Move subtyper below reveal_all and change reveal_all

compiler/rustc_mir_transform/src/add_subtyping_projections.rs

@@ -24,6 +24,11 @@ impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeChecker<'a, 'tcx> {
  rvalue: &mut Rvalue<'tcx>,
  location: Location,
  ) {
+ // We don't need to do anything for deref temps as they are
+ // not part of the source code, but used for desugaring purposes.
+ if self.local_decls[place.local].is_deref_temp() {
+ return;
+ }
  let mut place_ty = place.ty(self.local_decls, self.tcx).ty;
  let mut rval_ty = rvalue.ty(self.local_decls, self.tcx);
  // Not erasing this causes `Free Regions` errors in validator,
@@ -48,7 +53,6 @@ impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeChecker<'a, 'tcx> {
 // // gets transformed to
 // let temp: rval_ty = rval;
 // let place: place_ty = temp as place_ty;
-//
 pub fn subtype_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
  let patch = MirPatch::new(body);
  let mut checker = SubTypeChecker { tcx, patcher: patch, local_decls: &body.local_decls };

compiler/rustc_mir_transform/src/lib.rs

@@ -467,7 +467,6 @@ pub fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'
 /// After this series of passes, no lifetime analysis based on borrowing can be done.
 fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
  let passes: &[&dyn MirPass<'tcx>] = &[
- &add_subtyping_projections::Subtyper,
  &cleanup_post_borrowck::CleanupPostBorrowck,
  &remove_noop_landing_pads::RemoveNoopLandingPads,
  &simplify::SimplifyCfg::EarlyOpt,
@@ -483,6 +482,7 @@ fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
  // These next passes must be executed together
  &add_call_guards::CriticalCallEdges,
  &reveal_all::RevealAll, // has to be done before drop elaboration, since we need to drop opaque types, too.
+ &add_subtyping_projections::Subtyper, // calling this after reveal_all ensures that we don't deal with opaque types
  &elaborate_drops::ElaborateDrops,
  // This will remove extraneous landing pads which are no longer
  // necessary as well as well as forcing any call in a non-unwinding

compiler/rustc_mir_transform/src/reveal_all.rs

@@ -46,16 +46,18 @@ impl<'tcx> MutVisitor<'tcx> for RevealAllVisitor<'tcx> {
  .filter(|elem| !matches!(elem, ProjectionElem::OpaqueCast(_)))
  .collect::<Vec<_>>(),
  );
+ self.super_place(place, _context, _location);
  }
 
  #[inline]
- fn visit_constant(&mut self, constant: &mut ConstOperand<'tcx>, _: Location) {
+ fn visit_constant(&mut self, constant: &mut ConstOperand<'tcx>, location: Location) {
  // We have to use `try_normalize_erasing_regions` here, since it's
  // possible that we visit impossible-to-satisfy where clauses here,
  // see #91745
  if let Ok(c) = self.tcx.try_normalize_erasing_regions(self.param_env, constant.const_) {
  constant.const_ = c;
  }
+ self.super_constant(constant, location);
  }
 
  #[inline]

tests/mir-opt/inline/inline_generator.main.Inline.panic-abort.diff

@@ -7,12 +7,11 @@
  let mut _2: std::pin::Pin<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>;
  let mut _3: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8};
  let mut _4: {generator@$DIR/inline_generator.rs:16:5: 16:8};
-+ let mut _6: bool;
++ let mut _5: bool;
  scope 1 {
  debug _r => _1;
  }
 + scope 2 (inlined g) {
-+ let mut _5: {generator@$DIR/inline_generator.rs:16:5: 16:8};
 + }
 + scope 3 (inlined Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>::new) {
 + debug pointer => _3;
@@ -23,10 +22,10 @@
 + }
 + }
 + scope 6 (inlined g::{closure#0}) {
-+ debug a => _6;
-+ let mut _7: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8};
-+ let mut _8: u32;
-+ let mut _9: i32;
++ debug a => _5;
++ let mut _6: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8};
++ let mut _7: u32;
++ let mut _8: i32;
 + }
 
  bb0: {
@@ -35,28 +34,25 @@
  StorageLive(_3);
  StorageLive(_4);
 - _4 = g() -> [return: bb1, unwind unreachable];
-+ StorageLive(_5);
-+ _5 = {generator@$DIR/inline_generator.rs:16:5: 16:8 (#0)};
-+ _4 = move (_5 as subtype {generator@$DIR/inline_generator.rs:16:5: 16:8});
-+ StorageDead(_5);
++ _4 = {generator@$DIR/inline_generator.rs:16:5: 16:8 (#0)};
 + _3 = &mut _4;
 + _2 = Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}> { pointer: move _3 };
 + StorageDead(_3);
++ StorageLive(_5);
++ _5 = const false;
 + StorageLive(_6);
-+ _6 = const false;
 + StorageLive(_7);
-+ StorageLive(_8);
-+ _7 = (_2.0: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8});
-+ _8 = discriminant((*_7));
-+ switchInt(move _8) -> [0: bb3, 1: bb7, 3: bb8, otherwise: bb9];
++ _6 = (_2.0: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8});
++ _7 = discriminant((*_6));
++ switchInt(move _7) -> [0: bb3, 1: bb7, 3: bb8, otherwise: bb9];
  }
 
