Add `_value` API for number literals in proc-macro by GuillaumeGomez · Pull Request #154608 · rust-lang/rust

GuillaumeGomez · 2026-03-30T21:28:58Z

This PR adds the *_value for numbers (integers and floats). However, f16 and f128 are voluntarily left out as they're still unstable. Adding support for them is just a matter of uncommenting two lines, so should be fine.

Setting same reviewer as last time.

r? @Urgau

GuillaumeGomez · 2026-03-31T09:54:15Z

My favourite kind of failure: works locally but not in CI. T_T

Updated the value in the tests to see which one exactly is failing.

GuillaumeGomez · 2026-03-31T13:14:56Z

Bug comes from an issue with GCC proc-macro ABI. Ignoring this test on GCC backend for now.

GuillaumeGomez · 2026-03-31T15:53:01Z

CI fixed. :)

Urgau · 2026-03-31T21:50:31Z

A libs (or maybe even libs-api) reviewer seems more appropriate to review this PR.

r? Amanieu (since you reviewed #136355)

Urgau · 2026-03-31T21:59:37Z

I missed it already has an accepted ACP. The PR can be reviewed by libs reviewer.

r? libs

Mark-Simulacrum · 2026-04-04T15:58:06Z

+    Hexadecimal = 16,
+}
+
+fn parse_number(value: &str) -> (String, Base) {


Is this exactly in sync with what the rustc parser permits?

I guess that would be a mix of https://doc.rust-lang.org/nightly/reference/tokens.html#grammar-INTEGER_LITERAL and whatever we then tokenize from it?

Perhaps this should go over the bridge and ask rustc to parse the string for us?

There is no code in rustc currently which would allow this conversion without including a lot of other things. My code is a simplified version of integer_lit (from rustc_ast/src/util/literal.rs) which parses both the number, its base and its suffix (which we already have) and returns a LitKind, which is also unnecessary here since we already know the end type.

I think my question is not about specific code in rustc but rather whether the implementation here parses exactly the same literals that rustc would from the given token(s). Is that the case? Essentially, can we document these functions as being bug-for-bug compatible with what rustc would do, or do we need a separate grammar for this?

At this point, the compiler already ran on the literal so all errors have been checked already. The remaining potential errors mostly come from trying to convert a int/float not fitting the expected output.

GuillaumeGomez · 2026-04-10T14:38:15Z

Added the method for f16, renamed the function only_digits into strip_underscores and improve the code of parse_number a bit to remove allocations.

GuillaumeGomez · 2026-05-12T00:00:57Z

Forgot to change the status.

@rustbot ready

cc @Mark-Simulacrum

Mark-Simulacrum · 2026-05-31T14:46:52Z

Can you reply to my comment here? #154608 (comment)

@rustbot author

GuillaumeGomez · 2026-06-02T20:13:17Z

Forgot to do so. Answered it.

@rustbot ready

…=<try> Add `_value` API for number literals in proc-macro try-job: x86_64-mingw-1

rust-bors · 2026-06-07T00:13:49Z

💔 Test for 1d1d12a failed: CI. Failed job:

try - x86_64-mingw-1 (web logs, enhanced plaintext logs)

GuillaumeGomez · 2026-06-07T19:22:12Z

@bors try jobs=x86_64-mingw-1

…=<try> Add `_value` API for number literals in proc-macro try-job: x86_64-mingw-1

rust-bors · 2026-06-07T21:21:44Z

💔 Test for f7e180c failed: CI. Failed job:

try - x86_64-mingw-1 (web logs, enhanced plaintext logs)

rust-log-analyzer · 2026-06-07T21:21:48Z

The job x86_64-mingw-1 failed! Check out the build log: (web) (plain enhanced) (plain)

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

failures:

