Special case some unknown builtin macros

Author: Azoy

lib/ASTGen/Sources/ASTGen/Macros.swift

@@ -255,6 +255,20 @@ func checkMacroDefinition(
         case "ExternalMacro":
           return Int(BridgedMacroDefinitionKind.builtinExternalMacro.rawValue)
 
+        // These builtins don't exist, but are put into the standard library at
+        // least for documentation purposes right now. Don't emit a warning for
+        // them, but do fail operation.
+        case "FileIDMacro",
+             "FilePathMacro",
+             "FileMacro",
+             "FunctionMacro",
+             "LineMacro",
+             "ColumnMacro",
+             "DSOHandleMacro",
+             "WarningMacro",
+             "ErrorMacro":
+          return -1
+
         default:
           // Warn about the unknown builtin.
           let srcMgr = SourceManager(cxxDiagnosticEngine: diagEnginePtr)

stdlib/public/core/Macros.swift

@@ -25,8 +25,6 @@
 public macro externalMacro<T>(module: String, type: String) -> T =
   Builtin.ExternalMacro
 
-#if false
-
 // File and path-related information
 
 /// Produces a unique identifier for the given source file, comprised of
@@ -73,6 +71,4 @@ public macro warning(_ message: String) = Builtin.WarningMacro
 @freestanding(declaration)
 public macro error(_ message: String) = Builtin.ErrorMacro
 
-#endif // false
-
 #endif // $Macros && hasAttribute(attached)