Fix Atomic::load() being incorrectly marked as mutating

[Copilot]

• Explore repository structure and understand the issue
• Create a test case to reproduce the issue (Atomic::load in property getter)
• Verify the issue exists in current code
• Fix the issue by changing [__ref] to [constref] in core.meta.slang line 3744
• Build the code to verify fix compiles
• Run the test to verify the fix works
• Run formatting script
• Run CodeQL security check
• Final verification - all tests passing
• Address reviewer feedback on test

Summary

Fixed the issue where Atomic<T>::load() was incorrectly marked as mutating, preventing it from being called in property getters or other const contexts.

Changes made:

1. Changed [__ref] to [constref] attribute on Atomic<T>::load() method in source/slang/core.meta.slang line 3744
2. Added regression test in tests/language-feature/atomic-load-property.slang to verify the fix (updated based on reviewer feedback)

The fix is minimal and surgical - only changing the single attribute that was incorrect. All existing tests continue to pass.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Atomic::load is considered mutating</issue_title>
<issue_description># Issue Description
A clear and concise description of what the bug is.
Before filing the issue, please make sure the bug can be reproduced with the latest release of Slang.
it seems that the Atomic::load method is considered mutating when it shoudl be non mutating.

Reproducer Code

Atomic<float> number;

property float value { get { return number.load(); } }

Expected Behavior

I expected the following code tocompile since it shouldnt mutate.

Actual Behavior

It gives a compiler error, which I believe is incorrect behaviour.

Environment

Windows
Latest slangc version 2025.19.1

Additional context

Nope, this might be intended behaviour in which case can you please elucidate this?</issue_description>

Comments on the Issue (you are @copilot in this section)

@csyonghe Looks like an error in core.meta.slang:3744, which should be: ``` [constref] T load(MemoryOrder order = MemoryOrder.Relaxed); ``` instead of ``` [__ref] T load(MemoryOrder order = MemoryOrder.Relaxed); ```

Fixes #8759

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[csyonghe]

I don't think this test is correct. Should be:

//TEST:COMPARE_COMPUTE(filecheck-buffer=CHECK):-output-using-type

struct AtomicCounter
{
      Atomic<uint> sharedNumber;
      property uint value { get { return sharedNumber.load(); } }
}

//TEST_INPUT: set gBuffer = ubuffer(data=[10 0 0 0], stride=4)
StructuredBuffer<AtomicCounter> gBuffer;

//TEST_INPUT: set outputBuffer = out ubuffer(data=[0 0 0 0], stride=4)
RWStructuredBuffer<uint> outputBuffer;

[numthreads(1,1,1)]
void computeMain()
{
    // CHECK: 10
    outputBuffer[0] = gBuffer[0].value;
}

[Copilot]

Updated the test as suggested in commit d82ddf2.

[csyonghe]

@copilot fix the test.

[Copilot]

@copilot fix the test.

Fixed the test as suggested in commit d82ddf2.

[aidanfnv]

Looks good to me.