[DO NOT MERGE] [crater experiment] make unaligned_referenced deny-by-default #72644

RalfJung · 2020-05-27T06:27:33Z

@joshtriplett suggested we make a crater experiment to figure out how much code out there is creating bad references to packed fields.

rust-highfive · 2020-05-27T06:27:36Z

r? @ecstatic-morse

(rust_highfive has picked a reviewer for you, use r? to override)

RalfJung · 2020-05-27T06:55:31Z

@bors try

bors · 2020-05-27T06:55:49Z

⌛ Trying commit 8c413c3 with merge 1a399c10897767c36d147199696c96f193034e49...

rust-highfive · 2020-05-27T07:38:24Z

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##[section]Starting: Linux x86_64-gnu-llvm-8
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##[section]Finishing: Disable git automatic line ending conversion
##[section]Starting: Checkout rust-lang/rust@refs/pull/72644/merge to s
Task         : Get sources
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---
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Step 6/8 : ENV SCRIPT python2.7 ../x.py test --exclude src/tools/tidy &&            python2.7 ../x.py test src/test/mir-opt --pass=build                                   --target=armv5te-unknown-linux-gnueabi &&            python2.7 ../x.py test src/tools/tidy
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---
+    |
+ LL |     let _ = &p.b;
+    |             ^^^^
+    |
+    = note: `#[deny(unaligned_references)]` on by default
+    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+ error: reference to packed field is unaligned
+   --> $DIR/issue-53114-safety-checks.rs:29:17
+    |
+    |
+ LL |     let (_,) = (&p.b,);
+    |
+    |
+    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+ error: reference to packed field is unaligned
+   --> $DIR/issue-53114-safety-checks.rs:39:11
+    |
+    |
+ LL |     match &p.b  { _ => { } }
+    |
+    |
+    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+ error: reference to packed field is unaligned
+   --> $DIR/issue-53114-safety-checks.rs:45:12
+    |
+    |
+ LL |     match (&p.b,)  { (_,) => { } }
+    |
+    |
+    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
1 warning: borrow of packed field is unsafe and requires unsafe function or block (error E0133)
2   --> $DIR/issue-53114-safety-checks.rs:23:13
3    |


95    |
96    = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
97 
- error: aborting due to 7 previous errors; 4 warnings emitted
+ error: aborting due to 11 previous errors; 4 warnings emitted
100 For more information about this error, try `rustc --explain E0133`.
101 



The actual stderr differed from the expected stderr.
Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/binding/issue-53114-safety-checks/issue-53114-safety-checks.stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args binding/issue-53114-safety-checks.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/binding/issue-53114-safety-checks.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/binding/issue-53114-safety-checks" "-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/binding/issue-53114-safety-checks/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:23:13
   |
LL |     let _ = &p.b;  //~ WARN    E0133
   |
   = note: `#[deny(unaligned_references)]` on by default
   = note: `#[deny(unaligned_references)]` on by default
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:29:17
   |
   |
LL |     let (_,) = (&p.b,);  //~ WARN     E0133
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:39:11
   |
   |
LL |     match &p.b  { _ => { } } //~ WARN     E0133
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:45:12
   |
   |
LL |     match (&p.b,)  { (_,) => { } } //~ WARN     E0133
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
warning: borrow of packed field is unsafe and requires unsafe function or block (error E0133)
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:23:13
   |
   |
LL |     let _ = &p.b;  //~ WARN    E0133
   |
   |
   = note: `#[warn(safe_packed_borrows)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #46043 <***/issues/46043>
   = note: fields of packed structs might be misaligned: dereferencing a misaligned pointer or even just creating a misaligned reference is undefined behavior
error[E0133]: access to union field is unsafe and requires unsafe function or block
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:26:13
   |
   |
LL |     let _ = &u2.a; //~ ERROR  [E0133]
   |             ^^^^^ access to union field
   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior

