diff --git a/src/CBot/CBotCStack.cpp b/src/CBot/CBotCStack.cpp
index 5065ddfa..ba48ebcb 100644
--- a/src/CBot/CBotCStack.cpp
+++ b/src/CBot/CBotCStack.cpp
@@ -31,107 +31,100 @@
 namespace CBot
 {
 
-////////////////////////////////////////////////////////////////////////////////
-CBotProgram* CBotCStack::m_prog    = nullptr;            // init the static variable
-CBotError CBotCStack::m_error   = CBotNoErr;
-int CBotCStack::m_end      = 0;
-CBotTypResult CBotCStack::m_retTyp  = CBotTypResult(0);
+struct CBotCStack::Data
+{
+    //! The program currently being compiled
+    CBotProgram*  prog   = nullptr;
+    //! The current error state of the compile stack
+    CBotError     error  = CBotNoErr;
+    int           errEnd = 0;
+    //! The return type of the function currently being compiled
+    CBotTypResult retTyp = CBotTypResult(CBotTypVoid);
+};
 
-////////////////////////////////////////////////////////////////////////////////
 CBotCStack::CBotCStack(CBotCStack* ppapa)
 {
-    m_next = nullptr;
     m_prev = ppapa;
 
     if (ppapa == nullptr)
     {
-        m_error = CBotNoErr;
-        m_start = 0;
-        m_end    = 0;
+        m_data = new CBotCStack::Data;
+        m_errStart = 0;
         m_bBlock = true;
     }
     else
     {
-        m_start = ppapa->m_start;
+        m_data = ppapa->m_data;
+        m_errStart = ppapa->m_errStart;
         m_bBlock = false;
     }
-
-    m_listVar = nullptr;
-    m_var      = nullptr;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 CBotCStack::~CBotCStack()
 {
-    if (m_next != nullptr) delete m_next;
-    if (m_prev != nullptr) m_prev->m_next = nullptr;        // removes chain
-
-    delete m_var;
-    delete m_listVar;
+    if (m_prev == nullptr) delete m_data;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 CBotCStack* CBotCStack::TokenStack(CBotToken* pToken, bool bBlock)
 {
-    if (m_next != nullptr) return m_next;            // include on an existing stack
+    if (m_next) return m_next.get();                 // include on an existing stack
 
-    CBotCStack*    p = new CBotCStack(this);
-    m_next = p;                                    // channel element
-    p->m_bBlock = bBlock;
+    m_next.reset(new CBotCStack(this));
+    m_next->m_bBlock = bBlock;
 
-    if (pToken != nullptr) p->SetStartError(pToken->GetStart());
+    if (pToken != nullptr) m_next->SetStartError(pToken->GetStart());
 
-    return    p;
+    return m_next.get();
+}
+
+void CBotCStack::DeleteNext()
+{
+    m_next.reset();
 }
 
-////////////////////////////////////////////////////////////////////////////////
 CBotInstr* CBotCStack::Return(CBotInstr* inst, CBotCStack* pfils)
 {
     if ( pfils == this ) return inst;
 
-    if (m_var != nullptr) delete m_var;            // value replaced?
-    m_var = pfils->m_var;                        // result transmitted
-    pfils->m_var = nullptr;                        // not to destroy the variable
+    m_var = std::move(pfils->m_var);             // result transmitted
 
-    if (m_error)
+    if (m_data->error != CBotNoErr)
     {
-        m_start = pfils->m_start;                // retrieves the position of the error
-        m_end    = pfils->m_end;
+        m_errStart = pfils->m_errStart;          // retrieves the position of the error
     }
 
-    delete pfils;
+    m_next.reset();
     return inst;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 CBotFunction* CBotCStack::ReturnFunc(CBotFunction* inst, CBotCStack* pfils)
 {
-    if (m_var != nullptr) delete m_var;            // value replaced?
-    m_var = pfils->m_var;                        // result transmitted
-    pfils->m_var = nullptr;                        // not to destroy the variable
+    m_var = std::move(pfils->m_var);             // result transmitted
 
