Rollup of 4 pull requests #97591

matthiaskrgr · 2022-05-31T18:18:13Z

Successful merges:

Put a bound on collection misbehavior #97316 (Put a bound on collection misbehavior)
alloc: remove repeated word in comment #97578 (alloc: remove repeated word in comment)
Add regression test for #71546 #97580 (Add regression test for Broken MIR on HRTB #71546)
Add a pointer to address cast kind #97582 (Add a pointer to address cast kind)

Failed merges:

r? @ghost
@rustbot modify labels: rollup

As currently written, when a logic error occurs in a collection's trait parameters, this allows *completely arbitrary* misbehavior, so long as it does not cause undefined behavior in std. However, because the extent of misbehavior is not specified, it is allowed for *any* code in std to start misbehaving in arbitrary ways which are not formally UB; consider the theoretical example of a global which gets set on an observed logic error. Because the misbehavior is only bound by not resulting in UB from safe APIs and the crate-level encapsulation boundary of all of std, this makes writing user unsafe code that utilizes std theoretically impossible, as it now relies on undocumented QOI that unrelated parts of std cannot be caused to misbehave by a misuse of std::collections APIs. In practice, this is a nonconcern, because std has reasonable QOI and an implementation that takes advantage of this freedom is essentially a malicious implementation and only compliant by the most langauage-lawyer reading of the documentation. To close this hole, we just add a small clause to the existing logic error paragraph that ensures that any misbehavior is limited to the collection which observed the logic error, making it more plausible to prove the soundness of user unsafe code. This is not meant to be formal; a formal refinement would likely need to mention that values derived from the collection can also misbehave after a logic error is observed, as well as define what it means to "observe" a logic error in the first place. This fix errs on the side of informality in order to close the hole without complicating a normal reading which can assume a reasonable nonmalicious QOI. See also [discussion on IRLO][1]. [1]: https://internals.rust-lang.org/t/using-std-collections-and-unsafe-anything-can-happen/16640

A pointer to address cast are often special-cased. Introduce a dedicated cast kind to make them easy distinguishable.

Co-authored-by: lcnr <[email protected]>

Linux's `checkpatch.pl` reports: ```txt rust-lang#42544: FILE: rust/alloc/vec/mod.rs:2692: WARNING: Possible repeated word: 'to' + // - Elements are :Copy so it's OK to to copy them, without doing ``` Signed-off-by: Miguel Ojeda <[email protected]>

Put a bound on collection misbehavior As currently written, when a logic error occurs in a collection's trait parameters, this allows *completely arbitrary* misbehavior, so long as it does not cause undefined behavior in std. However, because the extent of misbehavior is not specified, it is allowed for *any* code in std to start misbehaving in arbitrary ways which are not formally UB; consider the theoretical example of a global which gets set on an observed logic error. Because the misbehavior is only bound by not resulting in UB from safe APIs and the crate-level encapsulation boundary of all of std, this makes writing user unsafe code that utilizes std theoretically impossible, as it now relies on undocumented QOI (quality of implementation) that unrelated parts of std cannot be caused to misbehave by a misuse of std::collections APIs. In practice, this is a nonconcern, because std has reasonable QOI and an implementation that takes advantage of this freedom is essentially a malicious implementation and only compliant by the most langauage-lawyer reading of the documentation. To close this hole, we just add a small clause to the existing logic error paragraph that ensures that any misbehavior is limited to the collection which observed the logic error, making it more plausible to prove the soundness of user unsafe code. This is not meant to be formal; a formal refinement would likely need to mention that values derived from the collection can also misbehave after a logic error is observed, as well as define what it means to "observe" a logic error in the first place. This fix errs on the side of informality in order to close the hole without complicating a normal reading which can assume a reasonable nonmalicious QOI. See also [discussion on IRLO][1]. [1]: https://internals.rust-lang.org/t/using-std-collections-and-unsafe-anything-can-happen/16640 r? rust-lang/libs-api ``@rustbot`` label +T-libs-api -T-libs This technically adds a new guarantee to the documentation, though I argue as written it's one already implicitly provided.

