Reject circular imports

2 files changed, 44 insertions, 25 deletions

diff --git a/boot/dependency.cc b/boot/dependency.cc
index 4590513..7f87e40 100644
--- a/boot/dependency.cc
+++ b/boot/dependency.cc
@@ -26,6 +26,17 @@ along with GCC; see the file COPYING3.  If not see
 
 namespace elna::boot
 {
+    circular_import_error::circular_import_error(const source_position position,
+            const std::string& module_name)
+        : diagnostic(position), module_name(module_name)
+    {
+    }
+
+    std::string circular_import_error::what() const
+    {
+        return "Circular import of module '" + this->module_name + "'";
+    }
+
     dependency read_source(std::istream& entry_point, const target_info& target)
     {
         driver parse_driver;
@@ -35,58 +46,66 @@ namespace elna::boot
         dependency outcome;
         if (parser() != 0)
         {
-            std::swap(outcome.errors(), parse_driver.errors());
+            std::swap(outcome.errors, parse_driver.errors());
             return outcome;
         }
         else
         {
-            std::swap(outcome.tree, parse_driver.tree);
+            std::swap(outcome.value, parse_driver.tree);
         }
         materialization_visitor materialization_visitor(target);
-        outcome.tree->accept(&materialization_visitor);
+        outcome.value->accept(&materialization_visitor);
 
         if (materialization_visitor.has_errors())
         {
-            std::swap(outcome.errors(), materialization_visitor.errors());
-            return outcome;
+            std::swap(outcome.errors, materialization_visitor.errors());
+            outcome.value.reset();
         }
-        declaration_visitor declaration_visitor{};
-        outcome.tree->accept(&declaration_visitor);
-
-        if (declaration_visitor.has_errors())
-        {
-            std::swap(outcome.errors(), declaration_visitor.errors());
-        }
-        outcome.unresolved = declaration_visitor.unresolved;
-
         return outcome;
     }
 
-    diagnostic_list analyze_semantics(std::unique_ptr<unit>& tree, symbol_bag& bag,
-            const target_info& target)
+    analysis_result analyze_semantics(std::unique_ptr<unit>& tree,
+            const std::vector<std::shared_ptr<symbol_table>>& imports,
+            const std::shared_ptr<symbol_table>& globals, const target_info& target)
     {
-        name_analysis_visitor name_analyser(bag, target);
+        declaration_visitor declarations{};
+        tree->accept(&declarations);
+        analysis_result result{ .value = { std::move(declarations.unresolved), globals }, .errors = {} };
+
+        if (declarations.has_errors())
+        {
+            std::swap(result.errors, declarations.errors());
+            return result;
+        }
+        for (const auto& import : imports)
+        {
+            result.value.add_import(import);
+        }
+        name_analysis_visitor name_analyser(result.value, target);
         tree->accept(&name_analyser);
 
         if (name_analyser.has_errors())
         {
-            return std::move(name_analyser.errors());
+            std::swap(result.errors, name_analyser.errors());
+            return result;
         }
-        type_analysis_visitor type_analyzer(bag, target);
+        type_analysis_visitor type_analyzer(result.value, target);
         tree->accept(&type_analyzer);
 
         if (type_analyzer.has_errors())
         {
-            return std::move(type_analyzer.errors());
+            std::swap(result.errors, type_analyzer.errors());
+            return result;
         }
-        validation_visitor validator(bag, target);
+        validation_visitor validator(result.value, target);
         tree->accept(&validator);
 
         if (validator.has_errors())
         {
-            return std::move(validator.errors());
+            std::swap(result.errors, validator.errors());
+            return result;
         }
-        return diagnostic_list{};
+        return result;
     }
 
     std::filesystem::path build_path(const std::vector<std::string>& segments)
diff --git a/boot/symbol.cc b/boot/symbol.cc
index b32782e..fcafae4 100644
--- a/boot/symbol.cc
+++ b/boot/symbol.cc
@@ -409,9 +409,9 @@ namespace elna::boot
         return unresolved_declaration;
     }
 
-    void symbol_bag::add_import(const symbol_bag& bag)
+    void symbol_bag::add_import(const std::shared_ptr<symbol_table>& symbols)
     {
-        this->imports.push_front(bag.exported_symbols());
+        this->imports.push_front(symbols);
     }
 
     bool symbol_bag::is_global() const