Fix missing syntax highlights for structs.

modules/gdscript/editor/gdscript_highlighter.cpp

@@ -480,6 +480,10 @@ Dictionary GDScriptSyntaxHighlighter::_get_line_syntax_highlighting_impl(int p_l
 					}
 				} else if (prev_text == GDScriptTokenizer::get_token_name(GDScriptTokenizer::Token::VAR) || prev_text == GDScriptTokenizer::get_token_name(GDScriptTokenizer::Token::FOR) || prev_text == GDScriptTokenizer::get_token_name(GDScriptTokenizer::Token::TK_CONST)) {
 					in_var_const_declaration = true;
+					// A `var` field inside a struct body reads as a member variable.
+					if (prev_text == GDScriptTokenizer::get_token_name(GDScriptTokenizer::Token::VAR) && struct_body_lines.has(p_line)) {
+						in_member_variable = true;
+					}
 				}
 
 				// Check for lambda.
@@ -746,6 +750,18 @@ void GDScriptSyntaxHighlighter::_update_cache() {
 		class_names[class_name] = usertype_color;
 	}
 
+	// Global structs (declared with `struct_name`).
+	List<StringName> global_structs;
+	ScriptServer::get_global_struct_list(&global_structs);
+	for (const StringName &struct_name : global_structs) {
+		class_names[struct_name] = usertype_color;
+	}
+
+	// Local structs declared in the edited script (not registered globally).
+	for (const StringName &struct_name : _get_local_struct_names()) {
+		class_names[struct_name] = usertype_color;
+	}
+
 	/* Autoloads. */
 	for (const KeyValue<StringName, ProjectSettings::AutoloadInfo> &E : ProjectSettings::get_singleton()->get_autoload_list()) {
 		const ProjectSettings::AutoloadInfo &info = E.value;
@@ -935,6 +951,70 @@ void GDScriptSyntaxHighlighter::_update_cache() {
 	}
 }
 
+LocalVector<StringName> GDScriptSyntaxHighlighter::_get_local_struct_names() {
+	// Structs are declared at file scope with `struct Name:` or `struct_name Name:`.
+	// They aren't exposed on the compiled script, so scan the source for their names
+	// to highlight the type name at its declaration and at every use. Also record the
+	// lines that make up each struct body so their `var` fields read as members.
+	LocalVector<StringName> names;
+	struct_body_lines.clear();
+	if (text_edit == nullptr) {
+		return names;
+	}
+	const int line_count = text_edit->get_line_count();
+	int struct_indent = -1; // Indentation of the enclosing struct header, or -1 when outside a struct.
+	for (int i = 0; i < line_count; i++) {
+		const String raw = text_edit->get_line(i);
+		int indent = 0;
+		while (indent < raw.length() && is_whitespace(raw[indent])) {
+			indent++;
+		}
+		const String line = raw.substr(indent).strip_edges();
+
+		if (line.is_empty() || line.begins_with("#")) {
+			// Blank and comment lines don't end a struct body.
+			if (struct_indent >= 0) {
+				struct_body_lines.insert(i);
+			}
+			continue;
+		}
+
+		if (struct_indent >= 0) {
+			if (indent > struct_indent) {
+				struct_body_lines.insert(i);
+				continue;
+			}
+			struct_indent = -1; // Dedent closes the struct body.
+		}
+
+		String keyword;
+		if (line.begins_with("struct_name")) {
+			keyword = "struct_name";
+		} else if (line.begins_with("struct")) {
+			keyword = "struct";
+		} else {
+			continue;
+		}
+		int pos = keyword.length();
+		if (pos >= line.length() || !is_whitespace(line[pos])) {
+			continue; // Part of a longer identifier, not the keyword.
+		}
+		while (pos < line.length() && is_whitespace(line[pos])) {
+			pos++;
+		}
+		const int start = pos;
+		if (pos < line.length() && is_unicode_identifier_start(line[pos])) {
+			pos++;
+			while (pos < line.length() && is_unicode_identifier_continue(line[pos])) {
+				pos++;
+			}
+			names.push_back(line.substr(start, pos - start));
+			struct_indent = indent;
+		}
+	}
+	return names;
+}
+
 void GDScriptSyntaxHighlighter::add_color_region(ColorRegion::Type p_type, const String &p_start_key, const String &p_end_key, const Color &p_color, bool p_line_only, bool p_r_prefix) {
 	ERR_FAIL_COND_MSG(p_start_key.is_empty(), "Color region start key cannot be empty.");
 	ERR_FAIL_COND_MSG(!is_symbol(p_start_key[0]), "Color region start key must start with a symbol.");

modules/gdscript/editor/gdscript_highlighter.h

@@ -69,6 +69,7 @@ class GDScriptSyntaxHighlighter : public EditorSyntaxHighlighter {
 	HashMap<StringName, Color> reserved_keywords;
 	HashMap<StringName, Color> member_keywords;
 	HashSet<StringName> global_functions;
+	HashSet<int> struct_body_lines; ///< Lines inside a local struct body, for member-coloring its fields.
 
 	enum Type {
 		NONE,
@@ -116,6 +117,8 @@ class GDScriptSyntaxHighlighter : public EditorSyntaxHighlighter {
 
 	void add_color_region(ColorRegion::Type p_type, const String &p_start_key, const String &p_end_key, const Color &p_color, bool p_line_only = false, bool p_r_prefix = false);
 
+	LocalVector<StringName> _get_local_struct_names();
+
 public:
 	virtual void _update_cache() override;
 	virtual Dictionary _get_line_syntax_highlighting_impl(int p_line) override;