compiler: Include span of too huge array with `-Cdebuginfo=2` #146025

Enselic · 2025-08-30T09:15:53Z

We have a few ui tests to ensure we emit an error if we encounter too big arrays. Before this fix, compiling the tests with -Cdebuginfo=2 would not include the spans of the instantiation sites, because the error is then emitted from a different code path that does not include the span.

Propagate the span to the error also in the debuginfo case, so the tests passes regardless of debuginfo level.

r? @wesleywiser since this is a natural continuation of #145967 that you approved (thanks!).

cc #61117 since this takes is one step closer to increasing rust.debuginfo-level-tests to 2 in the x86_64-gnu-debug CI job.

Test failure output without the fix

Here is what the test failures look like if you run the tests without the fix. (Click to expand.)

$ ./x test --set rust.debuginfo-level-tests=2 tests/ui/limits/huge-array-simple-64.rs tests/ui/limits/huge-array.rs tests/ui/limits/issue-15919-64.rs
Building bootstrap
    Finished `dev` profile [unoptimized] target(s) in 0.16s
/home/martin/src/rust/build/x86_64-unknown-linux-gnu/ci-llvm/bin/llvm-strip does not exist; skipping copy
Building stage1 compiler artifacts (stage0 -> stage1, x86_64-unknown-linux-gnu)
    Finished `release` profile [optimized + debuginfo] target(s) in 0.40s
Creating a sysroot for stage1 compiler (use `rustup toolchain link 'name' build/host/stage1`)
Building stage1 lld-wrapper (stage0 -> stage1, x86_64-unknown-linux-gnu)
    Finished `release` profile [optimized + debuginfo] target(s) in 0.08s
Building stage1 library artifacts (stage1 -> stage1, x86_64-unknown-linux-gnu)
   Compiling addr2line v0.25.0
   Compiling std v0.0.0 (/home/martin/src/rust/library/std)
   Compiling rustc-std-workspace-std v1.99.0 (/home/martin/src/rust/library/rustc-std-workspace-std)
   Compiling unicode-width v0.2.1
   Compiling rustc-literal-escaper v0.0.5
   Compiling proc_macro v0.0.0 (/home/martin/src/rust/library/proc_macro)
   Compiling getopts v0.2.23
   Compiling test v0.0.0 (/home/martin/src/rust/library/test)
   Compiling sysroot v0.0.0 (/home/martin/src/rust/library/sysroot)
    Finished `release` profile [optimized + debuginfo] target(s) in 14.43s
Building stage1 compiletest (stage0 -> stage1, x86_64-unknown-linux-gnu)
    Finished `release` profile [optimized + debuginfo] target(s) in 0.14s
Testing stage2 compiletest suite=ui mode=ui (stage1 -> stage2, x86_64-unknown-linux-gnu)

running 6 tests

[ui] tests/ui/limits/huge-array.rs#full-debuginfo ... F

[ui] tests/ui/limits/issue-15919-64.rs#full-debuginfo ... F

[ui] tests/ui/limits/huge-array-simple-64.rs#full-debuginfo ... F
...

failures:

---- [ui] tests/ui/limits/huge-array.rs#full-debuginfo stdout ----
Saved the actual stderr to `/home/martin/src/rust/build/x86_64-unknown-linux-gnu/test/ui/limits/huge-array.full-debuginfo/huge-array.full-debuginfo.stderr`
diff of stderr:

1       error: values of the type `[[u8; 1518599999]; 1518600000]` are too big for the target architecture
-         --> $DIR/huge-array.rs:9:9
-          |
-       LL |     let s: [T; 1518600000] = [t; 1518600000];
-          |         ^
6
7       error: aborting due to 1 previous error
8


The actual stderr differed from the expected stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args limits/huge-array.rs`

error in revision `full-debuginfo`: 1 errors occurred comparing output.
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1/bin/rustc" "/home/martin/src/rust/tests/ui/limits/huge-array.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/home/martin/.cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/home/martin/src/rust/vendor" "--sysroot" "/home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1" "--target=x86_64-unknown-linux-gnu" "--cfg" "full_debuginfo" "--check-cfg" "cfg(test,FALSE,no_debuginfo,full_debuginfo)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/home/martin/src/rust/build/x86_64-unknown-linux-gnu/test/ui/limits/huge-array.full-debuginfo" "-A" "unused" "-A" "internal_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Lnative=/home/martin/src/rust/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-Cdebuginfo=2"
stdout: none
--- stderr -------------------------------
error: values of the type `[[u8; 1518599999]; 1518600000]` are too big for the target architecture

error: aborting due to 1 previous error
------------------------------------------

---- [ui] tests/ui/limits/huge-array.rs#full-debuginfo stdout end ----
---- [ui] tests/ui/limits/issue-15919-64.rs#full-debuginfo stdout ----
Saved the actual stderr to `/home/martin/src/rust/build/x86_64-unknown-linux-gnu/test/ui/limits/issue-15919-64.full-debuginfo/issue-15919-64.full-debuginfo.stderr`
diff of stderr:

