TreePatternTest in C#

Program.cs

namespace TreePatternTest
{
    using System;
    using System.Collections.Generic;
    using Antlr4.Runtime;
    using Antlr4.Runtime.Tree;
    using Antlr4.Runtime.Tree.Pattern;

    class Program
    {
        static void Main(string[] args)
        {
            string input = "3*4*5;";
            var charStream = new AntlrInputStream(input);
            var lexer = new X6Lexer(charStream);
            var tokenStream = new CommonTokenStream(lexer);
            var parser = new X6Parser(tokenStream);
            X6Parser.SContext compileUnit = parser.s();

            string pattern = "<expr> * <expr> * <expr>";
            var parseTreePattern = parser.CompileParseTreePattern(pattern, X6Parser.RULE_expr);

            IList<ParseTreeMatch> matches = parseTreePattern.FindAll(compileUnit, "//expr");
            foreach (var match in matches)
            {
                Console.WriteLine("Match: {0}", match.GetTree().GetText());
                foreach (KeyValuePair<string, IList<IParseTree>> pair in match.GetLabels())
                {
                    Console.WriteLine("  Label: {0}", pair.Key);
                    foreach (IParseTree parseTree in pair.Value)
                    {
                        Console.WriteLine("    {0}", parseTree.GetText());
                    }
                }
            }
        }
    }
}

X6.g4

grammar X6;

/*
 * Parser Rules
 */

s
	:	expr ';' EOF
	;

expr
	:	expr '*' expr
	|	expr '=' expr
	|	ID
	|	INT
	;

/*
 * Lexer Rules
 */

ID
	:	[a-z]+
	;

INT
	:	[0-9]+
	;

WS
	:	' ' -> channel(HIDDEN)
	;

Fixed for Antlr 4.9.2

namespace TreePatternTest
{
    using System;
    using System.Collections.Generic;
    using Antlr4.Runtime;
    using Antlr4.Runtime.Tree;
    using Antlr4.Runtime.Tree.Pattern;

    class Program
    {
        static void Main(string[] args)
        {
            string input = "3*4*5;";
            var charStream = new AntlrInputStream(input);
            var lexer = new X6Lexer(charStream);
            var tokenStream = new CommonTokenStream(lexer);
            var parser = new X6Parser(tokenStream);
            X6Parser.SContext compileUnit = parser.s();

            string pattern = "<expr> * <expr> * <expr>";
            var parseTreePattern = parser.CompileParseTreePattern(pattern, X6Parser.RULE_expr);

            IList<ParseTreeMatch> matches = parseTreePattern.FindAll(compileUnit, "//expr");
            foreach (var match in matches)
            {
                Console.WriteLine("Match: {0}", match.Tree.GetText());
                foreach (KeyValuePair<string, IList<IParseTree>> pair in match.Labels)
                {
                    Console.WriteLine("  Label: {0}", pair.Key);
                    foreach (IParseTree parseTree in pair.Value)
                    {
                        Console.WriteLine("    {0}", parseTree.GetText());
                    }
                }
            }
        }
    }
}