LibCpp: Support 'auto' Type

Userland/Libraries/LibCpp/AST.cpp

@@ -76,7 +76,14 @@ String Type::to_string() const
     String qualifiers_string;
     if (!m_qualifiers.is_empty())
         qualifiers_string = String::formatted("[{}] ", String::join(" ", m_qualifiers));
-    return String::formatted("{}{}", qualifiers_string, m_name.is_null() ? "" : m_name->full_name());
+
+    String name;
+    if (m_is_auto)
+        name = "auto";
+    else
+        name = m_name.is_null() ? "" : m_name->full_name();
+
+    return String::formatted("{}{}", qualifiers_string, name);
 }
 
 String Pointer::to_string() const

Userland/Libraries/LibCpp/AST.h

@@ -206,6 +206,7 @@ public:
     {
     }
 
+    bool m_is_auto { false };
     RefPtr<Name> m_name;
     Vector<StringView> m_qualifiers;
 };

Userland/Libraries/LibCpp/Parser.cpp

@@ -235,6 +235,10 @@ bool Parser::match_type()
     ScopeGuard state_guard = [this] { load_state(); };
 
     parse_type_qualifiers();
+    if (match_keyword("auto")) {
+        return true;
+    }
+
     if (match_keyword("struct")) {
         consume(Token::Type::Keyword); // Consume struct prefix
     }
@@ -1104,16 +1108,22 @@ NonnullRefPtr<Type> Parser::parse_type(ASTNode& parent)
     auto qualifiers = parse_type_qualifiers();
     type->m_qualifiers = move(qualifiers);
 
-    if (match_keyword("struct")) {
-        consume(Token::Type::Keyword); // Consume struct prefix
-    }
+    if (match_keyword("auto")) {
+        consume(Token::Type::Keyword);
+        type->m_is_auto = true;
+    } else {
 
-    if (!match_name()) {
-        type->set_end(position());
-        error(String::formatted("expected name instead of: {}", peek().text()));
-        return type;
+        if (match_keyword("struct")) {
+            consume(Token::Type::Keyword); // Consume struct prefix
+        }
+
+        if (!match_name()) {
+            type->set_end(position());
+            error(String::formatted("expected name instead of: {}", peek().text()));
+            return type;
+        }
+        type->m_name = parse_name(*type);
     }
-    type->m_name = parse_name(*type);
 
     while (!eof() && peek().type() == Token::Type::Asterisk) {
         type->set_end(position());