where `'X`
                 // is the region we are looking for -- if so, and we have a `&T`
                 // on the RHS, then we want to highlight the `&` like so:
                 //
@@ -460,18 +453,11 @@ fn give_name_if_we_can_match_hir_ty(
                     hir::TyKind::Rptr(_lifetime, referent_hir_ty),
                 ) => {
                     if region.to_region_vid() == needle_fr {
-                        let region_name = self.synthesize_region_name();
-
                         // Just grab the first character, the `&`.
                         let source_map = self.infcx.tcx.sess.source_map();
                         let ampersand_span = source_map.start_point(hir_ty.span);
 
-                        return Some(RegionName {
-                            name: region_name,
-                            source: RegionNameSource::AnonRegionFromArgument(
-                                RegionNameHighlight::MatchedHirTy(ampersand_span),
-                            ),
-                        });
+                        return Some(RegionNameHighlight::MatchedHirTy(ampersand_span));
                     }
 
                     // Otherwise, let's descend into the referent types.
@@ -491,13 +477,13 @@ fn give_name_if_we_can_match_hir_ty(
                         Res::Def(DefKind::TyAlias, _) => (),
                         _ => {
                             if let Some(last_segment) = path.segments.last() {
-                                if let Some(name) = self.match_adt_and_segment(
+                                if let Some(highlight) = self.match_adt_and_segment(
                                     substs,
                                     needle_fr,
                                     last_segment,
                                     search_stack,
                                 ) {
-                                    return Some(name);
+                                    return Some(highlight);
                                 }
                             }
                         }
@@ -540,7 +526,7 @@ fn match_adt_and_segment<'hir>(
         needle_fr: RegionVid,
         last_segment: &'hir hir::PathSegment<'hir>,
         search_stack: &mut Vec<(Ty<'tcx>, &'hir hir::Ty<'hir>)>,
-    ) -> Option<RegionName> {
+    ) -> Option<RegionNameHighlight> {
         // Did the user give explicit arguments? (e.g., `Foo<..>`)
         let args = last_segment.args.as_ref()?;
         let lifetime =
@@ -550,14 +536,8 @@ fn match_adt_and_segment<'hir>(
             | hir::LifetimeName::Error
             | hir::LifetimeName::Static
             | hir::LifetimeName::Underscore => {
-                let region_name = self.synthesize_region_name();
                 let lifetime_span = lifetime.span;
-                Some(RegionName {
-                    name: region_name,
-                    source: RegionNameSource::AnonRegionFromArgument(
-                        RegionNameHighlight::MatchedAdtAndSegment(lifetime_span),
-                    ),
-                })
+                Some(RegionNameHighlight::MatchedAdtAndSegment(lifetime_span))
             }
 
             hir::LifetimeName::ImplicitObjectLifetimeDefault | hir::LifetimeName::Implicit => {
@@ -668,7 +648,7 @@ fn give_name_if_anonymous_region_appears_in_output(&self, fr: RegionVid) -> Opti
         highlight.highlighting_region_vid(fr, *self.next_region_name.try_borrow().unwrap());
         let type_name = self.infcx.extract_type_name(&return_ty, Some(highlight)).0;
 
-        let mir_hir_id = tcx.hir().as_local_hir_id(self.mir_def_id);
+        let mir_hir_id = tcx.hir().local_def_id_to_hir_id(self.mir_def_id);
 
         let (return_span, mir_description) = match tcx.hir().get(mir_hir_id) {
             hir::Node::Expr(hir::Expr {
@@ -720,7 +700,7 @@ fn give_name_if_anonymous_region_appears_in_yield_ty(
         highlight.highlighting_region_vid(fr, *self.next_region_name.try_borrow().unwrap());
         let type_name = self.infcx.extract_type_name(&yield_ty, Some(highlight)).0;
 
-        let mir_hir_id = tcx.hir().as_local_hir_id(self.mir_def_id);
+        let mir_hir_id = tcx.hir().local_def_id_to_hir_id(self.mir_def_id);
 
         let yield_span = match tcx.hir().get(mir_hir_id) {
             hir::Node::Expr(hir::Expr {