1       error: values of the type `[usize; usize::MAX]` are too big for the target architecture
-         --> $DIR/issue-15919-64.rs:10:9
-          |
-       LL |     let x = [0usize; 0xffff_ffff_ffff_ffff];
-          |         ^
6
7       error: aborting due to 1 previous error
8


The actual stderr differed from the expected stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args limits/issue-15919-64.rs`

error in revision `full-debuginfo`: 1 errors occurred comparing output.
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1/bin/rustc" "/home/martin/src/rust/tests/ui/limits/issue-15919-64.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/home/martin/.cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/home/martin/src/rust/vendor" "--sysroot" "/home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1" "--target=x86_64-unknown-linux-gnu" "--cfg" "full_debuginfo" "--check-cfg" "cfg(test,FALSE,no_debuginfo,full_debuginfo)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/home/martin/src/rust/build/x86_64-unknown-linux-gnu/test/ui/limits/issue-15919-64.full-debuginfo" "-A" "unused" "-A" "internal_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Lnative=/home/martin/src/rust/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-Cdebuginfo=2"
stdout: none
--- stderr -------------------------------
error: values of the type `[usize; usize::MAX]` are too big for the target architecture

error: aborting due to 1 previous error
------------------------------------------

---- [ui] tests/ui/limits/issue-15919-64.rs#full-debuginfo stdout end ----
---- [ui] tests/ui/limits/huge-array-simple-64.rs#full-debuginfo stdout ----
Saved the actual stderr to `/home/martin/src/rust/build/x86_64-unknown-linux-gnu/test/ui/limits/huge-array-simple-64.full-debuginfo/huge-array-simple-64.full-debuginfo.stderr`
diff of stderr:

1       error: values of the type `[u8; 2305843011361177600]` are too big for the target architecture
-         --> $DIR/huge-array-simple-64.rs:12:9
-          |
-       LL |     let _fat: [u8; (1<<61)+(1<<31)] =
-          |         ^^^^
6
7       error: aborting due to 1 previous error
8


The actual stderr differed from the expected stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args limits/huge-array-simple-64.rs`

error in revision `full-debuginfo`: 1 errors occurred comparing output.
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1/bin/rustc" "/home/martin/src/rust/tests/ui/limits/huge-array-simple-64.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/home/martin/.cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/home/martin/src/rust/vendor" "--sysroot" "/home/martin/src/rust/build/x86_64-unknown-linux-gnu/stage1" "--target=x86_64-unknown-linux-gnu" "--cfg" "full_debuginfo" "--check-cfg" "cfg(test,FALSE,no_debuginfo,full_debuginfo)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/home/martin/src/rust/build/x86_64-unknown-linux-gnu/test/ui/limits/huge-array-simple-64.full-debuginfo" "-A" "unused" "-A" "internal_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Lnative=/home/martin/src/rust/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-Cdebuginfo=2"
stdout: none
--- stderr -------------------------------
error: values of the type `[u8; 2305843011361177600]` are too big for the target architecture

error: aborting due to 1 previous error
------------------------------------------

---- [ui] tests/ui/limits/huge-array-simple-64.rs#full-debuginfo stdout end ----

failures:
    [ui] tests/ui/limits/huge-array.rs#full-debuginfo
    [ui] tests/ui/limits/issue-15919-64.rs#full-debuginfo
    [ui] tests/ui/limits/huge-array-simple-64.rs#full-debuginfo

test result: FAILED. 3 passed; 3 failed; 0 ignored; 0 measured; 19720 filtered out; finished in 117.18ms

Some tests failed in compiletest suite=ui mode=ui host=x86_64-unknown-linux-gnu target=x86_64-unknown-linux-gnu
Build completed unsuccessfully in 0:00:17

As can be seen, the span info is missing with debuginfo=2 without the fix.

We have a few ui tests to ensure we emit an error if we encounter too big arrays. Before this fix, compiling the tests with `-Cdebuginfo=2` would not include the spans of the instantiation sites, because the error is then emitted from a different code path that does not include the span. Propagate the span to the error also in the debuginfo case, so the tests passes regardless of debuginfo level.

rustbot assigned wesleywiser Aug 30, 2025

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compiler: Include span of too huge array with `-Cdebuginfo=2` #146025

compiler: Include span of too huge array with `-Cdebuginfo=2` #146025

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Enselic commented Aug 30, 2025 •

edited

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compiler: Include span of too huge array with -Cdebuginfo=2 #146025

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Test failure output without the fix

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compiler: Include span of too huge array with `-Cdebuginfo=2` #146025

compiler: Include span of too huge array with `-Cdebuginfo=2` #146025

Enselic commented Aug 30, 2025 •

edited

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