diagnostics: hide expansion of builtin-like macros

[mejrs]

As of late I've gotten more and more annoyed by notes like note: this error originates in the macro $crate::__export::format_args.

This PR hides that message if it comes from an expansion of a macro that uses features like fmt_internals. If its expansion is an implementation detail we shouldn't be mentioning it. This covers macros like vec!, format! and so on, but not the more mundane ones like assert_eq! and todo!!

[rustbot]

r? @nnethercote

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[nnethercote]

Might be worth pulling everything after the first || out into a separate variable.

Also, I don't really understand how this works, i.e. how allow_internal_unstable is involved. A brief comment explaining it would be useful.

[nnethercote]

Generally looks good, I will r+ once the tests all pass the the suggestion above is addressed. Thanks.

@rustbot author

[rustbot]

Reminder, once the PR becomes ready for a review, use @rustbot ready.

[bjorn3]

Does -Zmacro-backtrace still work for builtin-like macros with this PR?

[petrochenkov]

I just recently rejected this change in #138379.

[rust-log-analyzer]

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

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

tests/fail/function_calls/exported_symbol_bad_unwind2.rs (revision `definition`) ... ok
tests/fail/function_calls/exported_symbol_bad_unwind2.rs (revision `both`) ... ok

FAILED TEST: tests/fail/erroneous_const2.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-WnPdKX" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/miri" "--error-format=json" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/fail" "tests/fail/erroneous_const2.rs" "--edition" "2021"

error: actual output differed from expected
Execute `./miri test --bless` to update `tests/fail/erroneous_const2.stderr` to the actual output
--- tests/fail/erroneous_const2.stderr
+++ <stderr output>
---
   |
LL |     println!("{}", FOO);
   |                    ^^^
   |
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

note: erroneous constant encountered
  --> tests/fail/erroneous_const2.rs:8:20
   |
LL |     println!("{}", FOO);
---
   |
LL |     println!("{}", FOO);
   |                    ^^^
   |
   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

note: erroneous constant encountered
  --> tests/fail/erroneous_const2.rs:8:20
   |
LL |     println!("{}", FOO);
---



FAILED TEST: tests/fail/dangling_pointers/out_of_bounds_read.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-WnPdKX" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/miri" "--error-format=json" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/fail/dangling_pointers" "tests/fail/dangling_pointers/out_of_bounds_read.rs" "--edition" "2021"

error: actual output differed from expected
Execute `./miri test --bless` to update `tests/fail/dangling_pointers/out_of_bounds_read.stderr` to the actual output
--- tests/fail/dangling_pointers/out_of_bounds_read.stderr
+++ <stderr output>
 error: Undefined Behavior: memory access failed: attempting to access 2 bytes, but got ALLOC+0x5 which is at or beyond the end of the allocation of size 4 bytes
   --> tests/fail/dangling_pointers/out_of_bounds_read.rs:LL:CC
... 11 lines skipped ...
    = note: BACKTRACE (of the first span):
    = note: inside `main` at tests/fail/dangling_pointers/out_of_bounds_read.rs:LL:CC
-   = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error
 

Full unnormalized output:
error: Undefined Behavior: memory access failed: attempting to access 2 bytes, but got alloc398+0x5 which is at or beyond the end of the allocation of size 4 bytes
##[error]  --> tests/fail/dangling_pointers/out_of_bounds_read.rs:4:22
   |
LL |     let x = unsafe { *v.as_ptr().wrapping_byte_add(5) };
   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: attempting to access 2 bytes, but got alloc398+0x5 which is at or beyond the end of the allocation of size 4 bytes
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
help: alloc398 was allocated here:
  --> tests/fail/dangling_pointers/out_of_bounds_read.rs:2:23
   |
LL |     let v: Vec<u16> = vec![1, 2];
   |                       ^^^^^^^^^^
   = note: BACKTRACE (of the first span):
   = note: inside `main` at tests/fail/dangling_pointers/out_of_bounds_read.rs:4:22: 4:54

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

error: aborting due to 1 previous error



full stderr:
error: Undefined Behavior: memory access failed: attempting to access 2 bytes, but got alloc398+0x5 which is at or beyond the end of the allocation of size 4 bytes
##[error]  --> tests/fail/dangling_pointers/out_of_bounds_read.rs:4:22
   |
LL |     let x = unsafe { *v.as_ptr().wrapping_byte_add(5) };
   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: attempting to access 2 bytes, but got alloc398+0x5 which is at or beyond the end of the allocation of size 4 bytes
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
help: alloc398 was allocated here:
  --> tests/fail/dangling_pointers/out_of_bounds_read.rs:2:23
   |
LL |     let v: Vec<u16> = vec![1, 2];
   |                       ^^^^^^^^^^
   = note: BACKTRACE (of the first span):
   = note: inside `main` at tests/fail/dangling_pointers/out_of_bounds_read.rs:4:22: 4:54

