add hashCode to primitives

src/main/java/me/topchetoeu/jscript/runtime/values/primitives/BoolValue.java

@@ -20,6 +20,9 @@ public final class BoolValue extends PrimitiveValue {
         return env.get(BOOL_PROTO);
     }
 
+	@Override public int hashCode() {
+		return Boolean.hashCode(value);
+	}
     @Override public boolean equals(Object other) {
         if (other == this) return true;
         else if (other instanceof BoolValue bool) return value == bool.value;

src/main/java/me/topchetoeu/jscript/runtime/values/primitives/StringValue.java

@@ -36,6 +36,9 @@ public final class StringValue extends PrimitiveValue {
     }
     @Override public String toString(Environment ext) { return value; }
 
+	@Override public int hashCode() {
+		return value.hashCode();
+	}
     @Override public boolean equals(Object other) {
         if (this == other) return true;
         else if (other instanceof StringValue val) return value.length() == val.value.length() && value.equals(val.value);

src/main/java/me/topchetoeu/jscript/runtime/values/primitives/VoidValue.java

@@ -23,7 +23,8 @@ public final class VoidValue extends PrimitiveValue {
     @Override public ObjectValue getPrototype(Environment env) { return null; }
 
     @Override public Member getOwnMember(Environment env, KeyCache key) {
-        throw EngineException.ofError(String.format("Cannot read properties of %s (reading '%s')", name, key.toString(env)));
+		if (key.isSymbol()) throw EngineException.ofError(String.format("Cannot read properties of %s (reading '%s')", name, key.toSymbol().toString()));
+		else throw EngineException.ofError(String.format("Cannot read properties of %s (reading '%s')", name, key.toString(env)));
     }
 
     @Override public List<String> toReadableLines(Environment env, HashSet<ObjectValue> passed) {

src/main/java/me/topchetoeu/jscript/runtime/values/primitives/numbers/DoubleValue.java

@@ -24,6 +24,9 @@ public final class DoubleValue extends NumberValue {
 
     @Override public String toString() { return JSON.stringify(JSONElement.number(value)); }
 
+	@Override public int hashCode() {
+		return Double.hashCode(value);
+	}
     @Override public boolean equals(Object other) {
         if (this == other) return true;
         else if (other instanceof NumberValue val) return value == val.getDouble();

src/main/java/me/topchetoeu/jscript/runtime/values/primitives/numbers/IntValue.java

@@ -26,6 +26,9 @@ public final class IntValue extends NumberValue {
         return value;
     }
 
+	@Override public int hashCode() {
+		return Long.hashCode(value);
+	}
     @Override public String toString() { return value + ""; }
     @Override public boolean equals(Object other) {
         if (this == other) return true;