2229: Fix issues with move closures and mutability by arora-aman · Pull Request #80092 · rust-lang/rust

arora-aman · 2020-12-16T20:41:19Z

This PR fixes two issues when feature capture_disjoint_fields is used.

Can't mutate using a mutable reference
Move closures try to move value out through a reference.

To do so, we

Compute the mutability of the capture and store it as part of the CapturedPlace that is written in TypeckResults
Restrict capture precision. Note this is temporary for now, to allow the feature to be used with move closures and ByValue captures and might change depending on discussions with the lang team.
- No Derefs are captured for ByValue captures, since that will result in value behind a reference getting moved.
- No projections are applied to raw pointers since these require unsafe blocks. We capture
  them completely.

r? @nikomatsakis

compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs

arora-aman · 2020-12-16T20:46:04Z

src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm-borrow.rs

I would have expected us to not try read the place z on its own. When the feature isn't enabled we only read z.0.0.0.

Debug logs from the report_mutability_error when the feature is enabled.

DEBUG rustc_mir::borrow_check::diagnostics::mutability_errors report_mutability_error: access_place_desc=Some("z") .... DEBUG rustc_mir::borrow_check::diagnostics::mutability_errors report_mutability_error: access_place_desc=Some("z.0.0.0")

This is definitely not the error message we want-- we'd like the error to be reported on z.0.0.0, right? I think this may be related to my comment about the used_mut_upvars but I'm not 100% sure.

compiler/rustc_typeck/src/check/upvar.rs

compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs

arora-aman · 2020-12-16T20:57:12Z

src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm-borrow.rs

I hack around this error in a later commit

compiler/rustc_mir/src/borrow_check/mod.rs

nikomatsakis

First round of comments. I don't quite understand why that error message is showing up on the wrong line in the one case you highlighted.

nikomatsakis · 2020-12-17T10:39:30Z

compiler/rustc_mir/src/borrow_check/mod.rs

I think this is maybe missing a case -- if we capture a deref of an &mut. Also, I don't think that (a) is distinct from (b).

nikomatsakis · 2020-12-17T10:40:04Z

compiler/rustc_mir/src/borrow_check/mod.rs

To handle the deref of &mut` case, we could check here if

the projection is a deref

the type of the place_ref is an &mut

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

nikomatsakis · 2020-12-17T10:43:11Z

compiler/rustc_typeck/src/check/upvar.rs

I would add ty::Adt with an assertion that this is a bug, and then make _ => bug!("deref of unexpected pointer type {:?}", pointer_ty.kind()) or something like that

I'm assuming you meant Adt(boxed)

compiler/rustc_typeck/src/check/upvar.rs

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

nikomatsakis · 2020-12-17T10:48:43Z

src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm-borrow.rs

This is definitely not the error message we want-- we'd like the error to be reported on z.0.0.0, right? I think this may be related to my comment about the used_mut_upvars but I'm not 100% sure.

src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm.rs

compiler/rustc_typeck/src/check/upvar.rs

rust-log-analyzer · 2020-12-24T07:23:25Z

The job x86_64-gnu-llvm-9 failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

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---
i................................................................................................... 11200/11208
........
failures:

---- [ui] ui/closures/2229_closure_analysis/by_value.rs stdout ----

1 error[E0658]: attributes on expressions are experimental
-   --> $DIR/by_value.rs:20:13
+   --> $DIR/by_value.rs:22:13
+   --> $DIR/by_value.rs:22:13
3    |
4 LL |     let c = #[rustc_capture_analysis]

17    = note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
18 
18 
19 error: First Pass analysis includes:
-   --> $DIR/by_value.rs:23:5
+   --> $DIR/by_value.rs:25:5
22 LL | /     || {
23 LL | |

29    | |_____^
29    | |_____^
30    |
31 note: Capturing t[(0, 0),Deref,(0, 0)] -> ByValue
-   --> $DIR/by_value.rs:26:17
+   --> $DIR/by_value.rs:28:17
34 LL |         let p = t.0.0;
35    |                 ^^^^^


