Sensible error message for mistakes from C#

I just wrote code like this:

for (subDit in Directory.GetDirectories(dir)):

Which resulted in the following error, which is both spooky an unhelpful.

replace.boo(5,8): BCE0044: Boo.Lang.Compiler.CompilerError: 'expecting "ID", found '(''. ---> replace.boo:5:8: expecting "ID", found '('
— End of inner exception stack trace —
BCE0042: Boo.Lang.Compiler.CompilerError: Error reading from 'replace.boo': 'null reference for: item'. ---> System.ArgumentException: null reference for: it
em
at Boo.Lang.Compiler.Ast.NodeCollection.AssertNotNull(String descrip, Object o)
at Boo.Lang.Compiler.Ast.NodeCollection.Initialize(Node item)
at Boo.Lang.Compiler.Ast.NodeCollection.AddNode(Node item)
at Boo.Lang.Compiler.Ast.Impl.DeclarationCollectionImpl.Add(Declaration item)
at Boo.Lang.Parser.BooParserBase.declaration_list(DeclarationCollection dc)
at Boo.Lang.Parser.BooParserBase.for_stmt()
at Boo.Lang.Parser.BooParserBase.stmt(StatementCollection container)
at Boo.Lang.Parser.BooParserBase.block(StatementCollection container)
at Boo.Lang.Parser.BooParserBase.method(TypeMemberCollection container)
at Boo.Lang.Parser.BooParserBase.type_member(TypeMemberCollection container)
at Boo.Lang.Parser.BooParserBase.start(CompileUnit cu)
at Boo.Lang.Parser.BooParser.ParseModule(Int32 tabSize, CompileUnit cu, String readerName, TextReader reader, ParserErrorHandler errorHandler)
at Boo.Lang.Parser.BooParsingStep.Run()
— End of inner exception stack trace —