_SwiftSyntaxGenericTestSupport uses key paths which are unavailable in Embedded Swift

[coenttb]

Description

When building a package that depends on swift-syntax with the Embedded Swift SDK, compilation fails because _SwiftSyntaxGenericTestSupport uses key path syntax which is not available in Embedded Swift.

Error

error: cannot use key path in embedded Swift
   |
18 |       .map { $0.droppingLast(while: \.isWhitespace) }
   |                                     `- error: cannot use key path in embedded Swift

Location

Sources/_SwiftSyntaxGenericTestSupport/String+TrimmingTrailingWhitespace.swift:18

Suggested Fix

Replace key path with explicit closure:

// Before
.map { $0.droppingLast(while: \.isWhitespace) }

// After
.map { $0.droppingLast(while: { $0.isWhitespace }) }

Environment

• Swift 6.2.3 (swift-6.2.3-RELEASE)
• SDK: swift-6.2.3-RELEASE_wasm-embedded
• Build command: swift build --swift-sdk swift-6.2.3-RELEASE_wasm-embedded

Notes

This only affects test support code, not the core SwiftSyntax library. However, downstream packages that include swift-syntax as a dependency cannot build for Embedded Swift targets even if they don't use the test support module, because SwiftPM builds all targets.