From b84e7c69ae52155c4902cf24b4f9bb86d65d5f9e Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Sun, 21 Sep 2025 18:46:28 -0400
Subject: Be more lenient with underscore fields and arguments.

---
 src/compile/functions.c |  3 ++-
 src/compile/structs.c   |  4 +++-
 src/typecheck.c         | 16 +---------------
 3 files changed, 6 insertions(+), 17 deletions(-)

(limited to 'src')

diff --git a/src/compile/functions.c b/src/compile/functions.c
index abe0a588..e3dbc2e7 100644
--- a/src/compile/functions.c
+++ b/src/compile/functions.c
@@ -155,7 +155,8 @@ Text_t compile_function_call(env_t *env, ast_t *ast) {
         if (!is_valid_call(env, Match(fn_t, FunctionType)->args, call->args, (call_opts_t){.promotion = true})) {
             if (is_valid_call(env, Match(fn_t, FunctionType)->args, call->args,
                               (call_opts_t){.promotion = true, .underscores = true})) {
-                code_err(ast, "You can't pass underscore arguments to this function (those are private)");
+                code_err(ast, "You can't pass underscore arguments to this function as positional arguments. You must "
+                              "use keyword arguments.");
             } else {
                 arg_t *args = NULL;
                 for (arg_ast_t *a = call->args; a; a = a->next)
diff --git a/src/compile/structs.c b/src/compile/structs.c
index aaebef22..2e7217f6 100644
--- a/src/compile/structs.c
+++ b/src/compile/structs.c
@@ -127,7 +127,9 @@ Text_t compile_struct_literal(env_t *env, ast_t *ast, type_t *t, arg_ast_t *args
         return Texts("((", compile_type(t), "){", compile_arguments(env, ast, struct_->fields, args), "})");
     } else if (!constructor_opts.underscores
                && is_valid_call(env, struct_->fields, args, (call_opts_t){.promotion = true, .underscores = true})) {
-        code_err(ast, "This constructor uses private fields that are not exposed.");
+        code_err(ast, "This constructor is passing private fields (those starting with underscores) as positional "
+                      "arguments, which is not allowed. \n"
+                      " If you need to pass these fields, use a keyword argument.");
     }
     code_err(ast, "I could not find a constructor matching these arguments for the struct ", type_to_text(t));
 }
diff --git a/src/typecheck.c b/src/typecheck.c
index 9d33e119..6cd87289 100644
--- a/src/typecheck.c
+++ b/src/typecheck.c
@@ -905,16 +905,6 @@ type_t *get_type(env_t *env, ast_t *ast) {
     case FieldAccess: {
         DeclareMatch(access, ast, FieldAccess);
         type_t *fielded_t = get_type(env, access->fielded);
-        if (access->field[0] == '_') {
-            if (!env->current_type
-                || !type_eq(env->current_type, fielded_t->tag == TypeInfoType ? Match(fielded_t, TypeInfoType)->type
-                                                                              : value_type(fielded_t)))
-                code_err(ast, "Fields beginning with underscores like '", access->field,
-                         "' can't be accessed outside the scope where the type (",
-                         type_to_text(fielded_t->tag == TypeInfoType ? Match(fielded_t, TypeInfoType)->type
-                                                                     : value_type(fielded_t)),
-                         ") is defined.");
-        }
         if (fielded_t->tag == ModuleType) {
             const char *name = Match(fielded_t, ModuleType)->name;
             env_t *module_env = Table$str_get(*env->imports, name);
@@ -1049,9 +1039,7 @@ type_t *get_type(env_t *env, ast_t *ast) {
             if (call->name[0] == '_') {
                 if (env->current_type == NULL || !type_eq(env->current_type, self_value_t))
                     code_err(ast, "You can't call private methods starting with underscore (like '", call->name,
-                             "') "
-                             "outside of the place where the type (",
-                             type_to_text(self_value_t), ") is defined.");
+                             "') outside of the place where the type (", type_to_text(self_value_t), ") is defined.");
             }
             type_t *field_type = get_field_type(self_value_t, call->name);
             if (field_type && field_type->tag == ClosureType) field_type = Match(field_type, ClosureType)->fn;
@@ -1625,10 +1613,8 @@ bool is_valid_call(env_t *env, arg_t *spec_args, arg_ast_t *call_args, call_opts
     // Populate keyword args:
     for (arg_ast_t *call_arg = call_args; call_arg; call_arg = call_arg->next) {
         if (!call_arg->name) continue;
-        if (!options.underscores && call_arg->name[0] == '_') return false;
 
         for (arg_t *spec_arg = spec_args; spec_arg; spec_arg = spec_arg->next) {
-            if (!options.underscores && spec_arg->name[0] == '_') continue;
             if (!(streq(call_arg->name, spec_arg->name) || (spec_arg->alias && streq(call_arg->name, spec_arg->alias))))
                 continue;
             type_t *spec_type = get_arg_type(env, spec_arg);
-- 
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