-
Notifications
You must be signed in to change notification settings - Fork 12.8k
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Inconsistent error when using bindings after @
#120210
Labels
C-bug
Category: This is a bug.
F-bindings_after_at
`#![feature(bindings_after_at)]`
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
Comments
Nadrieril
added
C-bug
Category: This is a bug.
F-bindings_after_at
`#![feature(bindings_after_at)]`
labels
Jan 21, 2024
rustbot
added
the
needs-triage
This issue may need triage. Remove it if it has been sufficiently triaged.
label
Jan 21, 2024
fmease
added
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
and removed
needs-triage
This issue may need triage. Remove it if it has been sufficiently triaged.
labels
Jan 23, 2024
matthiaskrgr
added a commit
to matthiaskrgr/rust
that referenced
this issue
Feb 3, 2024
match lowering: consistently lower bindings deepest-first Currently when lowering match expressions to MIR, we do a funny little dance with the order of bindings. I attempt to explain it in the third commit: we handle refutable (i.e. needing a test) patterns differently than irrefutable ones. This leads to inconsistencies, as reported in rust-lang#120210. The reason we need a dance at all is for situations like: ```rust fn foo1(x: NonCopyStruct) { let y @ NonCopyStruct { copy_field: z } = x; // the above should turn into let z = x.copy_field; let y = x; } ``` Here the `y `@`` binding will move out of `x`, so we need to copy the field first. I believe that the inconsistency came about when we fixed rust-lang#69971, and didn't notice that the fix didn't extend to refutable patterns. My guess then is that ordering bindings by "deepest-first, otherwise source order" is a sound choice. This PR implements that (at least I hope, match lowering is hard to follow 🥲). Fixes rust-lang#120210 r? `@oli-obk` since you merged the original fix to rust-lang#69971 cc `@matthewjasper`
matthiaskrgr
added a commit
to matthiaskrgr/rust
that referenced
this issue
Feb 3, 2024
match lowering: consistently lower bindings deepest-first Currently when lowering match expressions to MIR, we do a funny little dance with the order of bindings. I attempt to explain it in the third commit: we handle refutable (i.e. needing a test) patterns differently than irrefutable ones. This leads to inconsistencies, as reported in rust-lang#120210. The reason we need a dance at all is for situations like: ```rust fn foo1(x: NonCopyStruct) { let y @ NonCopyStruct { copy_field: z } = x; // the above should turn into let z = x.copy_field; let y = x; } ``` Here the `y ``@``` binding will move out of `x`, so we need to copy the field first. I believe that the inconsistency came about when we fixed rust-lang#69971, and didn't notice that the fix didn't extend to refutable patterns. My guess then is that ordering bindings by "deepest-first, otherwise source order" is a sound choice. This PR implements that (at least I hope, match lowering is hard to follow 🥲). Fixes rust-lang#120210 r? ``@oli-obk`` since you merged the original fix to rust-lang#69971 cc ``@matthewjasper``
matthiaskrgr
added a commit
to matthiaskrgr/rust
that referenced
this issue
Feb 5, 2024
match lowering: consistently lower bindings deepest-first Currently when lowering match expressions to MIR, we do a funny little dance with the order of bindings. I attempt to explain it in the third commit: we handle refutable (i.e. needing a test) patterns differently than irrefutable ones. This leads to inconsistencies, as reported in rust-lang#120210. The reason we need a dance at all is for situations like: ```rust fn foo1(x: NonCopyStruct) { let y @ NonCopyStruct { copy_field: z } = x; // the above should turn into let z = x.copy_field; let y = x; } ``` Here the `y ```@```` binding will move out of `x`, so we need to copy the field first. I believe that the inconsistency came about when we fixed rust-lang#69971, and didn't notice that the fix didn't extend to refutable patterns. My guess then is that ordering bindings by "deepest-first, otherwise source order" is a sound choice. This PR implements that (at least I hope, match lowering is hard to follow 🥲). Fixes rust-lang#120210 r? ```@oli-obk``` since you merged the original fix to rust-lang#69971 cc ```@matthewjasper```
matthiaskrgr
added a commit
to matthiaskrgr/rust
that referenced
this issue
Feb 5, 2024
