@Override
    protected Type typecheckValue(Scope<Type> scope) {
        return context("while typechecking the error", error, () -> error.typeCheck(scope).expectStringType());
    }
Gets the error expression to return when reaching this rule.

@return the error expression.
smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/syntax/rule/ErrorRule.java