[LibraryImport] Naming `string` parameter `retVal` in import with `string` return value results in `CS0128`
Nobody has claimed this yet.
Assessment
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Newbie friendliness
- 65/100
Research direction
Start by tracing the LibraryImport generator's handling of string return-value and parameter buffers using the C# reproduction in the issue. Check how local names are derived for the return value and parameters, then verify that the retVal example no longer produces CS0128 and that existing generated interop cases remain valid.
Written by the indexing model from the issue text.
Description
Description
The LibraryImport generator uses byte* __retVal_native as the name for the local return value buffer variable. It uses byte* __parameterName_native as the name for the local input buffer variable. If the parameter is named retVal, this results in two locals named __retVal_native.
This can potentially be solved by simply using __retVal_native for the return value local variable and __p_retVal_native for parameter local variables.
Reproduction Steps
partial class C
{
[LibraryImport("_", StringMarshalling = StringMarshalling.Utf8)]
private static partial string M(string retVal);
}
Expected behavior
The generator does not use the same local variable names for both parameters and return values.
Actual behavior
It does.
Regression?
No response
Known Workarounds
Don't name the parameter retVal.
Configuration
10.0.100-preview.4.25258.110
Other information
No response
- Dominant language
- C#
- Stars
- 18.3k
- Forks
- 5.6k
- PR merge metrics
- PR metrics pending
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
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