Build the class layout for the instantiated symbols

src/parser/cxx/name_lookup.cc

@@ -53,15 +53,40 @@ auto Lookup::qualifiedLookup(Symbol* scopedSymbol, const Name* name) const
     case SymbolKind::kNamespace:
       return qualifiedLookup(
           symbol_cast<NamespaceSymbol>(scopedSymbol)->scope(), name);
+
     case SymbolKind::kClass:
       return qualifiedLookup(symbol_cast<ClassSymbol>(scopedSymbol)->scope(),
                              name);
+
     case SymbolKind::kEnum:
       return qualifiedLookup(symbol_cast<EnumSymbol>(scopedSymbol)->scope(),
                              name);
+
     case SymbolKind::kScopedEnum:
       return qualifiedLookup(
           symbol_cast<ScopedEnumSymbol>(scopedSymbol)->scope(), name);
+
+    case SymbolKind::kTypeAlias: {
+      auto alias = symbol_cast<TypeAliasSymbol>(scopedSymbol);
+
+      if (auto classType = type_cast<ClassType>(alias->type())) {
+        auto classSymbol = classType->symbol();
+        return qualifiedLookup(classSymbol->scope(), name);
+      }
+
+      if (auto enumType = type_cast<EnumType>(alias->type())) {
+        auto enumSymbol = enumType->symbol();
+        return qualifiedLookup(enumSymbol->scope(), name);
+      }
+
+      if (auto scopedEnumType = type_cast<ScopedEnumType>(alias->type())) {
+        auto scopedEnumSymbol = scopedEnumType->symbol();
+        return qualifiedLookup(scopedEnumSymbol->scope(), name);
+      }
+
+      return nullptr;
+    }
+
     default:
       return nullptr;
   }  // switch

src/parser/cxx/parser.cc

@@ -5272,29 +5272,33 @@ auto Parser::parse_static_assert_declaration(DeclarationAST*& yyast) -> bool {
 
   expect(TokenKind::T_SEMICOLON, ast->semicolonLoc);
 
-  bool value = false;
+  if (!inTemplate_) {
+    // not in a template context
 
-  if (constValue.has_value()) {
-    value = visit(to_bool, *constValue);
-  }
+    bool value = false;
 
-  if (!value && config_.staticAssert) {
-    SourceLocation loc = ast->firstSourceLocation();
+    if (constValue.has_value()) {
+      value = visit(to_bool, *constValue);
+    }
 
-    if (!ast->expression || !constValue.has_value()) {
-      parse_error(
-          loc,
-          "static assertion expression is not an integral constant expression");
-    } else {
-      if (ast->literalLoc)
-        loc = ast->literalLoc;
-      else if (ast->expression)
-        ast->expression->firstSourceLocation();
+    if (!value && config_.staticAssert) {
+      SourceLocation loc = ast->firstSourceLocation();
+
+      if (!ast->expression || !constValue.has_value()) {
+        parse_error(loc,
+                    "static assertion expression is not an integral constant "
+                    "expression");
+      } else {
+        if (ast->literalLoc)
+          loc = ast->literalLoc;
+        else if (ast->expression)
+          ast->expression->firstSourceLocation();
 
-      std::string message =
-          ast->literal ? ast->literal->value() : "static assert failed";
+        std::string message =
+            ast->literal ? ast->literal->value() : "static assert failed";
 
-      unit->error(loc, std::move(message));
+        unit->error(loc, std::move(message));
+      }
     }
   }
 
@@ -9431,66 +9435,11 @@ auto Parser::parse_class_specifier(
     expect(TokenKind::T_RBRACE, ast->rbraceLoc);
   }
 