  bb1: {
 - _3 = &mut _4;
 - _2 = Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>::new(move _3) -> [return: bb2, unwind unreachable];
-+ StorageDead(_8);
 + StorageDead(_7);
 + StorageDead(_6);
++ StorageDead(_5);
 + StorageDead(_2);
 + drop(_4) -> [return: bb2, unwind unreachable];
  }
@@ -73,27 +69,27 @@
  bb3: {
 - StorageDead(_2);
 - drop(_4) -> [return: bb4, unwind unreachable];
-+ StorageLive(_9);
-+ switchInt(_6) -> [0: bb4, otherwise: bb5];
++ StorageLive(_8);
++ switchInt(_5) -> [0: bb4, otherwise: bb5];
  }
 
  bb4: {
 - StorageDead(_4);
 - _0 = const ();
 - StorageDead(_1);
 - return;
-+ _9 = const 13_i32;
++ _8 = const 13_i32;
 + goto -> bb6;
 + }
 + 
 + bb5: {
-+ _9 = const 7_i32;
++ _8 = const 7_i32;
 + goto -> bb6;
 + }
 + 
 + bb6: {
-+ _1 = GeneratorState::<i32, bool>::Yielded(move _9);
-+ discriminant((*_7)) = 3;
++ _1 = GeneratorState::<i32, bool>::Yielded(move _8);
++ discriminant((*_6)) = 3;
 + goto -> bb1;
 + }
 + 
@@ -102,10 +98,10 @@
 + }
 + 
 + bb8: {
-+ StorageLive(_9);
-+ StorageDead(_9);
-+ _1 = GeneratorState::<i32, bool>::Complete(_6);
-+ discriminant((*_7)) = 1;
++ StorageLive(_8);
++ StorageDead(_8);
++ _1 = GeneratorState::<i32, bool>::Complete(_5);
++ discriminant((*_6)) = 1;
 + goto -> bb1;
 + }
 + 

tests/mir-opt/inline/inline_generator.main.Inline.panic-unwind.diff

@@ -7,12 +7,11 @@
  let mut _2: std::pin::Pin<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>;
  let mut _3: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8};
  let mut _4: {generator@$DIR/inline_generator.rs:16:5: 16:8};
-+ let mut _6: bool;
++ let mut _5: bool;
  scope 1 {
  debug _r => _1;
  }
 + scope 2 (inlined g) {
-+ let mut _5: {generator@$DIR/inline_generator.rs:16:5: 16:8};
 + }
 + scope 3 (inlined Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>::new) {
 + debug pointer => _3;
@@ -23,10 +22,10 @@
 + }
 + }
 + scope 6 (inlined g::{closure#0}) {
-+ debug a => _6;
-+ let mut _7: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8};
-+ let mut _8: u32;
-+ let mut _9: i32;
++ debug a => _5;
++ let mut _6: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8};
++ let mut _7: u32;
++ let mut _8: i32;
 + }
 
  bb0: {
@@ -38,10 +37,7 @@
 - }
 - 
 - bb1: {
-+ StorageLive(_5);
-+ _5 = {generator@$DIR/inline_generator.rs:16:5: 16:8 (#0)};
-+ _4 = move (_5 as subtype {generator@$DIR/inline_generator.rs:16:5: 16:8});
-+ StorageDead(_5);
++ _4 = {generator@$DIR/inline_generator.rs:16:5: 16:8 (#0)};
  _3 = &mut _4;
 - _2 = Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}>::new(move _3) -> [return: bb2, unwind: bb5];
 - }
@@ -50,20 +46,20 @@
 + _2 = Pin::<&mut {generator@$DIR/inline_generator.rs:16:5: 16:8}> { pointer: move _3 };
  StorageDead(_3);
 - _1 = <{generator@$DIR/inline_generator.rs:16:5: 16:8} as Generator<bool>>::resume(move _2, const false) -> [return: bb3, unwind: bb5];
++ StorageLive(_5);
++ _5 = const false;
 + StorageLive(_6);
-+ _6 = const false;
 + StorageLive(_7);
-+ StorageLive(_8);
-+ _7 = (_2.0: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8});
-+ _8 = discriminant((*_7));
-+ switchInt(move _8) -> [0: bb5, 1: bb9, 3: bb10, otherwise: bb11];
++ _6 = (_2.0: &mut {generator@$DIR/inline_generator.rs:16:5: 16:8});
++ _7 = discriminant((*_6));
++ switchInt(move _7) -> [0: bb5, 1: bb9, 3: bb10, otherwise: bb11];
  }
 
