Eh, just borrow the implementation from TSC

Author: grynspan

Sources/TestingMacros/CMakeLists.txt

@@ -99,9 +99,9 @@ target_sources(TestingMacros PRIVATE
   Support/AvailabilityGuards.swift
   Support/CommentParsing.swift
   Support/ConditionArgumentParsing.swift
-  Support/CRC32.swift
   Support/DiagnosticMessage.swift
   Support/DiagnosticMessage+Diagnosing.swift
+  Support/SHA256.swift
   Support/SourceCodeCapturing.swift
   Support/SourceLocationGeneration.swift
   Support/TestContentGeneration.swift

Sources/TestingMacros/ConditionMacro.swift

@@ -447,17 +447,15 @@ extension ExitTestConditionMacro {
       context.diagnose(.captureClauseUnsupported(captureClause, in: closureExpr, inExitTest: macro))
     }
 
-    var exitTestID: (UInt64, UInt64)
+    let exitTestID: (UInt64, UInt64)
     if let sourceLocation = context.location(of: macro, at: .afterLeadingTrivia, filePathMode: .fileID),
        var fileID = sourceLocation.file.as(StringLiteralExprSyntax.self)?.representedLiteralValue,
        let line = sourceLocation.line.as(IntegerLiteralExprSyntax.self)?.representedLiteralValue,
        let column = sourceLocation.column.as(IntegerLiteralExprSyntax.self)?.representedLiteralValue {
       exitTestID.0 = fileID.withUTF8(make64BitHash)
       exitTestID.1 = (UInt64(line) << 32) | UInt64(column)
     } else {
-      // TODO: use UUID() here if we can link to Foundation?
-      exitTestID.0 = .random(in: 0 ... .max)
-      exitTestID.1 = .random(in: 0 ... .max)
+      fatalError("Could not determine the source location of this exit test. Please file a bug report at https://github.com/swiftlang/swift-testing/issues/new")
     }
     let exitTestIDExpr: ExprSyntax = "(\(IntegerLiteralExprSyntax(exitTestID.0, radix: .hex)), \(IntegerLiteralExprSyntax(exitTestID.1, radix: .hex)))"
 

Sources/TestingMacros/Support/Additions/MacroExpansionContextAdditions.swift

@@ -66,7 +66,7 @@ extension MacroExpansionContext {
     let hashValue = make64BitHash(identifierCharacters.utf8)
     let suffix = String(hashValue, radix: 16, uppercase: false)
 
-    // If the caller did not specify a prefix and the CRC32 value starts with a
+    // If the caller did not specify a prefix and the hash value starts with a
     // digit, include a single-character prefix to ensure that Swift's name
     // demangling still works correctly.
     var prefix = prefix