diff --git a/lib/checkclass.cpp b/lib/checkclass.cpp
index 374cee66b..37d550c2a 100644
--- a/lib/checkclass.cpp
+++ b/lib/checkclass.cpp
@@ -206,7 +206,7 @@ void CheckClass::constructors()
         std::vector<Usage> usageList = createUsageList(scope);
 
         for (const Function &func : scope->functionList) {
-            if (!func.hasBody() || !(func.isConstructor() || func.type == Function::eOperatorEqual))
+            if ((!func.hasBody() && !func.isDefault()) || !(func.isConstructor() || func.type == Function::eOperatorEqual))
                 continue;
 
             // Bail: If initializer list is not recognized as a variable or type then skip since parsing is incomplete
@@ -694,7 +694,8 @@ bool CheckClass::isBaseClassFunc(const Token *tok, const Scope *scope)
 void CheckClass::initializeVarList(const Function &func, std::list<const Function *> &callstack, const Scope *scope, std::vector<Usage> &usage)
 {
     if (!func.functionScope)
-        throw InternalError(nullptr, "Internal Error: Invalid syntax"); // #5702
+        return;
+
     bool initList = func.isConstructor();
     const Token *ftok = func.arg->link()->next();
     int level = 0;
diff --git a/lib/ctu.h b/lib/ctu.h
index e5cd5b755..7379fc398 100644
--- a/lib/ctu.h
+++ b/lib/ctu.h
@@ -60,18 +60,18 @@ namespace CTU {
             Location(const Tokenizer *tokenizer, const Token *tok);
             Location(const std::string &fileName, nonneg int lineNumber, nonneg int column) : fileName(fileName), lineNumber(lineNumber), column(column) {}
             std::string fileName;
-            nonneg int lineNumber;
-            nonneg int column;
+            nonneg int lineNumber{};
+            nonneg int column{};
         };
 
         struct UnsafeUsage {
             UnsafeUsage() = default;
             UnsafeUsage(const std::string &myId, nonneg int myArgNr, const std::string &myArgumentName, const Location &location, MathLib::bigint value) : myId(myId), myArgNr(myArgNr), myArgumentName(myArgumentName), location(location), value(value) {}
             std::string myId;
-            nonneg int myArgNr;
+            nonneg int myArgNr{};
             std::string myArgumentName;
             Location location;
-            MathLib::bigint value;
+            MathLib::bigint value{};
             std::string toString() const;
         };
 
@@ -84,7 +84,7 @@ namespace CTU {
             CallBase(const Tokenizer *tokenizer, const Token *callToken);
             virtual ~CallBase() {}
             std::string callId;
-            int callArgNr;
+            int callArgNr{};
             std::string callFunctionName;
             Location location;
         protected:
@@ -119,7 +119,7 @@ namespace CTU {
             bool loadFromXml(const tinyxml2::XMLElement *xmlElement);
 
             std::string myId;
-            nonneg int myArgNr;
+            nonneg int myArgNr{};
         };
 
         std::list<FunctionCall> functionCalls;
diff --git a/test/testconstructors.cpp b/test/testconstructors.cpp
index 99d66e873..4173b165f 100644
--- a/test/testconstructors.cpp
+++ b/test/testconstructors.cpp
@@ -422,14 +422,20 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
-    void simple10() { // ticket #4388
-        check("class Fred {\n"
+    void simple10() {
+        check("class Fred {\n" // ticket #4388
               "public:\n"
               "    Fred() = default;\n"
               "private:\n"
               "    int x;\n"
               "};");
-        ASSERT_EQUALS("", errout.str());
+        ASSERT_EQUALS("[test.cpp:3]: (warning) Member variable 'Fred::x' is not initialized in the constructor.\n", errout.str());
+
+        check("struct S {\n" // #9391
+              "    S() = default;\n"
+              "    int i;\n"
+              "};\n");
+        ASSERT_EQUALS("[test.cpp:2]: (warning) Member variable 'S::i' is not initialized in the constructor.\n", errout.str());
     }
 
     void simple11() { // ticket #4536, #6214