[swift-dev] Building Toolchain Fails

[Daniel Eggert]

I'm seeing this when trying to build a toolchain off master:

% ./utils/update-checkout --clone-with-ssh
% caffeinate ./utils/build-toolchain local.swift

[...]

--- Running tests for swiftpm ---
+ /Users/deggert/Desktop/Swift/swiftpm/Utilities/bootstrap --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk -v --swiftc=/Users/deggert/Desktop/Swift/build/buildbot_osx/swift-macosx-x86_64/bin/swiftc --sbt=/Users/deggert/Desktop/Swift/build/buildbot_osx/llbuild-macosx-x86_64/bin/swift-build-tool --build=/Users/deggert/Desktop/Swift/build/buildbot_osx/swiftpm-macosx-x86_64 test
--- bootstrap: note: building stage1: /Users/deggert/Desktop/Swift/build/buildbot_osx/llbuild-macosx-x86_64/bin/swift-build-tool -f /Users/deggert/Desktop/Swift/build/buildbot_osx/swiftpm-macosx-x86_64/.bootstrap/build.swift-build -v
--- bootstrap: note: building self-hosted 'swift-build': env SWIFT_EXEC=/Users/deggert/Desktop/Swift/build/buildbot_osx/swiftpm-macosx-x86_64/debug/swiftc SWIFT_BUILD_PATH=/Users/deggert/Desktop/Swift/build/buildbot_osx/swiftpm-macosx-x86_64 SYSROOT=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk /Users/deggert/Desktop/Swift/build/buildbot_osx/swiftpm-macosx-x86_64/debug/swift-build-stage1 -Xlinker -rpath -Xlinker @executable_path/../lib/swift/macosx
Compiling Swift Module 'UtilityTestSuite' (8 sources)
Compiling Swift Module 'TransmuteTestSuite' (2 sources)
Compiling Swift Module 'ManifestParserTestSuite' (4 sources)
Compiling Swift Module 'PackageDescriptionTestSuite' (2 sources)
Compiling Swift Module 'GetTestSuite' (4 sources)
/Users/deggert/Desktop/Swift/swiftpm/Tests/ManifestParser/ManifestTests.swift:54:13: error: expression type 'Void' (aka '()') is ambiguous without more context
            XCTAssertEqual(manifest.package.targets, [])
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[...]

error: exit(1): /Users/deggert/Desktop/Swift/build/buildbot_osx/swiftpm-macosx-x86_64/debug/swift-build-tool -f /Users/deggert/Desktop/Swift/build/buildbot_osx/swiftpm-macosx-x86_64/debug.yaml test
--- bootstrap: error: tests failed with exit status 1
./utils/build-script: command terminated with a non-zero exit status 1, aborting
./utils/build-script: command terminated with a non-zero exit status 1, aborting