Lookup of fields in anonymous nested structs and unions

Fixes #591

Signed-off-by: Roberto Raggi <[email protected]>

Author: robertoraggi

src/parser/cxx/name_lookup.cc

@@ -144,6 +144,19 @@ auto Lookup::lookupHelper(Scope* scope, const Name* name,
   }
 
   if (auto classSymbol = symbol_cast<ClassSymbol>(scope->owner())) {
+    // iterate over the annonymous nested structs and unions
+    for (auto member : classSymbol->scope()->symbols()) {
+      if (member->name()) continue;      // skip named members
+      if (!member->isClass()) continue;  // skip non-class members
+      auto nestedClass = symbol_cast<ClassSymbol>(member);
+      auto symbol = lookupHelper(nestedClass->scope(), name, cache, accept);
+
+      if (symbol) {
+        // found a match in an anonymous nested class
+        return symbol;
+      }
+    }
+
     for (const auto& base : classSymbol->baseClasses()) {
       auto baseClass = symbol_cast<ClassSymbol>(base->symbol());
       if (!baseClass) continue;

src/parser/cxx/parser.cc

@@ -7749,12 +7749,6 @@ auto Parser::parse_class_specifier(ClassSpecifierAST*& yyast, DeclSpecs& specs)
   SourceLocation classLoc;
   if (!parse_class_key(classLoc)) return false;
 
-  auto globalScopeGuard = Binder::ScopeGuard{&binder_};
-
-  if (is_parsing_c()) {
-    setScope(getCurrentNonClassScope());
-  }
-
   List<AttributeSpecifierAST*>* attributeList = nullptr;
   NestedNameSpecifierAST* nestedNameSpecifier = nullptr;
   UnqualifiedIdAST* unqualifiedId = nullptr;
@@ -7809,6 +7803,15 @@ auto Parser::parse_class_specifier(ClassSpecifierAST*& yyast, DeclSpecs& specs)
 
   if (!lookat_class_head()) return false;
 
+  auto globalScopeGuard = Binder::ScopeGuard{&binder_};
+
+  if (is_parsing_c()) {
+    if (unqualifiedId) {
+      // declared named structs in the enclosed non-class scope in C mode
+      setScope(getCurrentNonClassScope());
+    }
+  }
+
   auto ast = make_node<ClassSpecifierAST>(pool_);
   yyast = ast;
 

src/parser/cxx/type_checker.cc

@@ -2124,6 +2124,7 @@ auto TypeChecker::Visitor::check_member_access(MemberExpressionAST* ast)
     } else {
       (void)ensure_prvalue(ast->baseExpression);
       objectType = ast->baseExpression->type;
+      cv1 = strip_cv(objectType);
     }
 
     auto pointerType = type_cast<PointerType>(objectType);

tests/unit_tests/sema/class_02.cc

@@ -0,0 +1,20 @@
+// RUN: %cxx -verify -fcheck %s
+
+struct A {
+  struct {
+    int x;
+  };
+  union {
+    int y;
+    struct {
+      int z;
+    };
+  };
+};
+
+int main() {
+  struct A a;
+  (void)_Generic(a.x, int: 123);
+  (void)_Generic(a.y, int: 321);
+  (void)_Generic(a.z, int: 444);
+}