-    if (m_error)
+    if (m_data->error != CBotNoErr)
     {
-        m_start = pfils->m_start;                // retrieves the position of the error
-        m_end    = pfils->m_end;
+        m_errStart = pfils->m_errStart;          // retrieves the position of the error
     }
 
-    delete pfils;
+    m_next.reset();
     return inst;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 CBotError CBotCStack::GetError(int& start, int& end)
 {
-    start = m_start;
-    end      = m_end;
-    return m_error;
+    start = m_errStart;
+    end = m_data->errEnd;
+    return m_data->error;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 CBotError CBotCStack::GetError()
 {
-    return m_error;
+    return m_data->error;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -171,18 +164,13 @@ void CBotCStack::SetType(CBotTypResult& type)
 CBotVar* CBotCStack::FindVar(CBotToken* &pToken)
 {
     CBotCStack*    p = this;
-    std::string    name = pToken->GetString();
+    const auto&    name = pToken->GetString();
 
     while (p != nullptr)
     {
-        CBotVar*    pp = p->m_listVar;
-        while ( pp != nullptr)
+        if (p->m_bBlock) for (auto& var : p->m_listVar)
         {
-            if (name == pp->GetName())
-            {
-                return pp;
-            }
-            pp = pp->m_next;
+            if (name == var->GetName()) return var.get();
         }
         p = p->m_prev;
     }
@@ -211,39 +199,39 @@ CBotVar* CBotCStack::CopyVar(CBotToken& Token)
 ////////////////////////////////////////////////////////////////////////////////
 bool CBotCStack::IsOk()
 {
-    return (m_error == 0);
+    return (m_data->error == CBotNoErr);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 void CBotCStack::SetStartError( int pos )
 {
-    if ( m_error != 0) return;            // does not change existing error
-    m_start = pos;
+    if (m_data->error != CBotNoErr) return; // does not change existing error
+    m_errStart = pos;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 void CBotCStack::SetError(CBotError n, int pos)
 {
-    if ( n!= 0 && m_error != 0) return;    // does not change existing error
-    m_error = n;
-    m_end    = pos;
+    if (n != CBotNoErr && m_data->error != CBotNoErr) return; // does not change existing error
+    m_data->error = n;
+    m_data->errEnd = pos;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 void CBotCStack::SetError(CBotError n, CBotToken* p)
 {
-    if (m_error) return;    // does not change existing error
-    m_error = n;
-    m_start    = p->GetStart();
-    m_end    = p->GetEnd();
+    if (m_data->error != CBotNoErr) return; // does not change existing error
+    m_data->error = n;
+    m_errStart = p->GetStart();
+    m_data->errEnd = p->GetEnd();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 void CBotCStack::ResetError(CBotError n, int start, int end)
 {
-    m_error = n;
-    m_start    = start;
-    m_end    = end;
+    m_data->error = n;
+    m_errStart = start;
+    m_data->errEnd = end;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -261,48 +249,47 @@ bool CBotCStack::NextToken(CBotToken* &p)
 ////////////////////////////////////////////////////////////////////////////////
 void CBotCStack::SetProgram(CBotProgram* p)
 {
-    m_prog = p;
+    m_data->prog = p;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 CBotProgram* CBotCStack::GetProgram()
 {
-    return m_prog;
+    return m_data->prog;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 void CBotCStack::SetRetType(CBotTypResult& type)
 {
-    m_retTyp = type;
+    m_data->retTyp = type;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 CBotTypResult CBotCStack::GetRetType()
 {
-    return m_retTyp;
+    return m_data->retTyp;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 void CBotCStack::SetVar( CBotVar* var )
 {
-    if (m_var) delete m_var;    // replacement of a variable
-    m_var = var;
+    m_var.reset(var);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 void CBotCStack::SetCopyVar( CBotVar* var )
 {
-    if (m_var) delete m_var;    // replacement of a variable
+    m_var.reset();
 
     if ( var == nullptr ) return;
-    m_var = CBotVar::Create("", var->GetTypResult(CBotVar::GetTypeMode::CLASS_AS_INTRINSIC));
+    m_var.reset(CBotVar::Create("", var->GetTypResult(CBotVar::GetTypeMode::CLASS_AS_INTRINSIC)));
     m_var->Copy( var );
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 CBotVar* CBotCStack::GetVar()
 {
-    return m_var;
+    return m_var.get();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -310,15 +297,12 @@ void CBotCStack::AddVar(CBotVar* pVar)
 {
     CBotCStack*    p = this;
 
