Basic import std example does not work with Meson 1.10.0 or 1.11 under Mac

[germandiagogomez]

Describe the bug

A simple Meson example with import std seems to be failing

To Reproduce

Please find the attached file and replace toolchain file as appropriate if needed (using clang homebrew MacOS).

import-std-basic.zip

meson setup --native-file clang.ini build
meson compile -C build

** Output**
The Meson build system
Version: 1.11.0
Source dir: /Users/germandiago/import-std-basic
Build dir: /Users/germandiago/import-std-basic/build
Build type: native build
Project name: import-std-basic
Project version: 0.1
C++ compiler for the host machine: /usr/local/Cellar/llvm/22.1.3/bin/clang++ (clang 22.1.3 "Homebrew clang version 22.1.3")
C++ linker for the host machine: /usr/local/Cellar/llvm/22.1.3/bin/clang++ ld64 1167.5
Host machine cpu family: x86_64
Host machine cpu: x86_64
Build targets in project: 1

import-std-basic 0.1

User defined options
Native files: clang.ini

Found ninja-1.13.2 at /usr/local/bin/ninja

meson compile -C build
INFO: autodetecting backend as ninja
INFO: calculating backend command to run: /usr/local/bin/ninja -C /Users/germandiago/import-std-basic/build
ninja: Entering directory `/Users/germandiago/import-std-basic/build'
[1/2] Compiling C++ object import-std-basic.p/import_std_basic.cpp.o
FAILED: [code=1] import-std-basic.p/import_std_basic.cpp.o
/usr/local/Cellar/llvm/22.1.3/bin/clang++ -Iimport-std-basic.p -I. -I.. -I/usr/local/opt/llvm/include -fdiagnostics-color=always -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_FAST -Wall -Winvalid-pch -Wextra -Wpedantic -std=c++23 -O0 -g -MD -MQ import-std-basic.p/import_std_basic.cpp.o -MF import-std-basic.p/import_std_basic.cpp.o.d -o import-std-basic.p/import_std_basic.cpp.o -c ../import_std_basic.cpp
../import_std_basic.cpp:1:8: fatal error: module 'std' not found
1 | import std;
| ~~~~~~~^~~
1 error generated.

system parameters

• Is this a cross build or just a plain native build (for the same computer)? No
• what operating system (e.g. MacOS Catalina, Windows 10, CentOS 8.0, Ubuntu 18.04, etc.) MacOS
• what Python version are you using e.g. 3.8.0
• what meson --version - Tried 1.10.0 and 1.11.0
• what ninja --version if it's a Ninja build -- 1.13.2

clang toolchain:

Homebrew clang version 22.1.3
Target: x86_64-apple-darwin24.3.0
Thread model: posix
InstalledDir: /usr/local/Cellar/llvm/22.1.3/bin
Configuration file: /usr/local/Cellar/llvm/22.1.3/etc/clang/x86_64-apple-darwin24.cfg

[jpakkane]

[1/2] Compiling C++ object import-std-basic.p/import_std_basic.cpp.o

The problem here is that compiling the standard library module is not done. Probably the code assumes that clang + macOS means that modules are not supported because xcode does not support it.