Function formatTypeParams

parse/getast.go:233–255

formatTypeParams converts an AST FieldList to a string representation

(params *ast.FieldList)

// formatTypeParams converts an AST FieldList to a string representation
func formatTypeParams(params *ast.FieldList) string {
	if params == nil || params.NumFields() == 0 {
		return ""
	}

	var paramStrs []string
	for _, field := range params.List {
		// Convert underscores to _RTn where n is the number of the parameter
		convert := isrtfor(field.Type)

		// Each field can have multiple names (e.g., T, U constraint)
		for _, name := range field.Names {
			if convert && name.Name == "_" {
				name.Name = fmt.Sprintf("_RT%d", len(paramStrs)+1)
			}
			// For method receivers, we only include the type parameter name
			// The constraints are defined in the type declaration, not the method receiver
			paramStrs = append(paramStrs, name.Name)
		}
	}

	return "[" + strings.Join(paramStrs, ", ") + "]"
}

// isrtfor returns whether the provided expression is a msgp.RTFor[T] pattern.
func isrtfor(t ast.Expr) bool { return strings.HasPrefix(stringify(t), "msgp.RTFor[") }