Issue 9255: Prevent infinite recursion in parsedecl (#2134)

Author: Ken-Patrick

lib/symboldatabase.cpp

@@ -5271,6 +5271,7 @@ void SymbolDatabase::setValueType(Token *tok, const ValueType &valuetype)
 
 static const Token * parsedecl(const Token *type, ValueType * const valuetype, ValueType::Sign defaultSignedness, const Settings* settings)
 {
+    const Token * const previousType = type;
     const unsigned int pointer0 = valuetype->pointer;
     while (Token::Match(type->previous(), "%name%"))
         type = type->previous();
@@ -5305,7 +5306,7 @@ static const Token * parsedecl(const Token *type, ValueType * const valuetype, V
             valuetype->sign = ValueType::Sign::UNSIGNED;
         if (valuetype->type == ValueType::Type::UNKNOWN_TYPE &&
             type->type() && type->type()->isTypeAlias() && type->type()->typeStart &&
-            type->type()->typeStart->str() != type->str())
+            type->type()->typeStart->str() != type->str() && type->type()->typeStart != previousType)
             parsedecl(type->type()->typeStart, valuetype, defaultSignedness, settings);
         else if (type->str() == "const")
             valuetype->constness |= (1 << (valuetype->pointer - pointer0));

test/testsymboldatabase.cpp

@@ -396,6 +396,8 @@ class TestSymbolDatabase: public TestFixture {
         TEST_CASE(auto12); // #8993 - const std::string &x; auto y = x; if (y.empty()) ..
 
         TEST_CASE(unionWithConstructor);
+
+        TEST_CASE(incomplete_type); // #9255 (infinite recursion)
     }
 
     void array() {
@@ -7073,6 +7075,25 @@ class TestSymbolDatabase: public TestFixture {
         f = Token::findsimplematch(tokenizer.tokens(), "Fred ( float");
         ASSERT_EQUALS(true, db && f && f->function() && f->function()->tokenDef->linenr() == 3);
     }
+
+    void incomplete_type() {
+        GET_SYMBOL_DB("template<class _Ty,\n"
+                      "  class _Alloc = std::allocator<_Ty>>\n"
+					  "  class SLSurfaceLayerData\n"
+					  "  : public _Vector_alloc<_Vec_base_types<_Ty, _Alloc>>\n"
+					  "{     // varying size array of values\n"
+					  "\n"
+					  "  using reverse_iterator = _STD reverse_iterator<iterator>;\n"
+					  "  using const_reverse_iterator = _STD reverse_iterator<const_iterator>;\n"
+					  "  const_reverse_iterator crend() const noexcept\n"
+					  "  {   // return iterator for end of reversed nonmutable sequence\n"
+					  "    return (rend());\n"
+					  "  }\n"
+					  "};");
+        (void)db;
+
+        ASSERT_EQUALS("", errout.str());
+    }
 };
 
 REGISTER_TEST(TestSymbolDatabase)