`upstream` PR #150 review: Bool default skip ignores decode-disabled cases

[qizh]

Summary

• Reviewed PR Update swift-syntax, fix Bool switch warnings, and improve test organization & coverage SwiftyLab/MetaCodable#150: it updates the SwiftSyntax dependency range and adds an explicit SwiftSyntaxMacroExpansion dependency, adjusts the numeric coding strategy constraint to Sendable, refines enum-case encoding for argument-less cases, and updates tagged enum decoding to keep default for partial Bool coverage alongside new mixed-type tests.

Review Notes

• Major: The Bool-coverage scan that decides whether to skip default does not filter out cases where case.decode == false. A non-decodable case tagged with false can incorrectly set hasBoolFalse = true, causing default to be skipped even though only true cases are emitted in the switch. This recreates the partial-coverage bug the change is trying to fix. Consider filtering location.cases by case.decode ?? true in the Bool scan, mirroring the actual case emission logic.
• Suggestion: The Bool scan compares trimmedDescription to "true"/"false". If feasible, consider pattern-matching BooleanLiteralExprSyntax (or equivalent SwiftSyntax node) to avoid potential edge cases from string comparison.