C#: Correct printing of returns via out/ref parameters in model generation. #19114
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Pull Request Overview
This PR fixes the model generation to correctly print return flows via out/ref parameters and addresses an issue with ref parameter usage in method declarations. The changes include:
- Updating model summaries for methods that handle out and ref parameters.
- Fixing the incorrect summary flow for methods using ref parameters.
- Introducing a new ParameterModifiers class with methods to test the updated behavior.
Files not reviewed (2)
- csharp/ql/src/utils/modelgenerator/internal/CaptureModels.qll: Language not supported
- shared/mad/codeql/mad/modelgenerator/internal/ModelGeneratorImpl.qll: Language not supported
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| // neutral=Models;ParameterModifiers;RefParamUse;(System.Object);summary;df-generated | ||
| public void RefParamUse(ref object value) | ||
| { | ||
| var b = value is null; |
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The variable 'b' is assigned but never used; consider removing it or using it meaningfully to avoid confusion.
Suggested change
| var b = value is null; | |
| // The variable 'b' was removed as it was unused. |
hvitved
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Mar 27, 2025
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This is addressing the issue https://github.com/github/codeql-csharp-team/issues/474 reported by @MathiasVP.
There are two note-worthy consequences of this
outorrefparameter will now correctly targetArgument[...]instead ofReturnValue.refparameter and a use of therefparameter in the callable declaration would lead to an incorrect summary, as there would be flow from the parameter node to the SSA definition corresponding to the parameter. This is fixed with this change.