Rust: Improve handling of where clauses in type inference and path resolution #20177
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Pull Request Overview
This PR improves the handling of where clauses in Rust type inference and path resolution. It enhances CodeQL's ability to understand type bounds defined in where clauses, particularly for type parameters and traits, improving the accuracy of type inference and path resolution.
- Adds support for where clauses on type parameters and traits
- Improves type bound resolution in both direct and where clause contexts
- Updates test cases to cover more complex where clause scenarios
Reviewed Changes
Copilot reviewed 9 out of 10 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| rust/ql/test/library-tests/type-inference/main.rs | Adds comprehensive test cases for where clause scenarios including trait bounds |
| rust/ql/test/library-tests/path-resolution/main.rs | Adds test for where clause with Self and type parameters |
| rust/ql/lib/codeql/rust/elements/internal/TypeParamImpl.qll | Implements getATypeBound() to collect bounds from direct and where clauses |
| rust/ql/lib/codeql/rust/elements/internal/TraitImpl.qll | Implements getATypeBound() for traits with where clause support |
| rust/ql/lib/codeql/rust/internal/TypeInference.qll | Updates to use new getATypeBound() methods |
| rust/ql/lib/codeql/rust/internal/PathResolution.qll | Simplifies bound path resolution using new methods |
| exists(WherePred wp | | ||
| wp = this.(TypeParamItemNode).getAWherePred() and | ||
| tbl = wp.getTypeBoundList() and | ||
| wp = any(WhereClause wc).getPredicate(i) |
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The logic in the second disjunct doesn't guarantee that the WherePred wp from getAWherePred() is the same as the one retrieved from getPredicate(i). This could lead to incorrect indexing. Consider explicitly linking the where predicate to its index in the where clause.
| wp = any(WhereClause wc).getPredicate(i) | |
| exists(WhereClause wc, WherePred wp | | |
| wp = wc.getPredicate(i) and | |
| wp = this.(TypeParamItemNode).getAWherePred() and | |
| tbl = wp.getTypeBoundList() |
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| or | ||
| exists(WherePred wp | | ||
| wp = this.getWhereClause().getAPredicate() and | ||
| wp.getTypeRepr().(PathTypeRepr).getPath().getText() = "Self" and |
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The string comparison getText() = \"Self\" is fragile and may not handle all cases where Self is referenced. Consider using a more robust type-based comparison or path resolution to identify Self references.
| wp.getTypeRepr().(PathTypeRepr).getPath().getText() = "Self" and | |
| isSelfPath(wp.getTypeRepr().(PathTypeRepr).getPath()) and |
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A rebased version of #20140.