Detect 'Is.NaN' with unsupported types.#942
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manfred-brands merged 2 commits intomasterfrom Oct 31, 2025
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Pull Request Overview
This PR enhances the EqualToIncompatibleTypes analyzer to detect when Is.NaN or Is.Not.NaN constraints are used with non-floating-point types (e.g., int, decimal, string). Since only float and double types support NaN values, using this constraint with other types will always fail and represents a test logic error.
Key Changes:
- Added detection logic for
Is.NaNconstraint usage with unsupported types - Added null-safety checks and nullable type unwrapping for the actual type
- Added comprehensive test coverage for both valid and invalid uses of
Is.NaN
Reviewed Changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| src/nunit.analyzers/EqualToIncompatibleTypes/EqualToIncompatibleTypesAnalyzer.cs | Implements null-safety checks, nullable type unwrapping, and detection logic for Is.NaN used with non-float/double types |
| src/nunit.analyzers.tests/EqualToIncompatibleTypes/EqualToIncompatibleTypesAnalyzerTests.cs | Adds test cases validating the analyzer correctly allows Is.NaN with float/double/nullable double and flags usage with decimal, int, and string |
| documentation/NUnit2021.md | Documents the new detection capability with an example of invalid NaN testing on integer types |
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mikkelbu
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Oct 30, 2025
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mikkelbu
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Nice and simple solution (simpler than I would have expected). I've only added a couple of comments, but I'm happy to merge it when you are
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Fixes #929