[Don't merge] Perf test for using closure precise capture

.gitmodules

@@ -43,7 +43,8 @@
 	url = https://github.com/rust-embedded/book.git
 [submodule "src/tools/rust-analyzer"]
 	path = src/tools/rust-analyzer
-	url = https://github.com/rust-analyzer/rust-analyzer.git
+	url = https://github.com/arora-aman/rust-analyzer.git
+    branch = perf-2229
 [submodule "library/backtrace"]
 	path = library/backtrace
 	url = https://github.com/rust-lang/backtrace-rs.git

compiler/rustc_error_codes/src/error_codes/E0504.md

@@ -5,25 +5,6 @@ closure.
 
 Erroneous code example:
 
-```compile_fail
-struct FancyNum {
-    num: u8,
-}
-
-fn main() {
-    let fancy_num = FancyNum { num: 5 };
-    let fancy_ref = &fancy_num;
-
-    let x = move || {
-        println!("child function: {}", fancy_num.num);
-        // error: cannot move `fancy_num` into closure because it is borrowed
-    };
-
-    x();
-    println!("main function: {}", fancy_ref.num);
-}
-```
-
 Here, `fancy_num` is borrowed by `fancy_ref` and so cannot be moved into
 the closure `x`. There is no way to move a value into a closure while it is
 borrowed, as that would invalidate the borrow.

compiler/rustc_interface/src/util.rs

@@ -120,8 +120,14 @@ pub fn scoped_thread<F: FnOnce() -> R + Send, R: Send>(cfg: thread::Builder, f:
     let result_ptr = Ptr(&mut result as *mut _ as *mut ());
 
     let thread = cfg.spawn(move || {
-        let run = unsafe { (*(run.0 as *mut Option<F>)).take().unwrap() };
-        let result = unsafe { &mut *(result_ptr.0 as *mut Option<R>) };
+        let run = unsafe {
+            let x = run;
+            (*(x.0 as *mut Option<F>)).take().unwrap()
+        };
+        let result = unsafe {
+            let x = result_ptr;
+            &mut *(x.0 as *mut Option<R>)
+        };
         *result = Some(run());
     });
 

compiler/rustc_middle/src/hir/place.rs

@@ -4,7 +4,18 @@ use crate::ty::Ty;
 use rustc_hir::HirId;
 use rustc_target::abi::VariantIdx;
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    PartialEq,
+    Eq,
+    Hash,
+    TyEncodable,
+    TyDecodable,
+    TypeFoldable,
+    HashStable
+)]
 pub enum PlaceBase {
     /// A temporary variable
     Rvalue,
@@ -16,7 +27,18 @@ pub enum PlaceBase {
     Upvar(ty::UpvarId),
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    PartialEq,
+    Eq,
+    Hash,
+    TyEncodable,
+    TyDecodable,
+    TypeFoldable,
+    HashStable
+)]
 pub enum ProjectionKind {
     /// A dereference of a pointer, reference or `Box<T>` of the given type
     Deref,
@@ -36,7 +58,18 @@ pub enum ProjectionKind {
     Subslice,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    PartialEq,
+    Eq,
+    Hash,
+    TyEncodable,
+    TyDecodable,
+    TypeFoldable,
+    HashStable
+)]
 pub struct Projection<'tcx> {
     /// Type after the projection is being applied.
     pub ty: Ty<'tcx>,
@@ -48,7 +81,7 @@ pub struct Projection<'tcx> {
 /// A `Place` represents how a value is located in memory.
 ///
 /// This is an HIR version of `mir::Place`
-#[derive(Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub struct Place<'tcx> {
     /// The type of the `PlaceBase`
     pub base_ty: Ty<'tcx>,
@@ -61,7 +94,7 @@ pub struct Place<'tcx> {
 /// A `PlaceWithHirId` represents how a value is located in memory.
 ///
 /// This is an HIR version of `mir::Place`
-#[derive(Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub struct PlaceWithHirId<'tcx> {
     /// `HirId` of the expression or pattern producing this value.
     pub hir_id: HirId,

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]
     }

compiler/rustc_middle/src/ty/mod.rs

@@ -672,15 +672,26 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TyS<'tcx> {
 #[rustc_diagnostic_item = "Ty"]
 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    PartialEq,
+    Eq,
+    Hash,
+    TyEncodable,
+    TyDecodable,
+    TypeFoldable,
+    HashStable
+)]
 pub struct UpvarPath {
     pub hir_id: hir::HirId,
 }
 
 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
 /// the original var ID (that is, the root variable that is referenced
 /// by the upvar) and the ID of the closure expression.
-#[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub struct UpvarId {
     pub var_path: UpvarPath,
     pub closure_expr_id: LocalDefId,
@@ -692,7 +703,7 @@ impl UpvarId {
     }
 }
 
-#[derive(Clone, PartialEq, Debug, TyEncodable, TyDecodable, Copy, HashStable)]
+#[derive(Clone, PartialEq, Debug, TyEncodable, TyDecodable, TypeFoldable, Copy, HashStable)]
 pub enum BorrowKind {
     /// Data must be immutable and is aliasable.
     ImmBorrow,
@@ -746,7 +757,7 @@ pub enum BorrowKind {
 
