Check:

RewriteRuleElementStream is in CSharp3 not a generic type!

Look for Get() to turn into indexers!

API CHANGES FROM ANTRLR 3.1 to ANTLR 3.2

Removed any obsolete API. Lots of properties and methods have been turned virtual. Constants in UPPERCASE_ONLY have been turned into UppercaseOnly.

Antlr.Runtime.Tree.Tree renamed to Antlr.Runtime.Tree.TreeConstants

Antlr.Runtime.BaseRecognizer.Failed() has been turned into a property
Antlr.Runtime.BaseRecognizer.NEXT_TOKEN_RULE_NAME renamed to Antlr.Runtime.BaseRecognizer.NextTokenRuleName
Antlr.Runtime.BaseRecognizer.MEMO_RULE_FAILED renamed to Antlr.Runtime.BaseRecognizer.MemoRuleFailed
Antlr.Runtime.BaseRecognizer.MEMO_RULE_UNKNOWN renamed to Antlr.Runtime.BaseRecognizer.MemoRuleUnknown
Antlr.Runtime.BaseRecognizer.INITIAL_FOLLOW_STACK_SIZE renamed to Antlr.Runtime.BaseRecognizer.InitialFollowStackSize
Antlr.Runtime.BaseRecognizer.DEFAULT_TOKEN_CHANNEL renamed to Antlr.Runtime.BaseRecognizer.DefaultTokenChannel
Antlr.Runtime.BaseRecognizer.HIDDEN renamed to Antlr.Runtime.BaseRecognizer.Hidden
Antlr.Runtime.BaseRecognizer.Input has been removed.

Antlr.Runtime.Parser.Input - return type has been changed to ITokenStream

Antlr.Runtime.Lexer.Input - return type has been changed to ICharStream

Antlr.Runtime.TreeParser - return type has been changed to ITreeNodeStream

Antlr.Runtime.RuleReturnScope - removed setters from properties

Antlr.Runtime.ParserRuleReturnScope - removed setters from properties
Antlr.Runtime.ParserRuleReturnScope.start has been made public
Antlr.Runtime.ParserRuleReturnScope.stop has been made public

Antlr.Runtime.TreeRuleReturnScope - removed setter from property

Antlr.Runtime.Tree.RewriteRuleElementStream is no longer generic (this causes appropriate changes to the derived classes). Usually T and SpecializingType have been replaced with "object".
Antlr.Runtime.Tree.RewriteRuleElementStream.HasNext has been turned into a property
Antlr.Runtime.Tree.RewriteRuleElementStream._Next() has been merged with NextTree()
Antlr.Runtime.Tree.RewriteRuleElementStream.Dup() has been added

Antlr.Runtime.Tree.RewriteRuleTokenStream.Dup() has been added

Antlr.Runtime.Tree.RewriteRuleTokenStream.Dup() has been added

Antlr.Runtime.CharStreamConstants.EOF has been renamed to EndOfFile

Antlr.Runtime.Tree.ITreeAdaptor.GetNilNode has been turned into property Nil (implementing classes followed)