@Override
		public int hashCode() {
			int hashCode = 1;
			hashCode = 31 * hashCode + precedence;
			return hashCode;
		}
The default {@link SemanticContext}, which is semantically equivalent to
a predicate of the form {@code {true}?}.
runtime/Java/src/org/antlr/v4/runtime/atn/SemanticContext.java