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
---



FAILED TEST: tests/fail/dangling_pointers/out_of_bounds_write.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-WnPdKX" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/miri" "--error-format=json" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/fail/dangling_pointers" "tests/fail/dangling_pointers/out_of_bounds_write.rs" "--edition" "2021"

error: actual output differed from expected
Execute `./miri test --bless` to update `tests/fail/dangling_pointers/out_of_bounds_write.stderr` to the actual output
--- tests/fail/dangling_pointers/out_of_bounds_write.stderr
+++ <stderr output>
 error: Undefined Behavior: memory access failed: attempting to access 2 bytes, but got ALLOC+0x5 which is at or beyond the end of the allocation of size 4 bytes
   --> tests/fail/dangling_pointers/out_of_bounds_write.rs:LL:CC
... 11 lines skipped ...
    = note: BACKTRACE (of the first span):
    = note: inside `main` at tests/fail/dangling_pointers/out_of_bounds_write.rs:LL:CC
-   = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error
 

Full unnormalized output:
error: Undefined Behavior: memory access failed: attempting to access 2 bytes, but got alloc394+0x5 which is at or beyond the end of the allocation of size 4 bytes
##[error]  --> tests/fail/dangling_pointers/out_of_bounds_write.rs:4:14
   |
LL |     unsafe { *v.as_mut_ptr().wrapping_byte_add(5) = 0 };
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: attempting to access 2 bytes, but got alloc394+0x5 which is at or beyond the end of the allocation of size 4 bytes
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
help: alloc394 was allocated here:
  --> tests/fail/dangling_pointers/out_of_bounds_write.rs:2:27
   |
LL |     let mut v: Vec<u16> = vec![1, 2];
   |                           ^^^^^^^^^^
   = note: BACKTRACE (of the first span):
   = note: inside `main` at tests/fail/dangling_pointers/out_of_bounds_write.rs:4:14: 4:54

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

error: aborting due to 1 previous error



full stderr:
error: Undefined Behavior: memory access failed: attempting to access 2 bytes, but got alloc394+0x5 which is at or beyond the end of the allocation of size 4 bytes
##[error]  --> tests/fail/dangling_pointers/out_of_bounds_write.rs:4:14
   |
LL |     unsafe { *v.as_mut_ptr().wrapping_byte_add(5) = 0 };
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: attempting to access 2 bytes, but got alloc394+0x5 which is at or beyond the end of the allocation of size 4 bytes
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
help: alloc394 was allocated here:
  --> tests/fail/dangling_pointers/out_of_bounds_write.rs:2:27
   |
LL |     let mut v: Vec<u16> = vec![1, 2];
   |                           ^^^^^^^^^^
   = note: BACKTRACE (of the first span):
   = note: inside `main` at tests/fail/dangling_pointers/out_of_bounds_write.rs:4:14: 4:54

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
---



FAILED TEST: tests/fail/intrinsics/simd-scatter.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-WnPdKX" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/miri" "--error-format=json" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/fail/intrinsics" "tests/fail/intrinsics/simd-scatter.rs" "--edition" "2021"

error: actual output differed from expected
Execute `./miri test --bless` to update `tests/fail/intrinsics/simd-scatter.stderr` to the actual output
--- tests/fail/intrinsics/simd-scatter.stderr
+++ <stderr output>
 error: Undefined Behavior: memory access failed: attempting to access 1 byte, but got ALLOC+0x9 which is at or beyond the end of the allocation of size 9 bytes
   --> tests/fail/intrinsics/simd-scatter.rs:LL:CC
... 16 lines skipped ...
    = note: BACKTRACE (of the first span):
    = note: inside `main` at tests/fail/intrinsics/simd-scatter.rs:LL:CC
-   = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error
 

Full unnormalized output:
error: Undefined Behavior: memory access failed: attempting to access 1 byte, but got alloc394+0x9 which is at or beyond the end of the allocation of size 9 bytes
##[error]  --> tests/fail/intrinsics/simd-scatter.rs:8:9
   |
LL | /         Simd::from_array([-27, 82, -41, 124]).scatter_select_unchecked(
LL | |
LL | |             &mut vec,
LL | |             Mask::splat(true),
LL | |             idxs,
LL | |         );
   | |_________^ memory access failed: attempting to access 1 byte, but got alloc394+0x9 which is at or beyond the end of the allocation of size 9 bytes
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
help: alloc394 was allocated here:
  --> tests/fail/intrinsics/simd-scatter.rs:6:32
   |
LL |         let mut vec: Vec<i8> = vec![10, 11, 12, 13, 14, 15, 16, 17, 18];
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: BACKTRACE (of the first span):
   = note: inside `main` at tests/fail/intrinsics/simd-scatter.rs:8:9: 13:10