-    // returns to the father element
+    // find the level of the current block
     while (p != nullptr && p->m_bBlock == 0) p = p->m_prev;
 
-    if ( p == nullptr ) return;
+    if (p == nullptr || pVar == nullptr) return;
 
-    CBotVar**    pp = &p->m_listVar;
-    while ( *pp != nullptr ) pp = &(*pp)->m_next;
-
-    *pp = pVar;                    // added after
+    p->m_listVar.emplace_back(pVar);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -369,19 +353,14 @@ void CBotCStack::CreateMemberVars(CBotClass* pClass, bool setDefined)
 bool CBotCStack::CheckVarLocal(CBotToken* &pToken)
 {
     CBotCStack*    p = this;
-    std::string    name = pToken->GetString();
+    const auto&    name = pToken->GetString();
 
-    while (p != nullptr)
+    // find the level of the current block
+    while (p != nullptr && p->m_bBlock == 0) p = p->m_prev;
+
+    if (p != nullptr) for (auto& var : p->m_listVar)
     {
-        CBotVar*    pp = p->m_listVar;
-        while ( pp != nullptr)
-        {
-            if (name == pp->GetName())
-                return true;
-            pp = pp->m_next;
-        }
-        if ( p->m_bBlock ) return false;
-        p = p->m_prev;
+        if (name == var->GetName()) return true;
     }
     return false;
 }
@@ -392,10 +371,10 @@ CBotTypResult CBotCStack::CompileCall(CBotToken* &p, CBotVar** ppVars, long& nId
     nIdent = 0;
     CBotTypResult val(-1);
 
-    val = m_prog->GetExternalCalls()->CompileCall(p, nullptr, ppVars, this);
+    val = GetProgram()->GetExternalCalls()->CompileCall(p, nullptr, ppVars, this);
     if (val.GetType() < 0)
     {
-        val = CBotFunction::CompileCall(p->GetString(), ppVars, nIdent, m_prog);
+        val = CBotFunction::CompileCall(p->GetString(), ppVars, nIdent, GetProgram());
         if ( val.GetType() < 0 )
         {
     //        pVar = nullptr;                    // the error is not on a particular parameter
@@ -410,13 +389,13 @@ CBotTypResult CBotCStack::CompileCall(CBotToken* &p, CBotVar** ppVars, long& nId
 ////////////////////////////////////////////////////////////////////////////////
 bool CBotCStack::CheckCall(CBotToken* &pToken, CBotDefParam* pParam, const std::string& className)
 {
-    std::string    name = pToken->GetString();
+    const auto& name = pToken->GetString();
 
-    if ( m_prog->GetExternalCalls()->CheckCall(name) ) return true;
+    if ( GetProgram()->GetExternalCalls()->CheckCall(name) ) return true;
 
-    for (CBotFunction* pp : m_prog->GetFunctions())
+    for (CBotFunction* pp : GetProgram()->GetFunctions())
     {
-        if ( pToken->GetString() == pp->GetName() )
+        if ( name == pp->GetName() )
         {
             // ignore methods for a different class
             if ( className != pp->GetClassName() )
@@ -429,7 +408,7 @@ bool CBotCStack::CheckCall(CBotToken* &pToken, CBotDefParam* pParam, const std::
 
     for (CBotFunction* pp : CBotFunction::m_publicFunctions)
     {
-        if ( pToken->GetString() == pp->GetName() )
+        if ( name == pp->GetName() )
         {
             // ignore methods for a different class
             if ( className != pp->GetClassName() )
@@ -443,4 +422,4 @@ bool CBotCStack::CheckCall(CBotToken* &pToken, CBotDefParam* pParam, const std::
     return false;
 }
 
