2229: Drop any deref in move closure

compiler/rustc_typeck/src/check/upvar.rs

@@ -1896,31 +1896,20 @@ fn restrict_capture_precision<'tcx>(
  return (place, curr_mode);
 }
 
-/// Take ownership if data being accessed is owned by the variable used to access it
-/// (or if closure attempts to move data that it doesn’t own).
-/// Note: When taking ownership, only capture data found on the stack.
+/// Truncate deref of any reference.
 fn adjust_for_move_closure<'tcx>(
  mut place: Place<'tcx>,
  mut kind: ty::UpvarCapture<'tcx>,
 ) -> (Place<'tcx>, ty::UpvarCapture<'tcx>) {
- let contains_deref_of_ref = place.deref_tys().any(|ty| ty.is_ref());
  let first_deref = place.projections.iter().position(|proj| proj.kind == ProjectionKind::Deref);
 
- match kind {
- ty::UpvarCapture::ByRef(..) if contains_deref_of_ref => (place, kind),
-
- // If there's any Deref and the data needs to be moved into the closure body,
- // or it's a Deref of a Box, truncate the path to the first deref
- _ => {
- if let Some(idx) = first_deref {
- truncate_place_to_len_and_update_capture_kind(&mut place, &mut kind, idx);
- }
-
- // AMAN: I think we don't need the span inside the ByValue anymore
- // we have more detailed span in CaptureInfo
- (place, ty::UpvarCapture::ByValue(None))
- }
+ if let Some(idx) = first_deref {
+ truncate_place_to_len_and_update_capture_kind(&mut place, &mut kind, idx);
  }
+
+ // AMAN: I think we don't need the span inside the ByValue anymore
+ // we have more detailed span in CaptureInfo
+ (place, ty::UpvarCapture::ByValue(None))
 }
 
 /// Adjust closure capture just that if taking ownership of data, only move data

src/test/ui/closures/2229_closure_analysis/move_closure.rs

@@ -35,7 +35,7 @@ fn simple_ref() {
  //~| ERROR: Min Capture analysis includes:
  *ref_s += 10;
  //~^ NOTE: Capturing ref_s[Deref] -> MutBorrow
- //~| NOTE: Min Capture ref_s[Deref] -> MutBorrow
+ //~| NOTE: Min Capture ref_s[] -> ByValue
  };
  c();
 }
@@ -56,7 +56,7 @@ fn struct_contains_ref_to_another_struct_1() {
  //~| ERROR: Min Capture analysis includes:
  t.0.0 = "new s".into();
  //~^ NOTE: Capturing t[(0, 0),Deref,(0, 0)] -> MutBorrow
- //~| NOTE: Min Capture t[(0, 0),Deref,(0, 0)] -> MutBorrow
+ //~| NOTE: Min Capture t[(0, 0)] -> ByValue
  };
 
  c();
@@ -79,7 +79,7 @@ fn struct_contains_ref_to_another_struct_2() {
  //~| ERROR: Min Capture analysis includes:
  let _t = t.0.0;
  //~^ NOTE: Capturing t[(0, 0),Deref,(0, 0)] -> ImmBorrow
- //~| NOTE: Min Capture t[(0, 0),Deref] -> ImmBorrow
+ //~| NOTE: Min Capture t[(0, 0)] -> ByValue
  };
 
  c();
@@ -175,7 +175,7 @@ fn box_mut_1() {
  //~| First Pass analysis includes:
  //~| NOTE: Capturing box_p_foo[Deref,Deref,(0, 0)] -> MutBorrow
  //~| Min Capture analysis includes:
- //~| NOTE: Min Capture box_p_foo[Deref,Deref,(0, 0)] -> MutBorrow
+ //~| NOTE: Min Capture box_p_foo[] -> ByValue
 }
 
 // Ensure that even in move closures, if the data is not owned by the root variable
@@ -192,7 +192,7 @@ fn box_mut_2() {
  //~| First Pass analysis includes:
  //~| NOTE: Capturing p_foo[Deref,Deref,(0, 0)] -> MutBorrow
  //~| Min Capture analysis includes:
- //~| NOTE: Min Capture p_foo[Deref,Deref,(0, 0)] -> MutBorrow
+ //~| NOTE: Min Capture p_foo[] -> ByValue
 }
 
