From 5cdaceb77af6a1d98145f8afb34ce6884e21a3d6 Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Sun, 26 Jul 2026 19:47:59 +0200
Subject:  Type check traits properly

---
 boot/type_check.cc | 68 ++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 48 insertions(+), 20 deletions(-)

(limited to 'boot/type_check.cc')

diff --git a/boot/type_check.cc b/boot/type_check.cc
index c88a7d1..2bb0ddd 100644
--- a/boot/type_check.cc
+++ b/boot/type_check.cc
@@ -22,14 +22,30 @@ along with GCC; see the file COPYING3.  If not see
 
 namespace elna::boot
 {
-    non_constant_initializer_error::non_constant_initializer_error(const source_position position)
-        : error(position)
+    trait_error::trait_error(const source_position position, const std::string& trait_name,
+            payload_type payload)
+        : error(position), trait_name(trait_name), m_payload(payload)
     {
     }
 
-    std::string non_constant_initializer_error::what() const
+    std::string trait_error::what() const
     {
-        return "Variable initializers must be constant expressions";
+        return std::visit([this](auto&& payload) -> std::string
+        {
+            using T = std::decay_t<decltype(payload)>;
+
+            if constexpr (std::is_same_v<T, argument_count>)
+            {
+                return "Trait #" + this->trait_name + " expects "
+                        + std::to_string(payload.expected) + " argument"
+                        + (payload.expected != 1 ? "s" : "") + ", got "
+                        + std::to_string(payload.actual);
+            }
+            else
+            {
+                return "The second argument to the #" + this->trait_name + " trait must be a field name";
+            }
+        }, this->m_payload);
     }
 
     type_mismatch_error::type_mismatch_error(const source_position position,
@@ -453,22 +469,6 @@ namespace elna::boot
         {
             return;
         }
-        evaluator constant_evaluator(this->bag, this->target, this->evaluated_initializers);
-        if (!constant_evaluator.evaluate(*declaration->initializer))
-        {
-            add_error<non_constant_initializer_error>(declaration->initializer->position());
-            return;
-        }
-        // Record const variable initializers so later declarations
-        // can chain through them.
-        for (const auto& identifier : declaration->identifiers)
-        {
-            if (auto var = this->bag.lookup(identifier.name())->is_variable();
-                    resolve_aliases(var->symbol).get<constant_type>() != nullptr)
-            {
-                this->evaluated_initializers[identifier.name()] = declaration->initializer;
-            }
-        }
         for (const identifier_definition& variable_identifier : declaration->identifiers)
         {
             auto variable_symbol = this->bag.lookup(variable_identifier.name())->is_variable();
@@ -864,4 +864,32 @@ namespace elna::boot
                     expression->lhs().type_decoration, expression->rhs().type_decoration, operation);
         }
     }
+
+    void type_analysis_visitor::visit(traits_expression *trait)
+    {
+        walking_visitor::visit(trait);
+
+        if (trait->name == "size" || trait->name == "alignment"
+                || trait->name == "min" || trait->name == "max")
+        {
+            if (trait->arguments.size() != 1)
+            {
+                add_error<trait_error>(trait->position(), trait->name.name(),
+                        trait_error::argument_count{ .expected = 1, .actual = trait->arguments.size() });
+            }
+        }
+        else if (trait->name == "offset")
+        {
+            if (trait->arguments.size() != 2)
+            {
+                add_error<trait_error>(trait->position(), trait->name.name(),
+                        trait_error::argument_count{ .expected = 2, .actual = trait->arguments.size() });
+            }
+            else if (trait->arguments.at(1)->is_named() == nullptr)
+            {
+                add_error<trait_error>(trait->arguments.at(1)->position(), trait->name.name(),
+                        trait_error::offset_not_field_name{});
+            }
+        }
+    }
 }
-- 
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