alloc: remove repeated word in comment Linux's `checkpatch.pl` reports: ```txt rust-lang#42544: FILE: rust/alloc/vec/mod.rs:2692: WARNING: Possible repeated word: 'to' + // - Elements are :Copy so it's OK to to copy them, without doing ``` Signed-off-by: Miguel Ojeda <[email protected]>

…rrors Add regression test for rust-lang#71546 Closes rust-lang#71546 r? `@compiler-errors`

…-obk Add a pointer to address cast kind A pointer to address cast are often special-cased. Introduce a dedicated cast kind to make them easy distinguishable.

matthiaskrgr · 2022-05-31T18:18:32Z

@bors r+ rollup=never p=4

bors · 2022-05-31T18:18:34Z

📌 Commit c7dd5bc has been approved by matthiaskrgr

bors · 2022-05-31T20:40:31Z

⌛ Testing commit c7dd5bc with merge 83477a9c08131a77b51ac0d632635682be91bf9e...

bors · 2022-05-31T21:06:06Z

💔 Test failed - checks-actions

rust-log-analyzer · 2022-05-31T21:28:25Z

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

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


---- [ui (nll)] src/test/ui/borrowck/issue-71546.rs stdout ----
diff of stderr:

- error[E0310]: the associated type `<&'a V as IntoIterator>::Item` may not live long enough
+ error: higher-ranked lifetime error
3    |
4 LL |       let csv_str: String = value


7 LL | |         .map(|elem| elem.to_string())
9    |
9    |
-    = help: consider adding an explicit lifetime bound `<&'a V as IntoIterator>::Item: 'static`...
-    = note: ...so that the type `<&'a V as IntoIterator>::Item` will meet its required lifetime bounds...
- note: ...that is required by this bound
-   --> $DIR/issue-71546.rs:7:55
+    = note: could not prove for<'r> [closure@$DIR/issue-71546.rs:11:14: 11:37] well-formed
+ error: higher-ranked lifetime error
+   --> $DIR/issue-71546.rs:9:27
14    |
14    |
- LL |     for<'a> <&'a V as IntoIterator>::Item: ToString + 'static,
+ LL |       let csv_str: String = value
+    |  ___________________________^
+ LL | |         .into_iter()
+ LL | |         .into_iter()
+ LL | |         .map(|elem| elem.to_string())
+    |
+    |
+    = note: could not prove for<'r, 's> Map<<&'r V as IntoIterator>::IntoIter, [closure@$DIR/issue-71546.rs:11:14: 11:37]> well-formed
- error: aborting due to previous error
+ error: higher-ranked lifetime error
+   --> $DIR/issue-71546.rs:9:27
+    |
+    |
+ LL |       let csv_str: String = value
+    |  ___________________________^
+ LL | |         .into_iter()
+ LL | |         .map(|elem| elem.to_string())
+ LL | |         .collect::<String>();
+    |
+    |
+    = note: could not prove for<'r, 's> Map<<&'r V as IntoIterator>::IntoIter, [closure@$DIR/issue-71546.rs:11:14: 11:37]> well-formed
- For more information about this error, try `rustc --explain E0310`.
+ error: higher-ranked lifetime error
+   --> $DIR/issue-71546.rs:11:14
+    |
+    |
+ LL |         .map(|elem| elem.to_string())
+    |
+    |
+    = note: could not prove for<'a> <&'a V as IntoIterator>::Item: 'static
+ error: higher-ranked lifetime error
+   --> $DIR/issue-71546.rs:12:10
+    |
+    |
+ LL |         .collect::<String>();
+ 
+ error: aborting due to 5 previous errors
+ 
21 
21 