 /// Information describing the capture of an upvar. This is computed
 /// during `typeck`, specifically by `regionck`.
-#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, HashStable)]
+#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub enum UpvarCapture<'tcx> {
     /// Upvar is captured by value. This is always true when the
     /// closure is labeled `move`, but can also be true in other cases
@@ -763,7 +774,7 @@ pub enum UpvarCapture<'tcx> {
     ByRef(UpvarBorrow<'tcx>),
 }
 
-#[derive(PartialEq, Clone, Copy, TyEncodable, TyDecodable, HashStable)]
+#[derive(PartialEq, Clone, Copy, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub struct UpvarBorrow<'tcx> {
     /// The kind of borrow: by-ref upvars have access to shared
     /// immutable borrows, which are not part of the normal language
@@ -790,16 +801,17 @@ pub type RootVariableMinCaptureList<'tcx> = FxIndexMap<hir::HirId, MinCaptureLis
 pub type MinCaptureList<'tcx> = Vec<CapturedPlace<'tcx>>;
 
 /// A `Place` and the corresponding `CaptureInfo`.
-#[derive(PartialEq, Clone, Debug, TyEncodable, TyDecodable, HashStable)]
+#[derive(PartialEq, Clone, Debug, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub struct CapturedPlace<'tcx> {
     pub place: HirPlace<'tcx>,
     pub info: CaptureInfo<'tcx>,
+    pub mutability: hir::Mutability,
 }
 
 /// Part of `MinCaptureInformationMap`; describes the capture kind (&, &mut, move)
 /// for a particular capture as well as identifying the part of the source code
 /// that triggered this capture to occur.
-#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, HashStable)]
+#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub struct CaptureInfo<'tcx> {
     /// Expr Id pointing to use that resulted in selecting the current capture kind
     ///

compiler/rustc_middle/src/ty/sty.rs

@@ -2174,6 +2174,15 @@ impl<'tcx> TyS<'tcx> {
         }
     }
 
+    /// Get the `i`-th element of a tuple.
+    /// Panics when called on anything but a tuple.
+    pub fn tuple_get_field(&self, i: usize) -> Option<Ty<'tcx>> {
+        match self.kind() {
+            Tuple(substs) => substs.iter().nth(i).map(|field| field.expect_ty()),
+            _ => bug!("tuple_fields called on non-tuple"),
+        }
+    }
+
     /// If the type contains variants, returns the valid range of variant indices.
     //
     // FIXME: This requires the optimized MIR in the case of generators.

compiler/rustc_mir/src/borrow_check/mod.rs

@@ -9,6 +9,7 @@ use rustc_hir::{HirId, Node};
 use rustc_index::bit_set::BitSet;
 use rustc_index::vec::IndexVec;
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
+use rustc_middle::hir::place::PlaceBase as HirPlaceBase;
 use rustc_middle::mir::{
     traversal, Body, ClearCrossCrate, Local, Location, Mutability, Operand, Place, PlaceElem,
     PlaceRef,
@@ -75,6 +76,7 @@ crate use region_infer::RegionInferenceContext;
 crate struct Upvar {
     name: Symbol,
 
+    // FIXME(project-rfc-2229#8): This should use Place or something similar
     var_hir_id: HirId,
 
     /// If true, the capture is behind a reference.
@@ -155,28 +157,23 @@ fn do_mir_borrowck<'a, 'tcx>(
         infcx.set_tainted_by_errors();
     }
     let upvars: Vec<_> = tables
-        .closure_captures
-        .get(&def.did.to_def_id())
-        .into_iter()
-        .flat_map(|v| v.values())
-        .map(|upvar_id| {
-            let var_hir_id = upvar_id.var_path.hir_id;
-            let capture = tables.upvar_capture(*upvar_id);
+        .closure_min_captures_flattened(def.did.to_def_id())
+        .map(|captured_place| {
+            let var_hir_id = match captured_place.place.base {
+                HirPlaceBase::Upvar(upvar_id) => upvar_id.var_path.hir_id,
+                _ => bug!("Expected upvar"),
+            };
+            let capture = captured_place.info.capture_kind;
             let by_ref = match capture {
                 ty::UpvarCapture::ByValue(_) => false,
                 ty::UpvarCapture::ByRef(..) => true,
             };
-            let mut upvar = Upvar {
+            Upvar {
                 name: tcx.hir().name(var_hir_id),
                 var_hir_id,
                 by_ref,
-                mutability: Mutability::Not,
-            };
-            let bm = *tables.pat_binding_modes().get(var_hir_id).expect("missing binding mode");
-            if bm == ty::BindByValue(hir::Mutability::Mut) {
-                upvar.mutability = Mutability::Mut;
+                mutability: captured_place.mutability,
             }
-            upvar
         })
         .collect();
 

compiler/rustc_mir/src/borrow_check/type_check/mod.rs

@@ -749,7 +749,11 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
                     (&adt_def.variants[VariantIdx::new(0)], substs)
                 }
                 ty::Closure(_, substs) => {
-                    return match substs.as_closure().upvar_tys().nth(field.index()) {
+                    return match substs
+                        .as_closure()
+                        .tupled_upvars_ty()
+                        .tuple_get_field(field.index())
+                    {
                         Some(ty) => Ok(ty),
                         None => Err(FieldAccessError::OutOfRange {
                             field_count: substs.as_closure().upvar_tys().count(),