1 files changed, 17 insertions, 2 deletions

diff --git a/src/ast.c b/src/ast.c
index 90af981..5336e1e 100644
--- a/src/ast.c
+++ b/src/ast.c
@@ -733,8 +733,17 @@ static usize min(usize a, usize b) {
     return a < b ? a : b;
 }
 
+static bool is_c_pointer_compatible(VariableType *self) {
+    return self->variable_type_flags & (VARIABLE_TYPE_FLAG_OPTIONAL | VARIABLE_TYPE_FLAG_BORROW);
+}
+
+static bool is_type_compatible_with(AstResolvedType *self, AstResolvedType *other, AstCompilerContext *context) {
+    return self->value.data == &context->compiler->default_types.str->lhs_expr &&
+        other->value.data == context->compiler->default_types.c_char && is_c_pointer_compatible(&other->value.lhs_expr->type);
+}
+
 static bool resolve_data_type_equals(AstResolvedType *self, AstResolvedType *other) {
-    return self->type == other->type && self->value.data == other->value.data;
+    return self->value.data == other->value.data;
 }
 
 static bool function_parameter_is_vararg(FunctionParameter *self, AstCompilerContext *context) {
@@ -742,6 +751,12 @@ static bool function_parameter_is_vararg(FunctionParameter *self, AstCompilerCon
     return self->resolve_data.type.value.data == &vararg_type->lhs_expr;
 }
 
+static bool is_function_arg_compatible_with_parameter(AstResolvedType *arg, FunctionParameter *param, AstCompilerContext *context) {
+    return resolve_data_type_equals(arg, &param->resolve_data.type) ||
+           is_type_compatible_with(arg, &param->resolve_data.type, context) ||
+           function_parameter_is_vararg(param, context);
+}
+
 static void verify_func_call_matches_func_signature(FunctionCall *func_call, FunctionSignature *func_sig, AstCompilerContext *context) {
     Ast **arg = buffer_begin(&func_call->args);
     Ast **arg_end = buffer_end(&func_call->args);
@@ -755,7 +770,7 @@ static void verify_func_call_matches_func_signature(FunctionCall *func_call, Fun
     usize num_check = min(num_args, num_params);
     usize i = 0;
     for(; i < num_check; ++i) {
-        if(!resolve_data_type_equals(&(*arg)->resolve_data.type, &func_param->resolve_data.type) && !function_parameter_is_vararg(func_param, context)) {
+        if(!is_function_arg_compatible_with_parameter(&(*arg)->resolve_data.type, func_param, context)) {
             BufferView arg_name = ast_resolved_type_get_name(&(*arg)->resolve_data.type);
             BufferView param_name = ast_resolved_type_get_name(&func_param->resolve_data.type);
             compiler_print_error(context->compiler, func_call->func.name.data,