---- [ui] tests\ui\proc-macro\test.rs stdout ----

error: auxiliary build of D:\a\rust\rust\tests\ui\proc-macro\auxiliary\api/proc_macro_api_tests.rs failed to compile: 
status: exit code: 1
command: PATH="D:\a\rust\rust\build\x86_64-pc-windows-gnu\stage2\bin;D:\a\rust\rust\build\x86_64-pc-windows-gnu\bootstrap-tools\x86_64-pc-windows-gnu\release\deps;D:\a\rust\rust\ninja;D:\a\rust\rust\mingw64\bin;C:\msys64\usr\bin;D:\a\rust\rust\sccache;C:\Program Files\MongoDB\Server\7.0\bin;C:\vcpkg;C:\tools\zstd;C:\hostedtoolcache\windows\stack\3.9.3\x64;C:\cabal\bin;C:\ghcup\bin;C:\mingw64\bin;C:\Program Files\dotnet;C:\Program Files\MySQL\MySQL Server 8.0\bin;C:\Program Files\R\R-4.6.0\bin\x64;C:\SeleniumWebDrivers\GeckoDriver;C:\SeleniumWebDrivers\EdgeDriver;C:\SeleniumWebDrivers\ChromeDriver;C:\Program Files (x86)\sbt\bin;C:\Program Files (x86)\GitHub CLI;C:\Program Files\Git\bin;C:\Program Files (x86)\pipx_bin;C:\npm\prefix;C:\hostedtoolcache\windows\go\1.24.13\x64\bin;C:\hostedtoolcache\windows\Python\3.12.10\x64\Scripts;C:\hostedtoolcache\windows\Python\3.12.10\x64;C:\hostedtoolcache\windows\Ruby\3.3.11\x64\bin;C:\Program Files\OpenSSL\bin;C:\tools\kotlinc\bin;C:\hostedtoolcache\windows\Java_Temurin-Hotspot_jdk\17.0.19-10\x64\bin;C:\Program Files\ImageMagick-7.1.2-Q16-HDRI;C:\Program Files\Microsoft SDKs\Azure\CLI2\wbin;C:\ProgramData\kind;C:\ProgramData\Chocolatey\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0;C:\Windows\System32\OpenSSH;C:\Program Files\PowerShell\7;C:\Program Files\Microsoft\Web Platform Installer;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn;C:\Program Files\Microsoft SQL Server\150\Tools\Binn;C:\Program Files\dotnet;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit;C:\Program Files (x86)\WiX Toolset v3.14\bin;C:\Program Files\Microsoft SQL Server\130\DTS\Binn;C:\Program Files\Microsoft SQL Server\140\DTS\Binn;C:\Program Files\Microsoft SQL Server\150\DTS\Binn;C:\Program Files\Microsoft SQL Server\160\DTS\Binn;C:\Program Files\Microsoft SQL Server\170\DTS\Binn;C:\ProgramData\chocolatey\lib\pulumi\tools\Pulumi\bin;C:\Program Files\CMake\bin;C:\Strawberry\c\bin;C:\Strawberry\perl\site\bin;C:\Strawberry\perl\bin;C:\ProgramData\chocolatey\lib\maven\apache-maven-3.9.16\bin;C:\Program Files\Microsoft Service Fabric\bin\Fabric\Fabric.Code;C:\Program Files\Microsoft SDKs\Service Fabric\Tools\ServiceFabricLocalClusterManager;C:\Program Files\nodejs;C:\Program Files\Git\cmd;C:\Program Files\Git\mingw64\bin;C:\Program Files\Git\usr\bin;C:\Program Files\GitHub CLI;C:\tools\php;C:\Program Files (x86)\sbt\bin;C:\Program Files\Amazon\AWSCLIV2;C:\Program Files\Amazon\SessionManagerPlugin\bin;C:\Program Files\Amazon\AWSSAMCLI\bin;C:\Program Files\Microsoft SQL Server\130\Tools\Binn;C:\Program Files\mongosh;C:\Program Files\LLVM\bin;C:\Program Files (x86)\LLVM\bin;C:\Users\runneradmin\.dotnet\tools;C:\Users\runneradmin\.cargo\bin;C:\Users\runneradmin\AppData\Local\Microsoft\WindowsApps" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\stage2\\bin\\rustc.exe" "D:\\a\\rust\\rust\\tests\\ui\\proc-macro\\auxiliary\\api/proc_macro_api_tests.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=C:\\Users\\runneradmin\\.cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=D:\\a\\rust\\rust\\vendor" "--sysroot" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\stage2" "--target=x86_64-pc-windows-gnu" "--check-cfg" "cfg(test,FALSE)" "--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" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\test\\ui\\proc-macro\\test\\auxiliary" "-A" "internal_features" "-A" "incomplete_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\native\\rust-test-helpers" "--edition=2021" "--crate-type" "proc-macro" "--extern" "proc_macro" "-L" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\test\\ui\\proc-macro\\test\\auxiliary"
stdout: none
--- stderr -------------------------------
error[E0658]: `cfg(target_has_reliable_f16)` is experimental and subject to change
##[error]  --> D:\a\rust\rust\tests\ui\proc-macro\auxiliary\api\literal.rs:106:13
   |
LL |     if cfg!(target_has_reliable_f16) {
   |             ^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: add `#![feature(cfg_target_has_reliable_f16_f128)]` to the crate attributes to enable
   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