36 note: Capturing t[(1, 0)] -> ImmBorrow
-   --> $DIR/by_value.rs:29:29
+   --> $DIR/by_value.rs:31:29
38    |
39 LL |         println!("{} {:?}", t.1, p);

41 
41 
42 error: Min Capture analysis includes:
-   --> $DIR/by_value.rs:23:5
+   --> $DIR/by_value.rs:25:5
45 LL | /     || {
46 LL | |

52    | |_____^
52    | |_____^
53    |
54 note: Min Capture t[(0, 0)] -> ByValue
-   --> $DIR/by_value.rs:26:17
+   --> $DIR/by_value.rs:28:17
57 LL |         let p = t.0.0;
58    |                 ^^^^^


59 note: Min Capture t[(1, 0)] -> ImmBorrow
-   --> $DIR/by_value.rs:29:29
+   --> $DIR/by_value.rs:31:29
61    |
62 LL |         println!("{} {:?}", t.1, p);


The actual stderr differed from the expected stderr.
The actual stderr differed from the expected stderr.
Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/closures/2229_closure_analysis/by_value/by_value.stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args closures/2229_closure_analysis/by_value.rs`
error: 1 errors occurred comparing output.
status: exit code: 1
status: exit code: 1
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zemit-future-incompat-report" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/closures/2229_closure_analysis/by_value" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/closures/2229_closure_analysis/by_value/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
error[E0658]: attributes on expressions are experimental
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:22:13
   |
LL |     let c = #[rustc_capture_analysis]
   |
   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable

warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:5:12
   |
LL | #![feature(capture_disjoint_fields)]
   |
   = note: `#[warn(incomplete_features)]` on by default
   = note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information


error: First Pass analysis includes:
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:25:5
LL | /     || {
LL | /     || {
LL | |     //~^ First Pass analysis includes:
LL | |     //~| Min Capture analysis includes:
LL | |         let p = t.0.0;
...  |
LL | |         //~| NOTE: Min Capture t[(1, 0)] -> ImmBorrow
LL | |     };
   |
   |
note: Capturing t[(0, 0),Deref,(0, 0)] -> ByValue
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:28:17
LL |         let p = t.0.0;
   |                 ^^^^^
   |                 ^^^^^
note: Capturing t[(1, 0)] -> ImmBorrow
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:31:29
   |
LL |         println!("{} {:?}", t.1, p);


error: Min Capture analysis includes:
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:25:5
LL | /     || {
LL | /     || {
LL | |     //~^ First Pass analysis includes:
LL | |     //~| Min Capture analysis includes:
LL | |         let p = t.0.0;
...  |
LL | |         //~| NOTE: Min Capture t[(1, 0)] -> ImmBorrow
LL | |     };
   |
   |
note: Min Capture t[(0, 0)] -> ByValue
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:28:17
LL |         let p = t.0.0;
   |                 ^^^^^
   |                 ^^^^^
note: Min Capture t[(1, 0)] -> ImmBorrow
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:31:29
   |
LL |         println!("{} {:?}", t.1, p);

error: aborting due to 3 previous errors; 1 warning emitted

For more information about this error, try `rustc --explain E0658`.
---

Some tests failed in compiletest suite=ui mode=ui host=x86_64-unknown-linux-gnu target=x86_64-unknown-linux-gnu