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

error: aborting due to 1 previous error



full stderr:
error: Undefined Behavior: memory access failed: attempting to access 1 byte, but got alloc394+0x9 which is at or beyond the end of the allocation of size 9 bytes
##[error]  --> tests/fail/intrinsics/simd-scatter.rs:8:9
   |
LL | /         Simd::from_array([-27, 82, -41, 124]).scatter_select_unchecked(
LL | |
LL | |             &mut vec,
LL | |             Mask::splat(true),
LL | |             idxs,
LL | |         );
   | |_________^ memory access failed: attempting to access 1 byte, but got alloc394+0x9 which is at or beyond the end of the allocation of size 9 bytes
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
help: alloc394 was allocated here:
  --> tests/fail/intrinsics/simd-scatter.rs:6:32
   |
LL |         let mut vec: Vec<i8> = vec![10, 11, 12, 13, 14, 15, 16, 17, 18];
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: BACKTRACE (of the first span):
   = note: inside `main` at tests/fail/intrinsics/simd-scatter.rs:8:9: 13:10

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
---



FAILED TEST: tests/fail/tree_borrows/protector-write-lazy.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-WnPdKX" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/miri" "--error-format=json" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/fail/tree_borrows" "tests/fail/tree_borrows/protector-write-lazy.rs" "-Zmiri-tree-borrows" "--edition" "2021"

error: actual output differed from expected
Execute `./miri test --bless` to update `tests/fail/tree_borrows/protector-write-lazy.stderr` to the actual output
--- tests/fail/tree_borrows/protector-write-lazy.stderr
+++ <stderr output>
 error: Undefined Behavior: reborrow through <TAG> at ALLOC[0x0] is forbidden
   --> tests/fail/tree_borrows/protector-write-lazy.rs:LL:CC
... 17 lines skipped ...
    = note: BACKTRACE (of the first span):
    = note: inside `main` at tests/fail/tree_borrows/protector-write-lazy.rs:LL:CC
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
 error: aborting due to 1 previous error
 

Full unnormalized output:
error: Undefined Behavior: reborrow through <826> at alloc400[0x0] is forbidden
##[error]  --> tests/fail/tree_borrows/protector-write-lazy.rs:34:45
   |
LL |     unsafe { println!("Value of funky: {}", *funky_ptr_lazy_on_fst_elem) }
   |                                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ reborrow through <826> at alloc400[0x0] is forbidden
   |
   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
   = help: the accessed tag <826> has state Disabled which forbids this reborrow (acting as a child read access)
help: the accessed tag <826> was created here, in the initial state Reserved
  --> tests/fail/tree_borrows/protector-write-lazy.rs:17:18
   |
LL |         unsafe { (&mut *(ptr_to_vec.wrapping_add(1))) as *mut i32 }.wrapping_sub(1);
   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: the accessed tag <826> later transitioned to Disabled due to a protector release (acting as a foreign write access) on every location previously accessed by this tag
  --> tests/fail/tree_borrows/protector-write-lazy.rs:22:2
   |
LL | }
   |  ^
   = help: this transition corresponds to a loss of read and write permissions
---



full stderr:
error: Undefined Behavior: reborrow through <826> at alloc400[0x0] is forbidden
##[error]  --> tests/fail/tree_borrows/protector-write-lazy.rs:34:45
   |
LL |     unsafe { println!("Value of funky: {}", *funky_ptr_lazy_on_fst_elem) }
   |                                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ reborrow through <826> at alloc400[0x0] is forbidden
   |
   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
   = help: the accessed tag <826> has state Disabled which forbids this reborrow (acting as a child read access)
help: the accessed tag <826> was created here, in the initial state Reserved
  --> tests/fail/tree_borrows/protector-write-lazy.rs:17:18
   |
LL |         unsafe { (&mut *(ptr_to_vec.wrapping_add(1))) as *mut i32 }.wrapping_sub(1);
   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: the accessed tag <826> later transitioned to Disabled due to a protector release (acting as a foreign write access) on every location previously accessed by this tag
  --> tests/fail/tree_borrows/protector-write-lazy.rs:22:2
   |
LL | }
   |  ^
   = help: this transition corresponds to a loss of read and write permissions
---

Location:
   /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/ui_test-0.29.2/src/lib.rs:369

Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.
error: test failed, to rerun pass `--test ui`

Caused by:
  process didn't exit successfully: `/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/x86_64-unknown-linux-gnu/release/deps/ui-5a4f22761d8182b7` (exit status: 1)
Command has failed. Rerun with -v to see more details.
Build completed unsuccessfully in 0:04:42
  local time: Wed May 21 13:00:45 UTC 2025
  network time: Wed, 21 May 2025 13:00:45 GMT
##[error]Process completed with exit code 1.
Post job cleanup.