 - bb3: {
 + bb1: {
-+ StorageDead(_8);
 + StorageDead(_7);
 + StorageDead(_6);
++ StorageDead(_5);
  StorageDead(_2);
 - drop(_4) -> [return: bb4, unwind: bb6];
 + drop(_4) -> [return: bb2, unwind: bb4];
@@ -89,23 +85,23 @@
 + }
 + 
 + bb5: {
-+ StorageLive(_9);
-+ switchInt(_6) -> [0: bb6, otherwise: bb7];
++ StorageLive(_8);
++ switchInt(_5) -> [0: bb6, otherwise: bb7];
 + }
 + 
 + bb6: {
-+ _9 = const 13_i32;
++ _8 = const 13_i32;
 + goto -> bb8;
 + }
 + 
 + bb7: {
-+ _9 = const 7_i32;
++ _8 = const 7_i32;
 + goto -> bb8;
 + }
 + 
 + bb8: {
-+ _1 = GeneratorState::<i32, bool>::Yielded(move _9);
-+ discriminant((*_7)) = 3;
++ _1 = GeneratorState::<i32, bool>::Yielded(move _8);
++ discriminant((*_6)) = 3;
 + goto -> bb1;
 + }
 + 
@@ -114,10 +110,10 @@
 + }
 + 
 + bb10: {
-+ StorageLive(_9);
-+ StorageDead(_9);
-+ _1 = GeneratorState::<i32, bool>::Complete(_6);
-+ discriminant((*_7)) = 1;
++ StorageLive(_8);
++ StorageDead(_8);
++ _1 = GeneratorState::<i32, bool>::Complete(_5);
++ discriminant((*_6)) = 1;
 + goto -> bb1;
 + }
 + 

tests/ui/impl-trait/impl-subtyper.rs

@@ -0,0 +1,18 @@
+// check-pass
+
+#![crate_type = "lib"]
+fn checkpoints() -> impl Iterator {
+ Some(()).iter().flat_map(|_| std::iter::once(()))
+}
+
+fn block_checkpoints() -> impl Iterator {
+ checkpoints()
+}
+
+fn iter_raw() -> impl Iterator {
+ let mut iter = block_checkpoints();
+
+ (0..9).map(move |_| {
+ iter.next();
+ })
+}

tests/ui/impl-trait/impl-subtyper2.rs

@@ -0,0 +1,7 @@
+// check-pass
+
+fn ages() -> Option<impl Iterator> {
+ None::<std::slice::Iter<()>>
+}
+
+fn main(){}

tests/ui/type-alias-impl-trait/normalize-alias-type.rs

@@ -0,0 +1,32 @@
+// check-pass
+// compile-flags: -Z mir-opt-level=3
+#![feature(type_alias_impl_trait)]
+#![crate_type = "lib"]
+pub trait Tr {
+ fn get(&self) -> u32;
+}
+
+impl Tr for (u32,) {
+ #[inline]
+ fn get(&self) -> u32 { self.0 }
+}
+
+pub fn tr1() -> impl Tr {
+ (32,)
+}
+
+pub fn tr2() -> impl Tr {
+ struct Inner {
+ x: X,
+ }
+ type X = impl Tr;
+ impl Tr for Inner {
+ fn get(&self) -> u32 {
+ self.x.get()
+ }
+ }
+
+ Inner {
+ x: tr1(),
+ }
+}

tests/ui/type-alias-impl-trait/tait-normalize.rs

@@ -0,0 +1,14 @@
+// check-pass
+
+#![feature(type_alias_impl_trait)]
+
+fn enum_upvar() {
+ type T = impl Copy;
+ let foo: T = Some((1u32, 2u32));
+ let x = move || match foo {
+ None => (),
+ Some((a, b)) => (),
+ };
+}
+
+fn main(){}

tests/ui/type/subtyping-opaque-type.rs

@@ -0,0 +1,19 @@
+// check-pass
+// compile-flags: -Zvalidate-mir
+trait Duh {}
+
+impl Duh for i32 {}
+
+trait Trait {
+ type Assoc: Duh;
+}
+
+impl<R: Duh, F: FnMut() -> R> Trait for F {
+ type Assoc = R;
+}
+
+fn foo() -> impl Trait<Assoc = impl Send> {
+ || 42
+}
+
+fn main() {}