The actual stderr differed from the expected stderr.
Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/borrowck/issue-71546.nll/issue-71546.nll.stderr
To only update this specific test, also pass `--test-args borrowck/issue-71546.rs`

error: 1 errors occurred comparing output.
status: exit status: 1
status: exit status: 1
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/borrowck/issue-71546.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/borrowck/issue-71546.nll" "-Zborrowck=mir" "-A" "unused" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/borrowck/issue-71546.nll/auxiliary"
stdout: none
--- stderr -------------------------------
error: higher-ranked lifetime error
   |
   |
LL |       let csv_str: String = value //~ ERROR: the associated type `<&'a V as IntoIterator>::Item` may not live long enough
LL | |         .into_iter()
LL | |         .into_iter()
LL | |         .map(|elem| elem.to_string())
   |
   |
   = note: could not prove for<'r> [closure@/checkout/src/test/ui/borrowck/issue-71546.rs:11:14: 11:37] well-formed
error: higher-ranked lifetime error
  --> /checkout/src/test/ui/borrowck/issue-71546.rs:9:27
   |
   |
LL |       let csv_str: String = value //~ ERROR: the associated type `<&'a V as IntoIterator>::Item` may not live long enough
LL | |         .into_iter()
LL | |         .into_iter()
LL | |         .map(|elem| elem.to_string())
   |
   |
   = note: could not prove for<'r, 's> Map<<&'r V as IntoIterator>::IntoIter, [closure@/checkout/src/test/ui/borrowck/issue-71546.rs:11:14: 11:37]> well-formed
error: higher-ranked lifetime error
  --> /checkout/src/test/ui/borrowck/issue-71546.rs:9:27
   |
   |
LL |       let csv_str: String = value //~ ERROR: the associated type `<&'a V as IntoIterator>::Item` may not live long enough
LL | |         .into_iter()
LL | |         .into_iter()
LL | |         .map(|elem| elem.to_string())
LL | |         .collect::<String>();
   | |____________________________^
Some tests failed in compiletest suite=ui compare_mode=Nll mode=ui host=x86_64-unknown-linux-gnu target=x86_64-unknown-linux-gnu
   |
   = note: could not prove for<'r, 's> Map<<&'r V as IntoIterator>::IntoIter, [closure@/checkout/src/test/ui/borrowck/issue-71546.rs:11:14: 11:37]> well-formed
error: higher-ranked lifetime error
  --> /checkout/src/test/ui/borrowck/issue-71546.rs:11:14
   |
   |
LL |         .map(|elem| elem.to_string())
   |
   |
   = note: could not prove for<'a> <&'a V as IntoIterator>::Item: 'static
error: higher-ranked lifetime error
  --> /checkout/src/test/ui/borrowck/issue-71546.rs:12:10
   |
   |
LL |         .collect::<String>();

error: aborting due to 5 previous errors
------------------------------------------

CAD97 and others added 9 commits May 23, 2022 09:20

Add a pointer to address cast kind

dff602f

A pointer to address cast are often special-cased. Introduce a dedicated cast kind to make them easy distinguishable.

BTreeSet->BTreeMap (fix copy/paste mistake in documentation)

e6b1003

Co-authored-by: lcnr <[email protected]>

Add regression test for rust-lang#71546

cf66d91

Rollup merge of rust-lang#97580 - JohnTitor:issue-71546, r=compiler-e…

a3d8b07

…rrors Add regression test for rust-lang#71546 Closes rust-lang#71546 r? `@compiler-errors`

Rollup merge of rust-lang#97582 - tmiasko:pointer-address-cast, r=oli…

c7dd5bc

…-obk Add a pointer to address cast kind A pointer to address cast are often special-cased. Introduce a dedicated cast kind to make them easy distinguishable.

rustbot added T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-libs Relevant to the library team, which will review and decide on the PR/issue. rollup A PR which is a rollup labels May 31, 2022

bors added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label May 31, 2022

bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels May 31, 2022

matthiaskrgr closed this May 31, 2022

matthiaskrgr deleted the rollup-0pr9wue branch July 30, 2022 10:32

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Rollup of 4 pull requests #97591

Rollup of 4 pull requests #97591

matthiaskrgr commented May 31, 2022

matthiaskrgr commented May 31, 2022

bors commented May 31, 2022

bors commented May 31, 2022

bors commented May 31, 2022

rust-log-analyzer commented May 31, 2022

Rollup of 4 pull requests #97591

Rollup of 4 pull requests #97591

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matthiaskrgr commented May 31, 2022

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