Reimplement context validation on parse by struct

Author: ksss

ext/rbs_extension/main.c

@@ -7,6 +7,7 @@
 #include "rbs_string_bridging.h"
 
 #include "ruby/vm.h"
+#include "rbs/parser.h"
 
 /**
  * Raises `RBS::ParsingError` or `RuntimeError` on `tok` with message constructed with given `fmt`.
@@ -101,7 +102,7 @@ static VALUE parse_type_try(VALUE a) {
     }
 
     rbs_node_t *type;
-    rbs_parse_type(parser, &type);
+    rbs_parse_type(parser, &type, SkipValidation);
 
     raise_error_if_any(parser, arg->buffer);
 
@@ -187,7 +188,7 @@ static VALUE parse_method_type_try(VALUE a) {
     }
 
     rbs_method_type_t *method_type = NULL;
-    rbs_parse_method_type(parser, &method_type);
+    rbs_parse_method_type(parser, &method_type, SkipValidation);
 
     raise_error_if_any(parser, arg->buffer);
 

include/rbs/parser.h

@@ -126,8 +126,24 @@ rbs_ast_comment_t *rbs_parser_get_comment(rbs_parser_t *parser, int subject_line
 
 void rbs_parser_set_error(rbs_parser_t *parser, rbs_token_t tok, bool syntax_error, const char *fmt, ...) RBS_ATTRIBUTE_FORMAT(4, 5);
 
-bool rbs_parse_type(rbs_parser_t *parser, rbs_node_t **type);
-bool rbs_parse_method_type(rbs_parser_t *parser, rbs_method_type_t **method_type);
+/**
+ * TypeValidation represents the validation rules for type parsing.
+ * It controls whether certain types are allowed in specific contexts.
+ * */
+typedef struct {
+    bool no_void;              /* If true, `void` type is not allowed.*/
+    bool no_void_allowed_here; /* If true, `void` type is not allowed, but it's allowed in one depth.*/
+    bool no_self;              /* If true, `self` type is not allowed.*/
+    bool no_classish;          /* If true, `class` or `instance` types are not allowed.*/
+} TypeValidation;
+
+/**
+ * SkipValidation is a TypeValidation that allows all types.
+ * */
+extern const TypeValidation SkipValidation;
+
+bool rbs_parse_type(rbs_parser_t *parser, rbs_node_t **type, TypeValidation validation);
+bool rbs_parse_method_type(rbs_parser_t *parser, rbs_method_type_t **method_type, TypeValidation validation);
 bool rbs_parse_signature(rbs_parser_t *parser, rbs_signature_t **signature);
 
 bool rbs_parse_type_params(rbs_parser_t *parser, bool module_type_params, rbs_node_list_t **params);