### Godot version

Beta 17, master

### System information

Windows 11

### Issue description

Godot gets a hard crash while attempting to code-complete for member `const` of a class.

### Steps to reproduce

```GDScript
enum E { V1 }

const e := E
```

And then type a `.` after the last `E`, which triggers code hints/auto-completion for subscripts based on `E` and causes a hard crash.

Does not happen for `var e := E.V1`.

### Minimal reproduction project

See above.
for (int i = 0; i < p_match_branch->patterns.size(); i++) {
		resolve_match_pattern(p_match_branch->patterns[i], p_match_test);
	}
	resolve_suite(p_match_branch->block);
	decide_suite_type(p_match_branch, p_match_branch->block);
}
void GDScriptAnalyzer::resolve_match_pattern(GDScriptParser::PatternNode *p_match_pattern, GDScriptParser::ExpressionNode *p_match_test) {
	if (p_match_pattern == nullptr) {
		return;
	}
	GDScriptParser::DataType result;
	switch (p_match_pattern->pattern_type) {
		case GDScriptParser::PatternNode::PT_LITERAL:
			if (p_match_pattern->literal) {
				reduce_literal(p_match_pattern->literal);
				result = p_match_pattern->literal->get_datatype();
			}
			break;
		case GDScriptParser::PatternNode::PT_EXPRESSION:
			if (p_match_pattern->expression) {
				GDScriptParser::ExpressionNode *expr = p_match_pattern->expression;
				reduce_expression(expr);
				result = expr->get_datatype();
				if (!expr->is_constant) {
					while (expr && expr->type == GDScriptParser::Node::SUBSCRIPT) {
						GDScriptParser::SubscriptNode *sub = static_cast<GDScriptParser::SubscriptNode *>(expr);