error[E0658]: `cfg(target_has_reliable_f16)` is experimental and subject to change
##[error]  --> D:\a\rust\rust\tests\ui\proc-macro\auxiliary\api\literal.rs:112:13
   |
LL |     if cfg!(target_has_reliable_f16) {
   |             ^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: add `#![feature(cfg_target_has_reliable_f16_f128)]` to the crate attributes to enable
   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

warning: unexpected `cfg` condition name: `target_has_reliable_f16`
##[warning]  --> D:\a\rust\rust\tests\ui\proc-macro\auxiliary\api\literal.rs:106:13
   |
LL |     if cfg!(target_has_reliable_f16) {
   |             ^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: expected names are: `FALSE` and `test` and 32 more
   = help: to expect this configuration use `--check-cfg=cfg(target_has_reliable_f16)`
   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
   = note: `#[warn(unexpected_cfgs)]` on by default

warning: unexpected `cfg` condition name: `target_has_reliable_f16`
##[warning]  --> D:\a\rust\rust\tests\ui\proc-macro\auxiliary\api\literal.rs:112:13
   |
LL |     if cfg!(target_has_reliable_f16) {
   |             ^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: to expect this configuration use `--check-cfg=cfg(target_has_reliable_f16)`
   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration

warning: the `#![feature]` attribute can only be used at the crate root
##[warning]  --> D:\a\rust\rust\tests\ui\proc-macro\auxiliary\api\literal.rs:3:1
   |
LL | #![feature(f16)]
   | ^^^^^^^^^^^^^^^^
   |
   = help: the crate root is at `D:\a\rust\rust\tests\ui\proc-macro\auxiliary\api/proc_macro_api_tests.rs`
   = note: `#[warn(unused_attributes)]` (part of `#[warn(unused)]`) on by default

warning: the `#![feature]` attribute can only be used at the crate root
##[warning]  --> D:\a\rust\rust\tests\ui\proc-macro\auxiliary\api\literal.rs:4:1
   |
LL | #![feature(cfg_target_has_reliable_f16_f128)]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: the crate root is at `D:\a\rust\rust\tests\ui\proc-macro\auxiliary\api/proc_macro_api_tests.rs`

error: aborting due to 2 previous errors; 4 warnings emitted

For more information about this error, try `rustc --explain E0658`.
------------------------------------------
---

Some tests failed in compiletest suite=ui mode=ui host=x86_64-pc-windows-gnu target=x86_64-pc-windows-gnu
Bootstrap failed while executing `test --stage 2 --skip=compiler --skip=src`
Build completed unsuccessfully in 1:51:31
make: *** [Makefile:126: ci-mingw-x] Error 1
  local time: Sun Jun  7 21:21:33 CUT 2026
  network time: Sun, 07 Jun 2026 21:21:33 GMT
##[error]Process completed with exit code 2.
##[group]Run echo "disk usage:"
echo "disk usage:"

