Merge pull request #209 from tonyfreeman/signature

Fix XCTAssertThrowsError function signature
diff --git a/Sources/XCTest/Public/XCTAssert.swift b/Sources/XCTest/Public/XCTAssert.swift
index f16b10b..eaa0733 100644
--- a/Sources/XCTest/Public/XCTAssert.swift
+++ b/Sources/XCTest/Public/XCTAssert.swift
@@ -306,7 +306,7 @@
     }
 }
 
-public func XCTAssertThrowsError<T>(_ expression: @autoclosure () throws -> T, _ message: String = "", file: StaticString = #file, line: UInt = #line, _ errorHandler: (_ error: Swift.Error) -> Void = { _ in }) {
+public func XCTAssertThrowsError<T>(_ expression: @autoclosure () throws -> T, _ message: @autoclosure () -> String = "", file: StaticString = #file, line: UInt = #line, _ errorHandler: (_ error: Swift.Error) -> Void = { _ in }) {
     _XCTEvaluateAssertion(.throwsError, message: message, file: file, line: line) {
         var caughtErrorOptional: Swift.Error?
         do {