From 7d6fc23022d355b630993cabf139c8ae91354b9c Mon Sep 17 00:00:00 2001
From: abhijit-sawant <abhijit.abhi1980@gmail.com>
Date: Mon, 21 Dec 2020 01:14:52 -0500
Subject: [PATCH] Checking in fix for issue 9957 -  - False negative:
 duplInheritedMember (#2964)

---
 lib/checkclass.cpp | 32 +++++++++++++++++++-------------
 lib/checkclass.h   |  2 ++
 test/testclass.cpp | 14 ++++++++++++++
 3 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/lib/checkclass.cpp b/lib/checkclass.cpp
index d0c464d49..a6b5f0371 100644
--- a/lib/checkclass.cpp
+++ b/lib/checkclass.cpp
@@ -2439,22 +2439,28 @@ void CheckClass::checkDuplInheritedMembers()
     // Iterate over all classes
     for (const Type &classIt : mSymbolDatabase->typeList) {
         // Iterate over the parent classes
-        for (const Type::BaseInfo &parentClassIt : classIt.derivedFrom) {
-            // Check if there is info about the 'Base' class
-            if (!parentClassIt.type || !parentClassIt.type->classScope)
-                continue;
-            // Check if they have a member variable in common
-            for (const Variable &classVarIt : classIt.classScope->varlist) {
-                for (const Variable &parentClassVarIt : parentClassIt.type->classScope->varlist) {
-                    if (classVarIt.name() == parentClassVarIt.name() && !parentClassVarIt.isPrivate()) { // Check if the class and its parent have a common variable
-                        duplInheritedMembersError(classVarIt.nameToken(), parentClassVarIt.nameToken(),
-                                                  classIt.name(), parentClassIt.type->name(), classVarIt.name(),
-                                                  classIt.classScope->type == Scope::eStruct,
-                                                  parentClassIt.type->classScope->type == Scope::eStruct);
-                    }
+        checkDuplInheritedMembersRecursive(&classIt, &classIt);
+    }
+}
+
+void CheckClass::checkDuplInheritedMembersRecursive(const Type* typeCurrent, const Type* typeBase)
+{
+    for (const Type::BaseInfo &parentClassIt : typeBase->derivedFrom) {
+        // Check if there is info about the 'Base' class
+        if (!parentClassIt.type || !parentClassIt.type->classScope)
+            continue;
+        // Check if they have a member variable in common
+        for (const Variable &classVarIt : typeCurrent->classScope->varlist) {
+            for (const Variable &parentClassVarIt : parentClassIt.type->classScope->varlist) {
+                if (classVarIt.name() == parentClassVarIt.name() && !parentClassVarIt.isPrivate()) { // Check if the class and its parent have a common variable
+                    duplInheritedMembersError(classVarIt.nameToken(), parentClassVarIt.nameToken(),
+                                                typeCurrent->name(), parentClassIt.type->name(), classVarIt.name(),
+                                                typeCurrent->classScope->type == Scope::eStruct,
+                                                parentClassIt.type->classScope->type == Scope::eStruct);
                 }
             }
         }
+        checkDuplInheritedMembersRecursive(typeCurrent, parentClassIt.type);
     }
 }
 
diff --git a/lib/checkclass.h b/lib/checkclass.h
index cedd8f4fa..9649a309e 100644
--- a/lib/checkclass.h
+++ b/lib/checkclass.h
@@ -38,6 +38,7 @@ class Scope;
 class Settings;
 class SymbolDatabase;
 class Token;
+class Type;
 
 /// @addtogroup Checks
 /// @{
@@ -185,6 +186,7 @@ private:
     void overrideError(const Function *funcInBase, const Function *funcInDerived);
     void thisUseAfterFree(const Token *self, const Token *free, const Token *use);
     void unsafeClassRefMemberError(const Token *tok, const std::string &varname);
+    void checkDuplInheritedMembersRecursive(const Type* typeCurrent, const Type* typeBase);
 
     void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const OVERRIDE {
         CheckClass c(nullptr, settings, errorLogger);
diff --git a/test/testclass.cpp b/test/testclass.cpp
index 515525c56..1cfbf055b 100644
--- a/test/testclass.cpp
+++ b/test/testclass.cpp
@@ -557,6 +557,20 @@ private:
                                   "}");
         ASSERT_EQUALS("", errout.str());
 
+        // #9957
+        checkDuplInheritedMembers("class Base {\n"
+                                  "    public:\n"
+                                  "        int i;\n"
+                                  "};\n"
+                                  "class Derived1: public Base {\n"
+                                  "    public:\n"
+                                  "        int j;\n"
+                                  "};\n"
+                                  "class Derived2 : public Derived1 {\n"
+                                  "    int i;\n"  
+                                  "};");
+        ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:10]: (warning) The class 'Derived2' defines member variable with name 'i' also defined in its parent class 'Base'.\n", errout.str());        
+
     }
 
     void checkCopyConstructor(const char code[]) {