 // Test that move closures can take ownership of Copy type

src/test/ui/closures/2229_closure_analysis/move_closure.stderr

@@ -187,7 +187,7 @@ LL | |
 LL | | };
  | |_____^
  |
-note: Min Capture ref_s[Deref] -> MutBorrow
+note: Min Capture ref_s[] -> ByValue
  --> $DIR/move_closure.rs:36:9
  |
 LL | *ref_s += 10;
@@ -223,7 +223,7 @@ LL | |
 LL | | };
  | |_____^
  |
-note: Min Capture t[(0, 0),Deref,(0, 0)] -> MutBorrow
+note: Min Capture t[(0, 0)] -> ByValue
  --> $DIR/move_closure.rs:57:9
  |
 LL | t.0.0 = "new s".into();
@@ -259,7 +259,7 @@ LL | |
 LL | | };
  | |_____^
  |
-note: Min Capture t[(0, 0),Deref] -> ImmBorrow
+note: Min Capture t[(0, 0)] -> ByValue
  --> $DIR/move_closure.rs:80:18
  |
 LL | let _t = t.0.0;
@@ -427,7 +427,7 @@ error: Min Capture analysis includes:
 LL | let c = #[rustc_capture_analysis] move || box_p_foo.x += 10;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^
  |
-note: Min Capture box_p_foo[Deref,Deref,(0, 0)] -> MutBorrow
+note: Min Capture box_p_foo[] -> ByValue
  --> $DIR/move_closure.rs:172:47
  |
 LL | let c = #[rustc_capture_analysis] move || box_p_foo.x += 10;
@@ -451,7 +451,7 @@ error: Min Capture analysis includes:
 LL | let c = #[rustc_capture_analysis] move || p_foo.x += 10;
  | ^^^^^^^^^^^^^^^^^^^^^
  |
-note: Min Capture p_foo[Deref,Deref,(0, 0)] -> MutBorrow
+note: Min Capture p_foo[] -> ByValue
  --> $DIR/move_closure.rs:189:47
  |
 LL | let c = #[rustc_capture_analysis] move || p_foo.x += 10;

src/test/ui/closures/2229_closure_analysis/run_pass/issue-88431.rs

@@ -0,0 +1,59 @@
+// edition:2021
+// check-pass
+
+use std::collections::HashMap;
+use std::future::Future;
+use std::pin::Pin;
+
+pub struct GameMode {}
+
+struct GameStateManager<'a> {
+ gamestate_stack: Vec<Box<dyn GameState<'a> + 'a>>,
+}
+
+pub trait GameState<'a> {}
+
+async fn construct_gamestate_replay<'a>(
+ _gamemode: &GameMode,
+ _factory: &mut GameStateManager<'a>,
+) -> Box<dyn GameState<'a> + 'a> {
+ unimplemented!()
+}
+
+type FutureGameState<'a, 'b> = Pin<Box<dyn Future<Output = Box<dyn GameState<'a> + 'a>> + 'b>>;
+
+struct MenuOption<'a> {
+ command: Box<dyn for<'b> Fn(&'b mut GameStateManager<'a>) -> FutureGameState<'a, 'b> + 'a>,
+}
+
+impl<'a> MenuOption<'a> {
+ fn new(
+ _command: impl for<'b> Fn(&'b mut GameStateManager<'a>) -> FutureGameState<'a, 'b> + 'a,
+ ) -> Self {
+ unimplemented!()
+ }
+}
+
+struct MenuState<'a> {
+ options: Vec<MenuOption<'a>>,
+}
+
+impl<'a> GameState<'a> for MenuState<'a> {}
+
+pub async fn get_replay_menu<'a>(
+ gamemodes: &'a HashMap<&str, GameMode>,
+) -> Box<dyn GameState<'a> + 'a> {
+ let recordings: Vec<String> = vec![];
+ let _ = recordings
+ .into_iter()
+ .map(|entry| {
+ MenuOption::new(move |f| {
+ Box::pin(construct_gamestate_replay(&gamemodes[entry.as_str()], f))
+ })
+ })
+ .collect::<Vec<_>>();
+
+ todo!()
+}
+
+fn main() {}

src/test/ui/closures/2229_closure_analysis/run_pass/move_closure.rs

@@ -56,28 +56,6 @@ fn no_ref_nested() {
  c();
 }
 
-struct A<'a>(&'a mut String, &'a mut String);
-// Test that reborrowing works as expected for move closures
-// by attempting a disjoint capture through a reference.
-fn disjoint_via_ref() {
- let mut x = String::new();
- let mut y = String::new();
-
- let mut a = A(&mut x, &mut y);
- let a = &mut a;
-
- let mut c1 = move || {
- a.0.truncate(0);
- };
-
- let mut c2 = move || {
- a.1.truncate(0);
- };
-
- c1();
- c2();
-}
-
 // Test that even if a path is moved into the closure, the closure is not FnOnce
 // if the path is not moved by the closure call.
 fn data_moved_but_not_fn_once() {
@@ -109,7 +87,6 @@ fn main() {
  no_ref();
  no_ref_nested();
 
- disjoint_via_ref();
  data_moved_but_not_fn_once();
 
  returned_closure_owns_copy_type_data();

src/test/ui/nll/closure-use-spans.stderr

@@ -26,7 +26,7 @@ LL | let y = &x;
 LL | x = 0;
  | ^^^^^ assignment to borrowed `x` occurs here
 LL | move || *y;
- |  - borrow later captured here by closure
+ | -- borrow later captured here by closure
 
 error: aborting due to 3 previous errors