When/how during compilation are bindings attached?

[Arvydas Silanskas <nma.arvydas.silanskas@gmail.com>]

I'm working with tracking of definition place for identifiers. For some
reason, found identifiers don't have binding information attached, do you
have insight why that could be? Here is standalone snippet (mostly based on
LSP in kawa source tree)

import gnu.expr.Compilation;
import gnu.expr.ExpExpVisitor;
import gnu.expr.Expression;
import gnu.expr.ReferenceExp;
import gnu.kawa.io.CharArrayInPort;
import gnu.text.SourceMessages;
import kawa.standard.Scheme;

import java.io.IOException;
import java.util.Arrays;
import java.util.stream.Collectors;

public class TestModuleBinding {

    public static void main(String[] args) throws IOException {
        var source = new String[]{
                "(define (a) 1)",
                "(a)"
        };
        var sourceCode =
Arrays.stream(source).collect(Collectors.joining("\n"));
        int line = 2;
        int col = 2;
        var language = Scheme.getR7rsInstance();
        var inPort = CharArrayInPort.make(sourceCode);
        var sourceMessages = new SourceMessages();
        Compilation compilation = language.parse(inPort, sourceMessages,
Scheme.PARSE_FOR_EVAL);
        language.resolve(compilation);

        class FindDecl extends ExpExpVisitor<Void> {

            @Override
            protected Expression visitReferenceExp(ReferenceExp exp, Void
ignored) {
                var expLine = exp.getLineNumber();
                var expCol = exp.getColumnNumber();
                if (line == expLine && col == expCol) {
                    if (!exp.getName().equals("a"))
                        throw new RuntimeException("Expected 'a'");
                    if (exp.getBinding() == null)
                        throw new RuntimeException("Expected non-null
binding");
                }
                return super.visitReferenceExp(exp, ignored);
            }
        }
        FindDecl fd  = new FindDecl();
        var module = compilation.getModule();
        fd.visit(module, null);
    }
}

Arvydas