-  if (!is_template(classSymbol)) {
-    int offset = 0;
-    int alignment = 1;
-
-    for (auto base : classSymbol->baseClasses()) {
-      auto baseClassSymbol = symbol_cast<ClassSymbol>(base->symbol());
-
-      if (!baseClassSymbol) {
-        if (config_.checkTypes) {
-          parse_error(base->location(), std::format("base class '{}' not found",
-                                                    to_string(base->name())));
-        }
-        continue;
-      }
-
-      offset = align_to(offset, baseClassSymbol->alignment());
-      offset += baseClassSymbol->sizeInBytes();
-      alignment = std::max(alignment, baseClassSymbol->alignment());
-    }
-
-    for (auto member : classSymbol->scope()->symbols()) {
-      auto field = symbol_cast<FieldSymbol>(member);
-      if (!field) continue;
-      if (field->isStatic()) continue;
-
-      if (!field->alignment()) {
-        if (config_.checkTypes) {
-          parse_error(field->location(),
-                      std::format("alignment of incomplete type '{}'",
-                                  to_string(field->type(), field->name())));
-        }
-        continue;
-      }
-
-      auto size = control_->memoryLayout()->sizeOf(field->type());
-
-      if (!size.has_value()) {
-        if (config_.checkTypes) {
-          parse_error(field->location(),
-                      std::format("size of incomplete type '{}'",
-                                  to_string(field->type(), field->name())));
-        }
-        continue;
-      }
-
-      if (classSymbol->isUnion()) {
-        offset = std::max(offset, int(size.value()));
-      } else {
-        offset = align_to(offset, field->alignment());
-        field->setOffset(offset);
-        offset += size.value();
-      }
-
-      alignment = std::max(alignment, field->alignment());
+  if (!inTemplate_) {
+    auto status = classSymbol->buildClassLayout(control_);
+    if (!status.has_value() && config_.checkTypes) {
+      parse_error(classSymbol->location(), status.error());
     }
-
-    offset = align_to(offset, alignment);
-
-    classSymbol->setAlignment(alignment);
-    classSymbol->setSizeInBytes(offset);
   }
 
   classSymbol->setComplete(true);
@@ -11506,7 +11455,18 @@ void Parser::completePendingFunctionDefinitions() {
   }
 }
 
-void Parser::setScope(Scope* scope) { scope_ = scope; }
+void Parser::setScope(Scope* scope) {
+  scope_ = scope;
+
+  inTemplate_ = false;
+
+  for (auto current = scope_; current; current = current->parent()) {
+    if (current->isTemplateParametersScope()) {
+      inTemplate_ = true;
+      break;
+    }
+  }
+}
 
 void Parser::setScope(ScopedSymbol* symbol) { setScope(symbol->scope()); }
 

src/parser/cxx/parser.h

@@ -911,6 +911,7 @@ class Parser final {
   int templateParameterCount_ = 0;
   bool didAcceptCompletionToken_ = false;
   std::vector<FunctionDefinitionAST*> pendingFunctionDefinitions_;
+  bool inTemplate_ = false;
 
   template <typename T>
   class CachedAST {

src/parser/cxx/symbol_instantiation.cc

@@ -23,9 +23,12 @@
 // cxx
 #include <cxx/ast.h>
 #include <cxx/control.h>
+#include <cxx/memory_layout.h>
+#include <cxx/name_printer.h>
 #include <cxx/scope.h>
 #include <cxx/symbols.h>
 #include <cxx/translation_unit.h>
+#include <cxx/type_printer.h>
 #include <cxx/types.h>
 
 #include <format>
@@ -185,9 +188,19 @@ auto SymbolInstantiation::findOrCreateReplacement(Symbol* symbol) -> Symbol* {
   replacements_[symbol] = newSymbol;
 
   auto enclosingSymbol = replacement(symbol->enclosingSymbol());
+
   newSymbol->setEnclosingScope(enclosingSymbol->scope());
+
   if (symbol->type()) {
     newSymbol->setType(visit(VisitType{*this}, symbol->type()));
+
+    auto field = symbol_cast<FieldSymbol>(newSymbol);
+
+    if (field) {
+      auto memoryLayout = control()->memoryLayout();
+      auto alignment = memoryLayout->alignmentOf(newSymbol->type());
+      field->setAlignment(alignment.value_or(0));
+    }
   }
 
   newSymbol->setName(symbol->name());
@@ -217,6 +230,10 @@ auto SymbolInstantiation::VisitSymbol::operator()(ClassSymbol* symbol)
   auto newSymbol = self.replacement(symbol);
   newSymbol->setFlags(symbol->flags());
 
+  if (symbol->isComplete()) {
+    newSymbol->setComplete(true);
+  }
+
   if (symbol != self.current_) {
     newSymbol->setTemplateParameters(
         self.instantiate(symbol->templateParameters()));
@@ -226,14 +243,19 @@ auto SymbolInstantiation::VisitSymbol::operator()(ClassSymbol* symbol)
     auto newBaseClass = self.instantiate(baseClass);
     newSymbol->addBaseClass(newBaseClass);
   }
+
   for (auto ctor : symbol->constructors()) {
     auto newCtor = self.instantiate(ctor);
     newSymbol->addConstructor(newCtor);
   }
+
   for (auto member : views::members(symbol)) {
     auto newMember = self.instantiate(member);
     newSymbol->addMember(newMember);
   }
+
+  auto status = newSymbol->buildClassLayout(self.control());
+
   return newSymbol;
 }
 

src/parser/cxx/symbols.cc

@@ -22,8 +22,15 @@
 
 // cxx
 #include <cxx/ast.h>
+#include <cxx/control.h>
+#include <cxx/memory_layout.h>
+#include <cxx/name_printer.h>
 #include <cxx/scope.h>
+#include <cxx/type_printer.h>
 #include <cxx/types.h>
+#include <cxx/util.h>
+
+#include <format>
 
 namespace cxx {
 
@@ -184,7 +191,7 @@ void ClassSymbol::setSizeInBytes(int sizeInBytes) {
   sizeInBytes_ = sizeInBytes;
 }
 
