Unified: Add static name binding pass

[asgerf]

Adds a static name-binding pass, resolving references to static members, including static-like members such as nested classes.

In addition to resolving static members, I also expect this to be responsible for instance-member lookups in classes.

Commit-by-commit review recommended. The PR also contains a lot of drive-by fixes to the AST mapping (some of it to make tests pass, some of it to make it work on real-world projects).

Name-binding graph

Static name resolution is modelled as a graph with edges between them, using the well-known value/store/read step kinds, in addition to inheritance steps.

Cyclic Dependency on Class Hierarchy

Swift allows unqualified access to inherited members, so for example, Foo below could refer to C.Foo or A.Foo.

import A
class B : C {
    let x: Foo // <-- C.Foo or A.Foo?
}

The base classes themselves can also refer to members inherited by the outer class:

import A
class B : C {
    class D : E { // <-- inherit from C.E or A.E?
        let x: Foo; // <-- E.Foo or C.Foo or A.Foo?
    }
}

Inheritance thus depends on static name resolution, and static name resolution depends on inheritance. We resolve both in a single recursive layer.

Unqualified Lookups

An unqualified identifier gives rise to a read step from each of the scopes it could potentially be found in. In the above example, we'd get three read steps into Foo, corresponding to the three places we might find Foo.

The local name-binding pass has been augmented to support "uncertain scopes" and report back which uncertain scopes a given name access might be found it. This ensures that locally declared names can shadow lookups in outer (uncertain) scopes. For example, a locally declared Foo in the B class would block the read steps corresponding to C and A, while keeping the one from E.

The read steps currently have no priority/ranking, so there is no shadowing supported between uncertain members. There are ways to sharpen the precision a bit here, but I don't expect it to matter much -- let's only do that if we see a need for it.

Cross-file imports

This PR also adds some support for import resolution for projects with Package.swift files.

Future work

• Access levels other than public and "fully private"
• Type-extensions
• More Package.swift fidelity, such as cross-package imports
• Other build system manifests, such as xcode project files
• Support instance-member lookups

[Copilot]

Pull request overview

Adds Swift static name binding across classes, inheritance, modules, and imports, supported by extractor mapping improvements.

Changes:

• Adds static name-binding and uncertain-scope resolution.
• Models SwiftPM targets and cross-file imports.
• Improves Swift AST translation and adds regression fixtures.

Show a summary per file

File	Description
unified/ql/test/library-tests/static-name-binding/unqualified-access.swift	Tests inherited unqualified access.
unified/ql/test/library-tests/static-name-binding/test.swift	Tests static member resolution.
unified/ql/test/library-tests/static-name-binding/test.ql	Implements binding assertions.
unified/ql/test/library-tests/static-name-binding/test.expected	Stores expected test results.
unified/ql/test/library-tests/static-name-binding/package1/Sources/Target2/File3.swift	Defines imported declarations.
unified/ql/test/library-tests/static-name-binding/package1/Sources/Target1/File3.swift	Tests bulk imports.
unified/ql/test/library-tests/static-name-binding/package1/Sources/Target1/File2.swift	Tests scoped imports.
unified/ql/test/library-tests/static-name-binding/package1/Sources/Target1/File1.swift	Tests module visibility.
unified/ql/test/library-tests/static-name-binding/package1/Package.swift	Defines test package targets.
unified/ql/test/library-tests/static-name-binding/inheritance.swift	Tests inherited static members.
unified/ql/test/library-tests/local-name-binding/test.ql	Uses shared comment utilities.
unified/ql/test/library-tests/BasicTest/test.ql	Tests string literal values.
unified/ql/test/library-tests/BasicTest/test.expected	Updates string expectations.
unified/ql/test/library-tests/BasicTest/strings.swift	Adds string fixture.
unified/ql/lib/utils/test/CommentUtil.qll	Extracts inline test metadata.
unified/ql/lib/unified.dbscheme	Adds name-pattern sub-pattern relation.
unified/ql/lib/codeql/unified/internal/StaticNameBinding.qll	Implements static binding graph.
unified/ql/lib/codeql/unified/internal/NameBindingPluginSwift.qll	Adds Swift-specific binding rules.
unified/ql/lib/codeql/unified/internal/NameBindingPlugin.qll	Defines language extension points.
unified/ql/lib/codeql/unified/internal/LocalNameBinding.qll	Exposes declarations and uncertain scopes.
unified/ql/lib/codeql/unified/internal/FacadeAst.qll	Adds file, string, and argument helpers.
unified/ql/lib/codeql/unified/internal/dev/debugStaticNameBindingGraph.ql	Adds static graph visualization.
unified/ql/lib/codeql/unified/internal/dev/debugLocalNameBindingGraph.ql	Renames local graph query.
unified/ql/lib/codeql/unified/internal/Ast.qll	Exposes generated sub-pattern accessors.
unified/ql/lib/codeql/files/FileSystem.qll	Exposes the folder module.
unified/extractor/tests/corpus/swift/types/qualified-type.swift	Adds qualified-type fixture.
unified/extractor/tests/corpus/swift/types/qualified-type.output	Records qualified-type AST.
unified/extractor/tests/corpus/swift/optionals-and-errors/optional-enum-case-binding.swift	Adds optional-pattern fixture.
unified/extractor/tests/corpus/swift/optionals-and-errors/optional-enum-case-binding.output	Records optional-pattern AST.
unified/extractor/tests/corpus/swift/functions/leading-dot-expression-value.output	Updates inferred-type location.
unified/extractor/tests/corpus/swift/functions/leading-dot-expression-call.output	Updates inferred-type location.
unified/extractor/tests/corpus/swift/expressions/array-type-metatype.swift	Adds array metatype fixture.
unified/extractor/tests/corpus/swift/expressions/array-type-metatype.output	Records array metatype AST.
unified/extractor/tests/corpus/swift/expressions/array-type-constructor.swift	Adds array constructor fixture.
unified/extractor/tests/corpus/swift/expressions/array-type-constructor.output	Records array constructor AST.
unified/extractor/tests/corpus/swift/desugar/simple-import-with-single-name.output	Updates bulk-import pattern shape.
unified/extractor/tests/corpus/swift/desugar/import-with-dotted-path-two-parts.output	Updates dotted import shape.
unified/extractor/tests/corpus/swift/desugar/import-with-deeply-nested-path-three-parts.output	Updates deep import shape.
unified/extractor/tests/corpus/swift/control-flow/nested-enum-case-pattern.swift	Adds nested-pattern fixture.
unified/extractor/tests/corpus/swift/control-flow/nested-enum-case-pattern.output	Records nested-pattern AST.
unified/extractor/src/languages/swift/swift.rs	Expands Swift AST translation.
unified/extractor/ast_types.yml	Adds nested name patterns.
shared/namebinding/codeql/namebinding/LocalNameBinding.qll	Adds uncertain-scope support.

Review details

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Suppressed comments (1)

unified/extractor/src/languages/swift/swift.rs:669

• This special case also matches ordinary nested calls, not only enum-case patterns. Because it reconstructs the inner functionCallExpr without its trailingClosure, code such as consume(xs.map { ... }) silently loses the closure. The later generic labeledExpr rule can already preserve the nested constructor pattern because captures are translated with in_pattern; remove this special case so the normal call rule handles all call fields.

                expression: (functionCallExpr
                    calledExpression: @constructor
                    arguments: _* @elements))

• Files reviewed: 42/43 changed files
• Comments generated: 3
• Review effort level: Balanced