warning: borrow of packed field is unsafe and requires unsafe function or block (error E0133)
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:29:17
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:29:17
   |
LL |     let (_,) = (&p.b,);  //~ WARN     E0133
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #46043 <***/issues/46043>
   = note: fields of packed structs might be misaligned: dereferencing a misaligned pointer or even just creating a misaligned reference is undefined behavior
error[E0133]: access to union field is unsafe and requires unsafe function or block
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:31:17
   |
   |
LL |     let (_,) = (u1.a,);  //~ ERROR   [E0133]
   |                 ^^^^ access to union field
   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior

error[E0133]: access to union field is unsafe and requires unsafe function or block
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:32:17
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:32:17
   |
LL |     let (_,) = (&u2.a,); //~ ERROR   [E0133]
   |                 ^^^^^ access to union field
   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior

warning: borrow of packed field is unsafe and requires unsafe function or block (error E0133)
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:39:11
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:39:11
   |
LL |     match &p.b  { _ => { } } //~ WARN     E0133
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #46043 <***/issues/46043>
   = note: fields of packed structs might be misaligned: dereferencing a misaligned pointer or even just creating a misaligned reference is undefined behavior
error[E0133]: access to union field is unsafe and requires unsafe function or block
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:41:11
   |
   |
LL |     match u1.a  { _ => { } } //~ ERROR   [E0133]
   |           ^^^^ access to union field
   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior

error[E0133]: access to union field is unsafe and requires unsafe function or block
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:42:11
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:42:11
   |
LL |     match &u2.a { _ => { } } //~ ERROR   [E0133]
   |           ^^^^^ access to union field
   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior

warning: borrow of packed field is unsafe and requires unsafe function or block (error E0133)
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:45:12
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:45:12
   |
LL |     match (&p.b,)  { (_,) => { } } //~ WARN     E0133
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #46043 <***/issues/46043>
   = note: fields of packed structs might be misaligned: dereferencing a misaligned pointer or even just creating a misaligned reference is undefined behavior
error[E0133]: access to union field is unsafe and requires unsafe function or block
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:47:12
   |
   |
LL |     match (u1.a,)  { (_,) => { } } //~ ERROR   [E0133]
   |            ^^^^ access to union field
   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior

error[E0133]: access to union field is unsafe and requires unsafe function or block
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:48:12
  --> /checkout/src/test/ui/binding/issue-53114-safety-checks.rs:48:12
   |
LL |     match (&u2.a,) { (_,) => { } } //~ ERROR   [E0133]
   |            ^^^^^ access to union field
   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior


error: aborting due to 11 previous errors; 4 warnings emitted
For more information about this error, try `rustc --explain E0133`.

------------------------------------------



---- [ui] ui/issues/issue-27060-rpass.rs stdout ----

error: test compilation failed although it shouldn't!
status: exit code: 1
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/issues/issue-27060-rpass.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/issues/issue-27060-rpass/a" "-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/issues/issue-27060-rpass/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/issues/issue-27060-rpass.rs:16:17
   |
LL |         let _ = &good.data; // ok
   |
   = note: `#[deny(unaligned_references)]` on by default
   = note: `#[deny(unaligned_references)]` on by default
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/issues/issue-27060-rpass.rs:17:17
   |
   |
LL |         let _ = &good.data2[0]; // ok
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/issues/issue-27060-rpass.rs:20:13
   |
   |
LL |     let _ = &good.data;
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/issues/issue-27060-rpass.rs:21:13
   |
   |
LL |     let _ = &good.data2[0];
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: aborting due to 4 previous errors


------------------------------------------
---

+ error: reference to packed field is unaligned
+   --> $DIR/issue-27060.rs:17:17
+    |
+ LL |         let _ = &good.data; // ok
+    |
+    = note: `#[deny(unaligned_references)]` on by default
+    = note: `#[deny(unaligned_references)]` on by default
+    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+ error: reference to packed field is unaligned
+   --> $DIR/issue-27060.rs:18:17
+    |
+    |
+ LL |         let _ = &good.data2[0]; // ok
+    |
+    |
+    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+ error: reference to packed field is unaligned
+   --> $DIR/issue-27060.rs:21:13
+    |
+    |
+ LL |     let _ = &good.data;
+    |
+    |
+    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+ error: reference to packed field is unaligned
+   --> $DIR/issue-27060.rs:23:13
+    |
+    |
+ LL |     let _ = &good.data2[0];
+    |
+    |
+    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
1 error: borrow of packed field is unsafe and requires unsafe function or block (error E0133)
2   --> $DIR/issue-27060.rs:21:13
3    |


