Getting error when using Maps

[thomsong]

I'm getting the following error when trying to use a Map

panic: interface conversion: interface {} is nil, not *ast.ClassType

go run . run -f Test.cls -a "Test#testMap"

public class Test {
    public static void testMap() {
        Map<String,String> info = new Map<String,String>();
        info.put('age', '5');
        info.put('name', 'Doug');
        System.debug(info.keySet());
    }
}

[thomsong]

Additional Error Info

panic: interface conversion: interface {} is nil, not *ast.ClassType

goroutine 1 [running]:
github.com/tzmfreedom/land/compiler.(*TypeChecker).VisitMethodInvocation(0x14000718ba0, 0x14000411340)
    ./land-master/compiler/type_checker.go:322 +0x7d4
github.com/tzmfreedom/land/ast.(*MethodInvocation).Accept(0x10?, {0x1054c60f0?, 0x14000718ba0?})
    ./land-master/ast/node.go:821 +0x30
github.com/tzmfreedom/land/compiler.(*TypeChecker).VisitBlock.func1()
    ./land-master/compiler/type_checker.go:778 +0x9c
github.com/tzmfreedom/land/compiler.(*TypeChecker).NewEnv(0x14000718ba0, 0x1400082cf80)
    ./land-master/compiler/type_checker.go:904 +0xe4
github.com/tzmfreedom/land/compiler.(*TypeChecker).VisitBlock(0x1053cb200?, 0x140008573b0?)
    ./land-master/compiler/type_checker.go:776 +0x58
github.com/tzmfreedom/land/ast.(*Block).Accept(...)
    ./land-master/ast/node.go:1084
github.com/tzmfreedom/land/compiler.(*TypeChecker).VisitMethod(0x14000718ba0, 0x1400031f810)
    ./land-master/compiler/type_checker.go:879 +0x344
github.com/tzmfreedom/land/compiler.(*TypeChecker).VisitClassType(0x14000718ba0, 0x140003d1440)
    ./land-master/compiler/type_checker.go:71 +0xa6c
main.semanticAnalysis(0x140003d1440?)
    ./land-master/commands.go:497 +0x34c
main.buildAllFile({0x14000437b30, 0x1, 0x1052344c7?})
    ./land-master/commands.go:761 +0x2a4
main.glob..func11(0x14000328840)
    ./land-master/commands.go:341 +0x74
gopkg.in/urfave/cli%2ev1.HandleAction({0x1053a9300?, 0x10549fab8?}, 0x3?)
    ./go/pkg/mod/gopkg.in/urfave/[email protected]/app.go:490 +0x6c
gopkg.in/urfave/cli%2ev1.Command.Run({{0x105233eb7, 0x3}, {0x0, 0x0}, {0x0, 0x0, 0x0}, {0x0, 0x0}, {0x0, ...}, ...}, ...)
    ./go/pkg/mod/gopkg.in/urfave/[email protected]/command.go:210 +0x68c
gopkg.in/urfave/cli%2ev1.(*App).Run(0x14000103520, {0x14000134120, 0x6, 0x6})
    ./go/pkg/mod/gopkg.in/urfave/[email protected]/app.go:255 +0x758
main.main()
    ./land-master/land.go:37 +0x510
exit status 2

[tzmfreedom]

@thomsong Thank you for reporting issue !
I fixed in #3