command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/ui" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--suite" "ui" "--mode" "ui" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-9/bin/FileCheck" "--nodejs" "/usr/bin/node" "--host-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python2.7" "--lldb-python" "/usr/bin/python2.7" "--gdb" "/usr/bin/gdb" "--quiet" "--llvm-version" "9.0.0" "--llvm-components" "aarch64 aarch64asmparser aarch64codegen aarch64desc aarch64disassembler aarch64info aarch64utils aggressiveinstcombine all all-targets amdgpu amdgpuasmparser amdgpucodegen amdgpudesc amdgpudisassembler amdgpuinfo amdgpuutils analysis arm armasmparser armcodegen armdesc armdisassembler arminfo armutils asmparser asmprinter avr avrasmparser avrcodegen avrdesc avrdisassembler avrinfo binaryformat bitreader bitstreamreader bitwriter bpf bpfasmparser bpfcodegen bpfdesc bpfdisassembler bpfinfo codegen core coroutines coverage debuginfocodeview debuginfodwarf debuginfogsym debuginfomsf debuginfopdb demangle dlltooldriver engine executionengine fuzzmutate globalisel hexagon hexagonasmparser hexagoncodegen hexagondesc hexagondisassembler hexagoninfo instcombine instrumentation interpreter ipo irreader jitlink lanai lanaiasmparser lanaicodegen lanaidesc lanaidisassembler lanaiinfo libdriver lineeditor linker lto mc mca mcdisassembler mcjit mcparser mips mipsasmparser mipscodegen mipsdesc mipsdisassembler mipsinfo mirparser msp430 msp430asmparser msp430codegen msp430desc msp430disassembler msp430info native nativecodegen nvptx nvptxcodegen nvptxdesc nvptxinfo objcarcopts object objectyaml option orcjit passes perfjitevents powerpc powerpcasmparser powerpccodegen powerpcdesc powerpcdisassembler powerpcinfo profiledata remarks riscv riscvasmparser riscvcodegen riscvdesc riscvdisassembler riscvinfo riscvutils runtimedyld scalaropts selectiondag sparc sparcasmparser sparccodegen sparcdesc sparcdisassembler sparcinfo support symbolize systemz systemzasmparser systemzcodegen systemzdesc systemzdisassembler systemzinfo tablegen target textapi transformutils vectorize webassembly webassemblyasmparser webassemblycodegen webassemblydesc webassemblydisassembler webassemblyinfo windowsmanifest x86 x86asmparser x86codegen x86desc x86disassembler x86info x86utils xcore xcorecodegen xcoredesc xcoredisassembler xcoreinfo xray" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"


failed to run: /checkout/obj/build/bootstrap/debug/bootstrap --stage 2 test --exclude src/tools/tidy
Build completed unsuccessfully in 0:17:31

rust-log-analyzer · 2020-12-24T10:16:31Z

The job x86_64-gnu-llvm-9 failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

i................................................................................................... 11200/11208
........
failures:

---- [ui] ui/closures/2229_closure_analysis/by_value.rs stdout ----

1 error[E0658]: attributes on expressions are experimental
-   --> $DIR/by_value.rs:20:13
+   --> $DIR/by_value.rs:22:13
+   --> $DIR/by_value.rs:22:13
3    |
4 LL |     let c = #[rustc_capture_analysis]


The actual stderr differed from the expected stderr.
The actual stderr differed from the expected stderr.
Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/closures/2229_closure_analysis/by_value/by_value.stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args closures/2229_closure_analysis/by_value.rs`
error: 1 errors occurred comparing output.
status: exit code: 1
status: exit code: 1
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zemit-future-incompat-report" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/closures/2229_closure_analysis/by_value" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/closures/2229_closure_analysis/by_value/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
error[E0658]: attributes on expressions are experimental
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:22:13
   |
LL |     let c = #[rustc_capture_analysis]
   |
   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable

warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:5:12
   |
LL | #![feature(capture_disjoint_fields)]
   |
   = note: `#[warn(incomplete_features)]` on by default
   = note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information


error: First Pass analysis includes:
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:25:5
LL | /     || {
LL | /     || {
LL | |     //~^ First Pass analysis includes:
LL | |     //~| Min Capture analysis includes:
LL | |         let p = t.0.0;
...  |
LL | |         //~| NOTE: Min Capture t[(1, 0)] -> ImmBorrow
LL | |     };
   |
   |
note: Capturing t[(0, 0),Deref,(0, 0)] -> ByValue
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:28:17
LL |         let p = t.0.0;
   |                 ^^^^^
   |                 ^^^^^
note: Capturing t[(1, 0)] -> ImmBorrow
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:31:29
   |
LL |         println!("{} {:?}", t.1, p);


