Fixed #4391 (False positive: ctor not detected after variable declaration)

lib/checkclass.cpp

@@ -57,6 +57,10 @@ void CheckClass::constructors()
     for (std::size_t i = 0; i < classes; ++i) {
         const Scope * scope = symbolDatabase->classAndStructScopes[i];
 
+        // skip forward declarations
+        if (scope->isForwardDeclaration())
+            continue;
+
         // don't check uninstantiated template classes
         if (scope->classDef->strAt(-1) == ">")
             continue;

test/testclass.cpp

@@ -51,6 +51,7 @@ private:
         TEST_CASE(noConstructor4);
         TEST_CASE(noConstructor5);
         TEST_CASE(noConstructor6); // ticket #4386
+        TEST_CASE(noConstructor7); // ticket #4391
 
         TEST_CASE(operatorEq1);
         TEST_CASE(operatorEq2);
@@ -1896,6 +1897,13 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void noConstructor7() {
+        // ticket #4391
+        checkNoConstructor("short bar;\n"
+                           "class foo;\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void checkNoMemset(const char code[]) {
         // Clear the error log
         errout.str("");