GuillaumeGomez · 2026-06-07T22:34:58Z

@bors try jobs=x86_64-mingw-1

…=<try> Add `_value` API for number literals in proc-macro try-job: x86_64-mingw-1

rust-bors · 2026-06-08T01:26:34Z

☀️ Try build successful (CI)
Build commit: ca0997c (ca0997c1d84db579967006af54f955603d699d43, parent: f20a92ec01483dc5c58e90e246f266bdad822d86)

GuillaumeGomez · 2026-06-08T09:05:56Z

@bors r=Mark-Simulacrum rollup

rust-bors · 2026-06-08T09:05:59Z

📌 Commit 48c52ae has been approved by Mark-Simulacrum

It is now in the queue for this repository.

🌲 The tree is currently closed for pull requests below priority 100. This pull request will be tested once the tree is reopened.

@Urgau

…acro_API, r=Mark-Simulacrum Add `_value` API for number literals in proc-macro Part of rust-lang#136652. This PR adds the `*_value` for numbers (integers and floats). However, `f16` and `f128` are voluntarily left out as they're still unstable. Adding support for them is just a matter of uncommenting two lines, so should be fine. Setting same reviewer as last time. r? @Urgau

…uwer Rollup of 13 pull requests Successful merges: - #147302 (asm! support for the Xtensa architecture) - #148820 (Add very basic "comptime" fn implementation) - #157299 (Fix unstable diagnostics in tests) - #143511 (Improve TLS codegen by marking the panic/init path as cold) - #154608 (Add `_value` API for number literals in proc-macro) - #156762 (xfs support in `test_rename_directory_to_non_empty_directory`) - #157300 (Relax test requirements for consistency) - #157383 (tests: codegen-llvm: Ignore BPF targets in c-variadic-opt) - #157413 (fix: don't suggest .into_iter() for .cloned()/.copied() on non-reference Option) - #157578 (Fix diagnostics for non-exhaustive destructuring assignments (#157553)) - #157587 (explain that the size_of constant also serves to avoid optimizing away 'unused' size_of calls) - #157596 (test: remove ineffective link-extern-crate-with-drop-type test) - #157602 (rustdoc: Remove unnecessary fast path)

@Urgau

Rollup merge of #154608 - GuillaumeGomez:number_value_proc-macro_API, r=Mark-Simulacrum Add `_value` API for number literals in proc-macro Part of #136652. This PR adds the `*_value` for numbers (integers and floats). However, `f16` and `f128` are voluntarily left out as they're still unstable. Adding support for them is just a matter of uncommenting two lines, so should be fine. Setting same reviewer as last time. r? @Urgau

rustbot assigned Urgau Mar 30, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 30, 2026

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rustbot assigned Amanieu and unassigned Urgau Mar 31, 2026

rustbot added the T-libs Relevant to the library team, which will review and decide on the PR/issue. label Mar 31, 2026

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rust-bors Bot pushed a commit that referenced this pull request Jun 6, 2026

Auto merge of #154608 - GuillaumeGomez:number_value_proc-macro_API, r…

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…=<try> Add `_value` API for number literals in proc-macro try-job: x86_64-mingw-1

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Auto merge of #154608 - GuillaumeGomez:number_value_proc-macro_API, r…

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Put f16 conversions behind a cfg check

48c52ae

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rust-bors Bot pushed a commit that referenced this pull request Jun 7, 2026

Auto merge of #154608 - GuillaumeGomez:number_value_proc-macro_API, r…

ca0997c

…=<try> Add `_value` API for number literals in proc-macro try-job: x86_64-mingw-1

rust-bors Bot 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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jun 8, 2026

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Rollup of 9 pull requests #157610

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