error: Min Capture analysis includes:
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:25:5
LL | /     || {
LL | /     || {
LL | |     //~^ First Pass analysis includes:
LL | |     //~| Min Capture analysis includes:
LL | |         let p = t.0.0;
...  |
LL | |         //~| NOTE: Min Capture t[(1, 0)] -> ImmBorrow
LL | |     };
   |
   |
note: Min Capture t[(0, 0)] -> ByValue
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:28:17
LL |         let p = t.0.0;
   |                 ^^^^^
   |                 ^^^^^
note: Min Capture t[(1, 0)] -> ImmBorrow
  --> /checkout/src/test/ui/closures/2229_closure_analysis/by_value.rs:31:29
   |
LL |         println!("{} {:?}", t.1, p);

error: aborting due to 3 previous errors; 1 warning emitted

For more information about this error, try `rustc --explain E0658`.
---

Some tests failed in compiletest suite=ui mode=ui host=x86_64-unknown-linux-gnu target=x86_64-unknown-linux-gnu


command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/ui" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--suite" "ui" "--mode" "ui" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-9/bin/FileCheck" "--nodejs" "/usr/bin/node" "--host-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python2.7" "--lldb-python" "/usr/bin/python2.7" "--gdb" "/usr/bin/gdb" "--quiet" "--llvm-version" "9.0.0" "--llvm-components" "aarch64 aarch64asmparser aarch64codegen aarch64desc aarch64disassembler aarch64info aarch64utils aggressiveinstcombine all all-targets amdgpu amdgpuasmparser amdgpucodegen amdgpudesc amdgpudisassembler amdgpuinfo amdgpuutils analysis arm armasmparser armcodegen armdesc armdisassembler arminfo armutils asmparser asmprinter avr avrasmparser avrcodegen avrdesc avrdisassembler avrinfo binaryformat bitreader bitstreamreader bitwriter bpf bpfasmparser bpfcodegen bpfdesc bpfdisassembler bpfinfo codegen core coroutines coverage debuginfocodeview debuginfodwarf debuginfogsym debuginfomsf debuginfopdb demangle dlltooldriver engine executionengine fuzzmutate globalisel hexagon hexagonasmparser hexagoncodegen hexagondesc hexagondisassembler hexagoninfo instcombine instrumentation interpreter ipo irreader jitlink lanai lanaiasmparser lanaicodegen lanaidesc lanaidisassembler lanaiinfo libdriver lineeditor linker lto mc mca mcdisassembler mcjit mcparser mips mipsasmparser mipscodegen mipsdesc mipsdisassembler mipsinfo mirparser msp430 msp430asmparser msp430codegen msp430desc msp430disassembler msp430info native nativecodegen nvptx nvptxcodegen nvptxdesc nvptxinfo objcarcopts object objectyaml option orcjit passes perfjitevents powerpc powerpcasmparser powerpccodegen powerpcdesc powerpcdisassembler powerpcinfo profiledata remarks riscv riscvasmparser riscvcodegen riscvdesc riscvdisassembler riscvinfo riscvutils runtimedyld scalaropts selectiondag sparc sparcasmparser sparccodegen sparcdesc sparcdisassembler sparcinfo support symbolize systemz systemzasmparser systemzcodegen systemzdesc systemzdisassembler systemzinfo tablegen target textapi transformutils vectorize webassembly webassemblyasmparser webassemblycodegen webassemblydesc webassemblydisassembler webassemblyinfo windowsmanifest x86 x86asmparser x86codegen x86desc x86disassembler x86info x86utils xcore xcorecodegen xcoredesc xcoredisassembler xcoreinfo xray" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"


failed to run: /checkout/obj/build/bootstrap/debug/bootstrap --stage 2 test --exclude src/tools/tidy
Build completed unsuccessfully in 0:18:02

src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm.rs

arora-aman · 2020-12-19T21:40:14Z

compiler/rustc_typeck/src/check/upvar.rs

I'm assuming you meant Adt(boxed)

arora-aman · 2020-12-26T09:51:10Z

compiler/rustc_typeck/src/check/upvar.rs

I went with this approach here because either we need to do a checked_add or init unsafe_ptr_idx = usize::MAX - 1. compared to the two, this seemed clearer.