23    = note: for more information, see issue #46043 <***/issues/46043>
24    = note: fields of packed structs might be misaligned: dereferencing a misaligned pointer or even just creating a misaligned reference is undefined behavior
- error: aborting due to 2 previous errors
+ error: aborting due to 6 previous errors
27 
28 
28 


The actual stderr differed from the expected stderr.
Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/issues/issue-27060/issue-27060.stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args issues/issue-27060.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/issues/issue-27060.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/issues/issue-27060" "-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/issues/issue-27060/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/issues/issue-27060.rs:17:17
   |
LL |         let _ = &good.data; // ok
   |
   = note: `#[deny(unaligned_references)]` on by default
   = note: `#[deny(unaligned_references)]` on by default
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/issues/issue-27060.rs:18:17
   |
   |
LL |         let _ = &good.data2[0]; // ok
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/issues/issue-27060.rs:21:13
   |
   |
LL |     let _ = &good.data; //~ ERROR borrow of packed field is unsafe
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/issues/issue-27060.rs:23:13
   |
   |
LL |     let _ = &good.data2[0]; //~ ERROR borrow of packed field is unsafe
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: borrow of packed field is unsafe and requires unsafe function or block (error E0133)
  --> /checkout/src/test/ui/issues/issue-27060.rs:21:13
   |
   |
LL |     let _ = &good.data; //~ ERROR borrow of packed field is unsafe
   |
note: the lint level is defined here
  --> /checkout/src/test/ui/issues/issue-27060.rs:8:8
   |
   |
LL | #[deny(safe_packed_borrows)]
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #46043 <***/issues/46043>
   = note: fields of packed structs might be misaligned: dereferencing a misaligned pointer or even just creating a misaligned reference is undefined behavior
error: borrow of packed field is unsafe and requires unsafe function or block (error E0133)
  --> /checkout/src/test/ui/issues/issue-27060.rs:23:13
   |
   |
LL |     let _ = &good.data2[0]; //~ ERROR borrow of packed field is unsafe
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #46043 <***/issues/46043>
   = note: fields of packed structs might be misaligned: dereferencing a misaligned pointer or even just creating a misaligned reference is undefined behavior
error: aborting due to 6 previous errors


------------------------------------------
------------------------------------------


---- [ui] ui/packed/packed-struct-borrow-element.rs stdout ----

error: test compilation failed although it shouldn't!
status: exit code: 1
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/packed/packed-struct-borrow-element.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/packed/packed-struct-borrow-element/a" "-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/packed/packed-struct-borrow-element/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/packed/packed-struct-borrow-element.rs:25:24
   |
LL |     let brw = unsafe { &foo.baz };
   |
   = note: `#[deny(unaligned_references)]` on by default
   = note: `#[deny(unaligned_references)]` on by default
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/packed/packed-struct-borrow-element.rs:29:24
   |
   |
LL |     let brw = unsafe { &foo.baz };
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: reference to packed field is unaligned
  --> /checkout/src/test/ui/packed/packed-struct-borrow-element.rs:33:24
   |
   |
LL |     let brw = unsafe { &foo.baz };
   |
   |
   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
error: aborting due to 3 previous errors


------------------------------------------
---
thread 'main' panicked at 'Some tests failed', src/tools/compiletest/src/main.rs:348:22
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


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" "--mode" "ui" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-8/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" "8.0.0" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"


failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test --exclude src/tools/tidy
Build completed unsuccessfully in 1:05:45
Build completed unsuccessfully in 1:05:45
== clock drift check ==
  local time: Wed May 27 07:38:06 UTC 2020
  network time: Wed, 27 May 2020 07:38:06 GMT
== end clock drift check ==

