From 6e5cca79fcaaa80fbaaa23ba9f9c806f2ae8f41e Mon Sep 17 00:00:00 2001
From: Aman Arora <me@aman-arora.com>
Date: Wed, 25 Nov 2020 23:56:55 -0500
Subject: [PATCH] Use min_captures for creating UpvarSusbts::tupled_upvar_tys

- final_upvar_tys now reads types from places instead of using `node_ty`

Co-authored-by: Roxane Fruytier <roxane.fruytier@hotmail.com>
---
 compiler/rustc_middle/src/ty/context.rs  | 13 +++++++++
 compiler/rustc_typeck/src/check/upvar.rs | 37 +++++++++++-------------
 2 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 1b3416e112b..a8d007c0be2 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -624,6 +624,19 @@ impl<'tcx> TypeckResults<'tcx> {
         LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.pat_adjustments }
     }
 
+    /// For a given closure, returns the iterator of `ty::CapturedPlace`s that are captured
+    /// by the closure.
+    pub fn closure_min_captures_flattened(
+        &self,
+        closure_def_id: DefId,
+    ) -> impl Iterator<Item = &ty::CapturedPlace<'tcx>> {
+        self.closure_min_captures
+            .get(&closure_def_id)
+            .map(|closure_min_captures| closure_min_captures.values().flat_map(|v| v.iter()))
+            .into_iter()
+            .flatten()
+    }
+
     pub fn upvar_capture(&self, upvar_id: ty::UpvarId) -> ty::UpvarCapture<'tcx> {
         self.upvar_capture_map[&upvar_id]
     }
diff --git a/compiler/rustc_typeck/src/check/upvar.rs b/compiler/rustc_typeck/src/check/upvar.rs
index 019fa78fb1e..30b4682296c 100644
--- a/compiler/rustc_typeck/src/check/upvar.rs
+++ b/compiler/rustc_typeck/src/check/upvar.rs
@@ -202,7 +202,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // inference algorithm will reject it).
 
         // Equate the type variables for the upvars with the actual types.
-        let final_upvar_tys = self.final_upvar_tys(closure_hir_id);
+        let final_upvar_tys = self.final_upvar_tys(closure_def_id);
         debug!(
             "analyze_closure: id={:?} substs={:?} final_upvar_tys={:?}",
             closure_hir_id, substs, final_upvar_tys
@@ -222,36 +222,33 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 
     // Returns a list of `Ty`s for each upvar.
-    fn final_upvar_tys(&self, closure_id: hir::HirId) -> Vec<Ty<'tcx>> {
+    fn final_upvar_tys(&self, closure_id: DefId) -> Vec<Ty<'tcx>> {
         // Presently an unboxed closure type cannot "escape" out of a
         // function, so we will only encounter ones that originated in the
         // local crate or were inlined into it along with some function.
         // This may change if abstract return types of some sort are
         // implemented.
         let tcx = self.tcx;
-        let closure_def_id = tcx.hir().local_def_id(closure_id);
 
         self.typeck_results
             .borrow()
-            .closure_captures
-            .get(&closure_def_id.to_def_id())
-            .iter()
-            .flat_map(|upvars| {
-                upvars.iter().map(|(&var_hir_id, _)| {
-                    let upvar_ty = self.node_ty(var_hir_id);
-                    let upvar_id = ty::UpvarId::new(var_hir_id, closure_def_id);
-                    let capture = self.typeck_results.borrow().upvar_capture(upvar_id);
+            .closure_min_captures_flattened(closure_id)
+            .map(|captured_place| {
+                let upvar_ty = captured_place.place.ty();
+                let capture = captured_place.info.capture_kind;
 
-                    debug!("var_id={:?} upvar_ty={:?} capture={:?}", var_hir_id, upvar_ty, capture);
+                debug!(
+                    "place={:?} upvar_ty={:?} capture={:?}",
+                    captured_place.place, upvar_ty, capture
+                );
 
-                    match capture {
-                        ty::UpvarCapture::ByValue(_) => upvar_ty,
-                        ty::UpvarCapture::ByRef(borrow) => tcx.mk_ref(
-                            borrow.region,
-                            ty::TypeAndMut { ty: upvar_ty, mutbl: borrow.kind.to_mutbl_lossy() },
-                        ),
-                    }
-                })
+                match capture {
+                    ty::UpvarCapture::ByValue(_) => upvar_ty,
+                    ty::UpvarCapture::ByRef(borrow) => tcx.mk_ref(
+                        borrow.region,
+                        ty::TypeAndMut { ty: upvar_ty, mutbl: borrow.kind.to_mutbl_lossy() },
+                    ),
+                }
             })
             .collect()
     }