arora-aman · 2020-12-27T05:08:12Z

src/test/ui/closures/2229_closure_analysis/diagnostics/mut_ref.rs

This gets hacked away as well in a later commit.

arora-aman · 2020-12-27T05:08:20Z

src/test/ui/closures/2229_closure_analysis/diagnostics/mut_ref.rs

This gets hacked away as well in a later commit.

bors · 2020-12-30T13:10:10Z

☔ The latest upstream changes (presumably #80503) made this pull request unmergeable. Please resolve the merge conflicts.

arora-aman · 2020-12-31T23:43:08Z

Conflicts should be resolved now

bors · 2021-01-17T18:12:35Z

☔ The latest upstream changes (presumably #81113) made this pull request unmergeable. Please resolve the merge conflicts.

nikomatsakis · 2021-01-28T11:25:11Z

compiler/rustc_middle/src/ty/mod.rs

I love how you're adding comments here btw 😍

nikomatsakis · 2021-01-28T14:22:33Z

compiler/rustc_middle/src/ty/mod.rs

I'd like to see a comment here, something like

/// Returns the hir-id of the root variable for the captured place. e.g., if a.b.c was captured, would return the hir-id for a.

nikomatsakis · 2021-01-28T14:22:53Z

compiler/rustc_middle/src/ty/mod.rs

So happy to see added comments 😍

nikomatsakis · 2021-01-28T14:35:24Z

compiler/rustc_mir/src/borrow_check/mod.rs

Suggested change

// We have three possiblities here:

// We have three possibilities here:

nikomatsakis · 2021-01-28T14:35:37Z

compiler/rustc_mir/src/borrow_check/mod.rs

Suggested change

// c. Current body is a nested clsoure, and we are modifying path starting from

// c. Current body is a nested closure, and we are modifying a path starting from

nikomatsakis · 2021-01-28T14:44:07Z

@bors delegate+

Left a few nits but this looks good. @arora-aman, you wanted to make a final change as well, right? Feel free to r=nikomatsakis afterwards.

bors · 2021-01-28T14:44:09Z

✌️ @arora-aman can now approve this pull request

- No Derefs in move closure, this will result in value behind a reference getting moved. - No projections are applied to raw pointers, since these require unsafe blocks. We capture them completely. Motivations for these are recorded here: https://hackmd.io/71qq-IOpTNqzMkPpAI1dVg?view

When `capture_disjoint_fields` is not enabled, checking if the root variable binding is mutable would suffice. However with the feature enabled, the captured place might be mutable because it dereferences a mutable reference. This PR computes the mutability of each capture after capture analysis in rustc_typeck. We store this in `ty::CapturedPlace` and then use `ty::CapturedPlace::mutability` in mir_build and borrow_check.

arora-aman · 2021-01-29T22:08:08Z

@bors r=nikomatsakis

bors · 2021-01-29T22:08:10Z

📌 Commit 0f4bab2 has been approved by nikomatsakis

…ikomatsakis 2229: Fix issues with move closures and mutability This PR fixes two issues when feature `capture_disjoint_fields` is used. 1. Can't mutate using a mutable reference 2. Move closures try to move value out through a reference. To do so, we 1. Compute the mutability of the capture and store it as part of the `CapturedPlace` that is written in TypeckResults 2. Restrict capture precision. Note this is temporary for now, to allow the feature to be used with move closures and ByValue captures and might change depending on discussions with the lang team. - No Derefs are captured for ByValue captures, since that will result in value behind a reference getting moved. - No projections are applied to raw pointers since these require unsafe blocks. We capture them completely. r? `@nikomatsakis`