-}
+} // namespace CBot
diff --git a/src/CBot/CBotCStack.h b/src/CBot/CBotCStack.h
index 983dcf42..adcbee59 100644
--- a/src/CBot/CBotCStack.h
+++ b/src/CBot/CBotCStack.h
@@ -22,6 +22,9 @@
 #include "CBot/CBotVar/CBotVar.h"
 #include "CBot/CBotProgram.h"
 
+#include <list>
+#include <memory>
+
 namespace CBot
 {
 
@@ -157,6 +160,11 @@ public:
      */
     CBotCStack* TokenStack(CBotToken* pToken = nullptr, bool bBlock = false);
 
+    /*!
+     * \brief Deletes all subsequent stack frames created by TokenStack.
+     */
+    void DeleteNext();
+
     /*!
      * \brief Return Transmits the result upper.
      * \param p
@@ -269,21 +277,20 @@ public:
     bool NextToken(CBotToken* &p);
 
 private:
-    CBotCStack* m_next;
+    std::unique_ptr<CBotCStack> m_next;
     CBotCStack* m_prev;
 
-    static CBotError m_error;
-    static int m_end;
-    int m_start;
+    int m_errStart = 0;
+
+    struct Data;
+
+    CBotCStack::Data* m_data;
 
     //! Result of the operations.
-    CBotVar* m_var;
+    std::unique_ptr<CBotVar> m_var;
     //! Is part of a block (variables are local to this block).
     bool m_bBlock;
-    CBotVar* m_listVar;
-    //! List of compiled functions.
-    static CBotProgram* m_prog;
-    static CBotTypResult m_retTyp;
+    std::list<std::unique_ptr<CBotVar>> m_listVar;
 };
 
 } // namespace CBot
diff --git a/src/CBot/CBotClass.cpp b/src/CBot/CBotClass.cpp
index ccf47104..a7993a9a 100644
--- a/src/CBot/CBotClass.cpp
+++ b/src/CBot/CBotClass.cpp
@@ -605,8 +605,8 @@ bool CBotClass::CompileDefItem(CBotToken* &p, CBotCStack* pStack, bool bSecond)
                     // return a method precompiled in pass 1
                     CBotCStack* pStk = pStack->TokenStack(nullptr, true);
                     CBotDefParam* params = CBotDefParam::Compile(p, pStk );
-                    delete pStk;
-                    std::list<CBotFunction*>::iterator pfIter = std::find_if(m_pMethod.begin(), m_pMethod.end(), [&pp, &params](CBotFunction* x)
+                    pStack->DeleteNext();
+                    auto pfIter = std::find_if(m_pMethod.begin(), m_pMethod.end(), [&pp, &params](CBotFunction* x)
                     {
                         return x->GetName() == pp && x->CheckParam( params );
                     });
@@ -626,7 +626,7 @@ bool CBotClass::CompileDefItem(CBotToken* &p, CBotCStack* pStack, bool bSecond)
                         f->m_pProg = pStack->GetProgram();
                         f->m_bSynchro = bSynchro;
                     }
-                    pStack->Return(nullptr, pile);
+                    pStack->DeleteNext();
                 }
 
                 return pStack->IsOk();
diff --git a/src/CBot/CBotDefParam.cpp b/src/CBot/CBotDefParam.cpp
index 75be07eb..d25f9bda 100644
--- a/src/CBot/CBotDefParam.cpp
+++ b/src/CBot/CBotDefParam.cpp
@@ -94,7 +94,7 @@ CBotDefParam* CBotDefParam::Compile(CBotToken* &p, CBotCStack* pStack)
                             prevHasDefault = true;
                         }
                         else pStack->SetError(CBotErrNoExpression, p);
-                        delete pStk;
+                        pStack->DeleteNext();
                     }
                     else
                         if (prevHasDefault) pStack->SetError(CBotErrDefaultValue, p->GetPrev());
diff --git a/src/CBot/CBotInstr/CBotDefClass.cpp b/src/CBot/CBotInstr/CBotDefClass.cpp
index 640b56eb..f50196ed 100644
--- a/src/CBot/CBotInstr/CBotDefClass.cpp
+++ b/src/CBot/CBotInstr/CBotDefClass.cpp
@@ -135,7 +135,7 @@ CBotInstr* CBotDefClass::Compile(CBotToken* &p, CBotCStack* pStack, CBotClass* p
             // the constructor is there?
 //          std::string  noname;
             CBotTypResult r = pClass->CompileMethode(&token, var, ppVars, pStk, inst->m_nMethodeIdent);
-            delete pStk->TokenStack();                          // releases the supplement stack
+            pStk->DeleteNext();                                 // releases the supplement stack
             int typ = r.GetType();
 