match lowering: consistently lower bindings deepest-first Currently when lowering match expressions to MIR, we do a funny little dance with the order of bindings. I attempt to explain it in the third commit: we handle refutable (i.e. needing a test) patterns differently than irrefutable ones. This leads to inconsistencies, as reported in rust-lang#120210. The reason we need a dance at all is for situations like: ```rust fn foo1(x: NonCopyStruct) { let y @ NonCopyStruct { copy_field: z } = x; // the above should turn into let z = x.copy_field; let y = x; } ``` Here the `y ````@````` binding will move out of `x`, so we need to copy the field first. I believe that the inconsistency came about when we fixed rust-lang#69971, and didn't notice that the fix didn't extend to refutable patterns. My guess then is that ordering bindings by "deepest-first, otherwise source order" is a sound choice. This PR implements that (at least I hope, match lowering is hard to follow 🥲). Fixes rust-lang#120210 r? ````@oli-obk```` since you merged the original fix to rust-lang#69971 cc ````@matthewjasper````
matthiaskrgr
added a commit
to matthiaskrgr/rust
that referenced
this issue
Feb 7, 2024
match lowering: consistently lower bindings deepest-first Currently when lowering match expressions to MIR, we do a funny little dance with the order of bindings. I attempt to explain it in the third commit: we handle refutable (i.e. needing a test) patterns differently than irrefutable ones. This leads to inconsistencies, as reported in rust-lang#120210. The reason we need a dance at all is for situations like: ```rust fn foo1(x: NonCopyStruct) { let y @ NonCopyStruct { copy_field: z } = x; // the above should turn into let z = x.copy_field; let y = x; } ``` Here the `y `````@`````` binding will move out of `x`, so we need to copy the field first. I believe that the inconsistency came about when we fixed rust-lang#69971, and didn't notice that the fix didn't extend to refutable patterns. My guess then is that ordering bindings by "deepest-first, otherwise source order" is a sound choice. This PR implements that (at least I hope, match lowering is hard to follow 🥲). Fixes rust-lang#120210 r? `````@oli-obk````` since you merged the original fix to rust-lang#69971 cc `````@matthewjasper`````
matthiaskrgr
added a commit
to matthiaskrgr/rust
that referenced
this issue
Feb 8, 2024
match lowering: consistently lower bindings deepest-first Currently when lowering match expressions to MIR, we do a funny little dance with the order of bindings. I attempt to explain it in the third commit: we handle refutable (i.e. needing a test) patterns differently than irrefutable ones. This leads to inconsistencies, as reported in rust-lang#120210. The reason we need a dance at all is for situations like: ```rust fn foo1(x: NonCopyStruct) { let y @ NonCopyStruct { copy_field: z } = x; // the above should turn into let z = x.copy_field; let y = x; } ``` Here the `y ``````@``````` binding will move out of `x`, so we need to copy the field first. I believe that the inconsistency came about when we fixed rust-lang#69971, and didn't notice that the fix didn't extend to refutable patterns. My guess then is that ordering bindings by "deepest-first, otherwise source order" is a sound choice. This PR implements that (at least I hope, match lowering is hard to follow 🥲). Fixes rust-lang#120210 r? ``````@oli-obk`````` since you merged the original fix to rust-lang#69971 cc ``````@matthewjasper``````
rust-timer
added a commit
to rust-lang-ci/rust
that referenced
this issue
Feb 8, 2024
Rollup merge of rust-lang#120214 - Nadrieril:fix-120210, r=pnkfelix match lowering: consistently lower bindings deepest-first Currently when lowering match expressions to MIR, we do a funny little dance with the order of bindings. I attempt to explain it in the third commit: we handle refutable (i.e. needing a test) patterns differently than irrefutable ones. This leads to inconsistencies, as reported in rust-lang#120210. The reason we need a dance at all is for situations like: ```rust fn foo1(x: NonCopyStruct) { let y @ NonCopyStruct { copy_field: z } = x; // the above should turn into let z = x.copy_field; let y = x; } ``` Here the `y ```````@```````` binding will move out of `x`, so we need to copy the field first. I believe that the inconsistency came about when we fixed rust-lang#69971, and didn't notice that the fix didn't extend to refutable patterns. My guess then is that ordering bindings by "deepest-first, otherwise source order" is a sound choice. This PR implements that (at least I hope, match lowering is hard to follow 🥲). Fixes rust-lang#120210 r? ```````@oli-obk``````` since you merged the original fix to rust-lang#69971 cc ```````@matthewjasper```````
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Labels
C-bug
Category: This is a bug.
F-bindings_after_at
`#![feature(bindings_after_at)]`
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
In the following, the first case compiles (playground) and the second errors (playground). The only difference is adding a variant to the enum.
Error:
This is an extension to #69971. I discovered this while poking at the match lowering code. Essentially, #69971 was accidentally only fixed for the case of irrefutable patterns, since patterns that require a test go through a different code path.
The text was updated successfully, but these errors were encountered: