Allow destructuring opaque types in their defining scopes #98582

oli-obk · 2022-06-27T16:33:59Z

Before this PR, the following code snippet failed with an incomprehensible error, and similar code just ICEd in mir borrowck.

    type T = impl Copy;
    let foo: T = (1u32, 2u32);
    let (a, b) = foo;

The problem was that the last line created MIR projections of the form foo.0 and foo.1, but foo's type is T, which doesn't have fields (only its hidden type does). But the pattern supplies enough type information (a tuple of two different inference types) to bind a hidden type.

rust-highfive · 2022-06-27T16:34:04Z

Some changes occured to the CTFE / Miri engine

cc @rust-lang/miri

rust-highfive · 2022-06-27T16:34:05Z

r? @nagisa

(rust-highfive has picked a reviewer for you, use r? to override)

bors · 2022-06-27T19:58:41Z

☔ The latest upstream changes (presumably #98566) made this pull request unmergeable. Please resolve the merge conflicts.

rustbot · 2022-06-28T11:19:47Z

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

Some changes occurred to MIR optimizations

cc @rust-lang/mir-opt

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

bors · 2022-06-30T07:22:55Z

☔ The latest upstream changes (presumably #98649) made this pull request unmergeable. Please resolve the merge conflicts.

oli-obk · 2022-06-30T07:24:33Z

cc @rust-lang/wg-mir-opt this is solely a MIR building/mir-borrowck concern, any takers?

bors · 2022-07-13T05:36:14Z

☔ The latest upstream changes (presumably #99101) made this pull request unmergeable. Please resolve the merge conflicts.

…site

…it ever happened

…aque types

oli-obk · 2022-07-15T16:05:15Z

r? rust-lang/compiler-team

oli-obk · 2022-07-15T16:07:50Z

r? compiler-team

estebank

@bors r+

src/test/ui/type-alias-impl-trait/issue-96572-unconstrained.rs

estebank · 2022-07-15T19:29:38Z

src/test/ui/type-alias-impl-trait/issue-96572-unconstrained-only-pattern-rpit.rs

+#[allow(unconditional_recursion)]
+fn foo(b: bool) -> impl Copy {
+    let (mut x, mut y) = foo(false);
+    x = 42;
+    y = "foo";
+    if b {
+        panic!()
+    } else {
+        foo(true)
+    }
+}


This looks like a bug on the lint?

estebank · 2022-07-15T20:37:50Z

compiler/rustc_mir_build/src/build/matches/test.rs

-        {
-            place = test_place_builder.into_place(self.tcx, self.typeck_results);
-        } else {
-            return;


So the early return is no longer needed because of the changes in the files above?

into_place ICEs if try_upvars_resolved would have returned Err. So this early return was always dead code as I could not figure out when it would ever happen and nothing in our test suite actually hit it.

estebank · 2022-07-15T20:39:20Z

compiler/rustc_mir_build/src/thir/pattern/usefulness.rs

+        // Opaque types can't get destructured/split, but the patterns can
+        // actually hint at hidden types, so we use the patterns' types instead.
+        if let ty::Opaque(..) = v.head().ty().kind() {
+            if let Some(row) = rows.first() {
+                ty = row.head().ty();
+            }
+        }


I'm guessing this is the meat of this change to get things working.

estebank · 2022-07-16T02:46:33Z

@bors r+

bors · 2022-07-16T02:46:35Z

📌 Commit 57e9f7a has been approved by estebank

It is now in the queue for this repository.

…askrgr Rollup of 10 pull requests Successful merges: - rust-lang#98582 (Allow destructuring opaque types in their defining scopes) - rust-lang#99213 (migrate some of `rustc_passes::check_attr`'s diagnostics and derive improvements) - rust-lang#99258 (Provide structured suggestion for dropped temp value) - rust-lang#99259 (interpret/visitor: support visiting with a PlaceTy) - rust-lang#99287 ([rustdoc-json] JSON no longer inlines) - rust-lang#99290 (Revert "Highlight conflicting param-env candidates") - rust-lang#99316 (docs: add missing word) - rust-lang#99317 (Borrow Vec<T, A> as [T]) - rust-lang#99323 (Fix flakyness of GUI tests) - rust-lang#99342 (Avoid some `Symbol` to `String` conversions) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup

…e_type, r=estebank" This reverts commit 6f8fb91, reversing changes made to 7210e46.

Revert "Rollup merge of rust-lang#98582 - oli-obk:unconstrained_opaque_type, r… …=estebank" This reverts commit 6f8fb91, reversing changes made to 7210e46. r? `@ghost` rebase of rust-lang#99368

…e_type, r=estebank" This reverts commit 6f8fb91, reversing changes made to 7210e46.

…rors Some `is_useful` cleanups rust-lang#98582 was reverted because it was a perf regression. rust-lang#99806 reintroduces the changes, but this PR picks individual ones that have no regressions.

…ed_opaque_type, r=estebank"" This reverts commit 4a742a6.

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Jun 27, 2022

rust-highfive assigned nagisa Jun 27, 2022

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 27, 2022

oli-obk force-pushed the unconstrained_opaque_type branch from d9d3674 to 9399ae1 Compare June 28, 2022 13:50

oli-obk marked this pull request as ready for review June 28, 2022 13:50

oli-obk force-pushed the unconstrained_opaque_type branch from 9399ae1 to 57d011d Compare July 12, 2022 09:16

oli-obk added 11 commits July 15, 2022 15:49

Introduce opaque type to hidden type projection

84a444a

Add some tracing instrumentation

a034446

Pass one argument instead of fetching two fields of it at every call …

eeb1033

…site

Remove early return that would likely have caused miscompilations if …

7a8a048

…it ever happened

Reuse a helper method instead of manually rolling it

0c6918f

Some tracing helpers

12457f8

Allow destructuring opaque types, since the patterns constrain the op…

728c7e8

…aque types

Make destructuring a defining use

6b33d5b

Revert a hack that only ever worked on level deep

ea68ce7

Move constructor into the branch that actually uses it

92e470a

Infer wildcard type from other patterns at every pattern level

57e9f7a

oli-obk force-pushed the unconstrained_opaque_type branch from 57d011d to 57e9f7a Compare July 15, 2022 16:01

rust-highfive assigned estebank and unassigned nagisa Jul 15, 2022

estebank approved these changes Jul 16, 2022

View reviewed changes

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 Jul 16, 2022

matthiaskrgr mentioned this pull request Jul 16, 2022

Rollup of 10 pull requests #99346

Merged

bors merged commit 6f8fb91 into rust-lang:master Jul 16, 2022

rustbot added this to the 1.64.0 milestone Jul 16, 2022

oli-obk deleted the unconstrained_opaque_type branch July 17, 2022 08:12

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Jul 17, 2022

Revert "Rollup merge of rust-lang#98582 - oli-obk:unconstrained_opaqu…

63d3cea

…e_type, r=estebank" This reverts commit 6f8fb91, reversing changes made to 7210e46.

oli-obk mentioned this pull request Jul 18, 2022

Revert Allow destructuring opaque types in their defining scopes #99368

Closed

oli-obk added a commit to oli-obk/rust that referenced this pull request Jul 20, 2022

Revert "Rollup merge of rust-lang#98582 - oli-obk:unconstrained_opaqu…

4a742a6

…e_type, r=estebank" This reverts commit 6f8fb91, reversing changes made to 7210e46.

celinval mentioned this pull request Jul 21, 2022

Update toolchain to nightly-2022-07-19 model-checking/kani#1399

Merged

4 tasks

JohnTitor mentioned this pull request Jul 21, 2022

TAIT: "unconstrained opaque type" error even if it's constrained #96572

Closed

cr1901 mentioned this pull request Jul 24, 2022

Binary size regression on msp430 due to #98582 #99685

Closed

JohnTitor pushed a commit to JohnTitor/rust that referenced this pull request Jul 26, 2022

