code: private Stmt.Debug parseDebugStatement(EnclosingScope scope) {
  		int start = index;
  		// Match the debug keyword
  		match(Debug);
  		// Parse the expression to be printed
  		Expr e = parseExpression(scope, false);
  		// Finally, at this point we are expecting a new-line to signal the
  		// end-of-statement.
  		int end = index;
  		matchEndLine();
  		// Done.
  		return annotateSourceLocation(new Stmt.Debug(e), start, end-1);
  	}
docs: Parse a debug statement, which is of the form:
  
  <pre>
  DebugStmt ::= "debug" Expr
  </pre>
  
  @param scope
  The enclosing scope for this statement, which determines the
  set of visible (i.e. declared) variables and also the current
  indentation level.
  
  @see wyc.lang.Stmt.Debug
  @return