code: private Stmt.Assert parseAssertStatement(EnclosingScope scope) {
  		int start = index;
  		// Match the assert keyword
  		match(Assert);
  		// Parse the expression to be printed
  		Expr e = parseLogicalExpression(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.Assert(e), start);
  	}
docs: Parse an assert statement, which is of the form:
  
  <pre>
  AssertStmt ::= "assert" 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.Assert
  @return