-auto ClassSymbol::alignment() const -> int { return alignment_; }
+auto ClassSymbol::alignment() const -> int { return std::max(alignment_, 1); }
 
 void ClassSymbol::setAlignment(int alignment) { alignment_ = alignment; }
 
@@ -241,6 +248,64 @@ void ClassSymbol::addSpecialization(std::vector<TemplateArgument> arguments,
   templateInfo_->addSpecialization(std::move(arguments), specialization);
 }
 
+auto ClassSymbol::buildClassLayout(Control* control)
+    -> std::expected<bool, std::string> {
+  int offset = 0;
+  int alignment = 1;
+
+  auto memoryLayout = control->memoryLayout();
+
+  for (auto base : baseClasses()) {
+    auto baseClassSymbol = symbol_cast<ClassSymbol>(base->symbol());
+
+    if (!baseClassSymbol) {
+      return std::unexpected(
+          std::format("base class '{}' not found", to_string(base->name())));
+    }
+
+    offset = align_to(offset, baseClassSymbol->alignment());
+    offset += baseClassSymbol->sizeInBytes();
+    alignment = std::max(alignment, baseClassSymbol->alignment());
+  }
+
+  for (auto member : scope()->symbols()) {
+    auto field = symbol_cast<FieldSymbol>(member);
+    if (!field) continue;
+    if (field->isStatic()) continue;
+
+    if (!field->alignment()) {
+      return std::unexpected(
+          std::format("alignment of incomplete type '{}'",
+                      to_string(field->type(), field->name())));
+    }
+
+    auto size = memoryLayout->sizeOf(field->type());
+
+    if (!size.has_value()) {
+      return std::unexpected(
+          std::format("size of incomplete type '{}'",
+                      to_string(field->type(), field->name())));
+    }
+
+    if (isUnion()) {
+      offset = std::max(offset, int(size.value()));
+    } else {
+      offset = align_to(offset, field->alignment());
+      field->setOffset(offset);
+      offset += size.value();
+    }
+
+    alignment = std::max(alignment, field->alignment());
+  }
+
+  offset = align_to(offset, alignment);
+
+  setAlignment(alignment);
+  setSizeInBytes(offset);
+
+  return true;
+}
+
 EnumSymbol::EnumSymbol(Scope* enclosingScope)
     : ScopedSymbol(Kind, enclosingScope) {}
 

src/parser/cxx/symbols.h

@@ -27,6 +27,7 @@
 #include <cxx/symbols_fwd.h>
 #include <cxx/types_fwd.h>
 
+#include <expected>
 #include <memory>
 #include <optional>
 #include <ranges>
@@ -298,6 +299,9 @@ class ClassSymbol final : public ScopedSymbol {
     return templateSepcializationIndex_;
   }
 
+  [[nodiscard]] auto buildClassLayout(Control* control)
+      -> std::expected<bool, std::string>;
+
  private:
   [[nodiscard]] auto hasBaseClass(Symbol* symbol,
                                   std::unordered_set<const ClassSymbol*>&) const

tests/unit_tests/sema/template_class_04.cc

@@ -0,0 +1,28 @@
+// RUN: %cxx -verify -ftemplates -fcheck %s
+
+template <typename Key, typename Value>
+struct X {
+  Key key;
+  Value value;
+
+  void check() { static_assert(sizeof(*this)); }
+};
+
+auto main() -> int {
+  using U = X<char, int>;
+  U u;
+
+  static_assert(sizeof(U) == 8);
+  static_assert(sizeof(u) == 8);
+
+  static_assert(__builtin_offsetof(U, key) == 0);
+  static_assert(__builtin_offsetof(U, value) == 4);
+
+  static_assert(sizeof(X<char, int>::key) == 1);
+  static_assert(sizeof(X<char, int>::value) == 4);
+
+  static_assert(sizeof(U::key) == 1);
+  static_assert(sizeof(U::value) == 4);
+
+  return 0;
+}