##[error]Bash exited with code '1'.
##[section]Finishing: Run build
##[section]Starting: Checkout rust-lang/rust@refs/pull/72644/merge to s
Task         : Get sources
Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
Version      : 1.0.0
Author       : Microsoft
Author       : Microsoft
Help         : [More Information](https://go.microsoft.com/fwlink/?LinkId=798199)
==============================================================================
Cleaning any cached credential from repository: rust-lang/rust (GitHub)
##[section]Finishing: Checkout rust-lang/rust@refs/pull/72644/merge to s
Cleaning up task key
Start cleaning up orphan processes.
Terminate orphan process: pid (3967) (python)
##[section]Finishing: Finalize Job

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @rust-lang/infra. (Feature Requests)

bors · 2020-05-27T09:58:29Z

☀️ Try build successful - checks-azure
Build commit: 1a399c10897767c36d147199696c96f193034e49 (1a399c10897767c36d147199696c96f193034e49)

RalfJung · 2020-05-27T09:59:21Z

@craterbot check

craterbot · 2020-05-27T09:59:24Z

👌 Experiment pr-72644 created and queued.
🤖 Automatically detected try build 1a399c10897767c36d147199696c96f193034e49
🔍 You can check out the queue and this experiment's details.

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

bluss · 2020-05-27T12:50:15Z

Lint from #72270

Does this lint also catch method calls, where &self is the unaligned reference?

RalfJung · 2020-05-27T13:06:50Z

It works on the MIR level, so it definitely should. Do you have a testcase?

bluss · 2020-05-27T13:54:14Z

I haven't tried, so it probably works. Based on the PR, the test can be this?

#![deny(unaligned_references)]

#[repr(packed)]
pub struct Good {
    data: &'static u32,
    data2: [&'static u32; 2],
    data3: u64,
    aligned: [u8; 32],
}

fn main() {
    unsafe {
        let good = Good { data: &0, data2: [&0, &0], data3: 0, aligned: [0; 32] };

        let _ = good.data2.first(); //~ ERROR reference to packed field
        let _ = good.data3.clone(); //~ ERROR reference to packed field
        let _ = &good.data; //~ ERROR reference to packed field
        let _ = &good.data as *const _; //~ ERROR reference to packed field
        let _: *const _ = &good.data; //~ ERROR reference to packed field
        let _ = &good.data2[0]; //~ ERROR reference to packed field
        let _ = &*good.data; // ok, behind a pointer
        let _ = &good.aligned; // ok, has align 1
        let _ = &good.aligned[2]; // ok, has align 1
    }
}

I don't know if you are using references to have it be portable - I used u64 to ensure without inserting & that it calls a &self method like Clone.

d'oh I suppose it's better to just define the required methods in the test case.

RalfJung · 2020-05-27T18:17:43Z

I copied that Good struct from another test. No idea why that one uses references...

craterbot · 2020-05-30T20:39:56Z

🚧 Experiment pr-72644 is now running

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

retep998 · 2020-05-31T00:43:48Z

I'd like to point out that the results of this crater run will very likely significantly underestimate the rate of violations as winapi has entire modules full of packed structs, and a lot of windows specific code is liable to accidentally make references to fields from such structs.

craterbot · 2020-06-02T00:32:49Z

🎉 Experiment pr-72644 is completed!
📊 80 regressed and 2 fixed (106133 total)
📰 Open the full report.

⚠️ If you notice any spurious failure please add them to the blacklist!
ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

RalfJung · 2020-06-02T07:21:50Z

Discussion of the results happens at #27060 (comment).

[crater experiment] make unaligned_referenced deny-by-default

8c413c3

rust-highfive assigned ecstatic-morse May 27, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label May 27, 2020

craterbot added S-waiting-on-crater Status: Waiting on a crater run to be completed. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels May 27, 2020

RalfJung mentioned this pull request May 28, 2020

repr(packed) allows invalid unaligned loads #27060

Closed

craterbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-crater Status: Waiting on a crater run to be completed. labels Jun 2, 2020

RalfJung closed this Jun 2, 2020

RalfJung deleted the crater-unaligned-refs branch June 2, 2020 07:21

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