…as-schievink Rollup of 11 pull requests Successful merges: - rust-lang#80092 (2229: Fix issues with move closures and mutability) - rust-lang#80404 (Remove const_in_array_repeat) - rust-lang#81255 (Don't link with --export-dynamic on wasm32-wasi) - rust-lang#81480 (Add suggestion for nested fields) - rust-lang#81549 (Misc ip documentation fixes) - rust-lang#81566 (Add a test for rust-lang#71202) - rust-lang#81568 (Fix an old FIXME in redundant paren lint) - rust-lang#81571 (Fix typo in E0759) - rust-lang#81572 (Edit multiple error code Markdown files) - rust-lang#81589 (Fix small typo in string.rs) - rust-lang#81590 (Stabilize int_bits_const) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup

rust-highfive assigned nikomatsakis Dec 16, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Dec 16, 2020

arora-aman commented Dec 16, 2020

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compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs Outdated Show resolved Hide resolved

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arora-aman mentioned this pull request Dec 17, 2020

Compute mutability of closure captures sexxi-goose/rust#37

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nikomatsakis reviewed Dec 17, 2020

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arora-aman force-pushed the restrict_precision branch 2 times, most recently from dc7edd1 to e6efc89 Compare December 24, 2020 07:02

arora-aman force-pushed the restrict_precision branch from e6efc89 to fcff889 Compare December 24, 2020 09:55

arora-aman force-pushed the restrict_precision branch from fcff889 to d07335a Compare December 24, 2020 20:38

arora-aman commented Dec 26, 2020

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arora-aman commented Dec 27, 2020

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arora-aman mentioned this pull request Dec 29, 2020

Use hir::Place instead of Symbol in closure_kind_origin sexxi-goose/rust#36

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arora-aman force-pushed the restrict_precision branch from d07335a to 69ea484 Compare December 31, 2020 23:40

arora-aman force-pushed the restrict_precision branch from 69ea484 to 967c2b2 Compare January 12, 2021 19:54

nikomatsakis approved these changes Jan 28, 2021

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arora-aman added 5 commits January 29, 2021 15:37

Test cases for handling mutable references

1373f98

Test for restricting capture precision

0897db5

Fix unused 'mut' warning for capture's root variable

604cbdc

arora-aman added 4 commits January 29, 2021 15:37

Fix incorrect use mut diagnostics

c748f32

Add fixme for precise path diagnostics

ffd5327

Fix typos

fadf03e

Fixme for closure origin when reborrow is implemented

0f4bab2

arora-aman force-pushed the restrict_precision branch from 967c2b2 to 0f4bab2 Compare January 29, 2021 21:25

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jan 29, 2021

m-ou-se mentioned this pull request Jan 30, 2021

Rollup of 11 pull requests #81553

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jonas-schievink mentioned this pull request Jan 30, 2021

Rollup of 9 pull requests #81559

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jonas-schievink mentioned this pull request Jan 31, 2021

Rollup of 8 pull requests #81593

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This was referenced Jan 31, 2021

Rollup of 7 pull requests #81595

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Rollup of 11 pull requests #81596

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bors merged commit 7e3a8ec into rust-lang:master Feb 1, 2021

rustbot added this to the 1.51.0 milestone Feb 1, 2021

This was referenced Feb 1, 2021

Handle mutablity because of a mut reference rust-lang/project-rfc-2229#30

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Move out of reference in move closures rust-lang/project-rfc-2229#31

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Add lint for 2229 migrations #80629

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arora-aman mentioned this pull request Apr 6, 2021

Implement reborrow for closure captures #82007

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m-ou-se mentioned this pull request Sep 3, 2021

🎉 Rust 2021 celebration and thanks #88623

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	// We have three possiblities here:
	// We have three possibilities here:

	// c. Current body is a nested clsoure, and we are modifying path starting from
	// c. Current body is a nested closure, and we are modifying a path starting from

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