Revert "Rollup merge of rust-lang#98582 - oli-obk:unconstrained_opaqu…

22a0a2e

…e_type, r=estebank" This reverts commit 6f8fb91, reversing changes made to 7210e46.

oli-obk mentioned this pull request Jul 28, 2022

Some is_useful cleanups #99843

Merged

flip1995 pushed a commit to flip1995/rust that referenced this pull request Jul 28, 2022

Revert "Rollup merge of rust-lang#98582 - oli-obk:unconstrained_opaqu…

bcd2241

…e_type, r=estebank" This reverts commit 6f8fb91, reversing changes made to 7210e46.

oli-obk added a commit to oli-obk/rust that referenced this pull request Sep 16, 2022

Revert "Revert "Rollup merge of rust-lang#98582 - oli-obk:unconstrain…

40e2de8

…ed_opaque_type, r=estebank"" This reverts commit 4a742a6.

flip1995 pushed a commit to flip1995/rust that referenced this pull request Oct 6, 2022

Revert "Revert "Rollup merge of rust-lang#98582 - oli-obk:unconstrain…

c2e9c99

…ed_opaque_type, r=estebank"" This reverts commit 4a742a6.

tedinski mentioned this pull request Oct 14, 2022

Update Kani to Rust nightly-2022-10-11 model-checking/kani#1788

Merged

4 tasks

bjorn3 pushed a commit to bjorn3/rust that referenced this pull request Oct 23, 2022

Revert "Revert "Rollup merge of rust-lang#98582 - oli-obk:unconstrain…

93af5f5

…ed_opaque_type, r=estebank"" This reverts commit 4a742a6.

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Allow destructuring opaque types in their defining scopes #98582

Allow destructuring opaque types in their defining scopes #98582

oli-obk commented Jun 27, 2022 •

edited

Loading

rust-highfive commented Jun 27, 2022

rust-highfive commented Jun 27, 2022

bors commented Jun 27, 2022

rustbot commented Jun 28, 2022

bors commented Jun 30, 2022

oli-obk commented Jun 30, 2022 •

edited

Loading

bors commented Jul 13, 2022

oli-obk commented Jul 15, 2022 •

edited

Loading

oli-obk commented Jul 15, 2022

estebank left a comment

estebank Jul 15, 2022

estebank Jul 15, 2022

oli-obk Jul 17, 2022

estebank Jul 15, 2022

estebank commented Jul 16, 2022

bors commented Jul 16, 2022

Allow destructuring opaque types in their defining scopes #98582

Allow destructuring opaque types in their defining scopes #98582

Conversation

oli-obk commented Jun 27, 2022 • edited Loading

rust-highfive commented Jun 27, 2022

rust-highfive commented Jun 27, 2022

bors commented Jun 27, 2022

rustbot commented Jun 28, 2022

bors commented Jun 30, 2022

oli-obk commented Jun 30, 2022 • edited Loading

bors commented Jul 13, 2022

oli-obk commented Jul 15, 2022 • edited Loading

oli-obk commented Jul 15, 2022

estebank left a comment

Choose a reason for hiding this comment

estebank Jul 15, 2022

Choose a reason for hiding this comment

estebank Jul 15, 2022

Choose a reason for hiding this comment

oli-obk Jul 17, 2022

Choose a reason for hiding this comment

estebank Jul 15, 2022

Choose a reason for hiding this comment

estebank commented Jul 16, 2022

bors commented Jul 16, 2022

oli-obk commented Jun 27, 2022 •

edited

Loading

oli-obk commented Jun 30, 2022 •

edited

Loading

oli-obk commented Jul 15, 2022 •

edited

Loading