             if (typ == CBotErrUndefCall)
@@ -160,7 +160,7 @@ CBotInstr* CBotDefClass::Compile(CBotToken* &p, CBotCStack* pStack, CBotClass* p
             if (nullptr != (inst->m_exprRetVar = CBotExprRetVar::Compile(p, pStk, true)))
             {
                 inst->m_exprRetVar->SetToken(vartoken);
-                delete pStk->TokenStack();
+                pStk->DeleteNext();
             }
             pStk->SetVar(nullptr);
 
diff --git a/src/CBot/CBotInstr/CBotInstrCall.cpp b/src/CBot/CBotInstr/CBotInstrCall.cpp
index b3d151a7..2274f3ac 100644
--- a/src/CBot/CBotInstr/CBotInstrCall.cpp
+++ b/src/CBot/CBotInstr/CBotInstrCall.cpp
@@ -78,12 +78,12 @@ CBotInstr* CBotInstrCall::Compile(CBotToken* &p, CBotCStack* pStack)
         {
 //          if (pVar2!=nullptr) pp = pVar2->RetToken();
             pStack->SetError( static_cast<CBotError>(inst->m_typRes.GetType()), pp );
-            delete pStack->TokenStack();
+            pStack->DeleteNext();
             delete inst;
             return nullptr;
         }
 
-        delete pStack->TokenStack();
+        pStack->DeleteNext();
         if ( inst->m_typRes.GetType() > 0 )
         {
             CBotVar* pRes = CBotVar::Create("", inst->m_typRes);
@@ -94,7 +94,7 @@ CBotInstr* CBotInstrCall::Compile(CBotToken* &p, CBotCStack* pStack)
         if (nullptr != (inst->m_exprRetVar = CBotExprRetVar::Compile(p, pStack)))
         {
             inst->m_exprRetVar->SetToken(&inst->m_token);
-            delete pStack->TokenStack();
+            pStack->DeleteNext();
         }
         if ( !pStack->IsOk() )
         {
@@ -105,7 +105,7 @@ CBotInstr* CBotInstrCall::Compile(CBotToken* &p, CBotCStack* pStack)
         return inst;
     }
     p = pp;
-    delete pStack->TokenStack();
+    pStack->DeleteNext();
     return nullptr;
 }
 
diff --git a/src/CBot/CBotInstr/CBotInstrMethode.cpp b/src/CBot/CBotInstr/CBotInstrMethode.cpp
index a69ae7c9..6b7045e3 100644
--- a/src/CBot/CBotInstr/CBotInstrMethode.cpp
+++ b/src/CBot/CBotInstr/CBotInstrMethode.cpp
@@ -70,7 +70,7 @@ CBotInstr* CBotInstrMethode::Compile(CBotToken* &p, CBotCStack* pStack, CBotVar*
             CBotClass* pClass = var->GetClass();    // pointer to the class
             inst->m_className = pClass->GetName();  // name of the class
             CBotTypResult r = pClass->CompileMethode(pp, var, ppVars, pStack, inst->m_MethodeIdent);
-            delete pStack->TokenStack();    // release parameters on the stack
+            pStack->DeleteNext();           // release parameters on the stack
             inst->m_typRes = r;
 
             if (inst->m_typRes.GetType() > 20)
@@ -95,7 +95,7 @@ CBotInstr* CBotInstrMethode::Compile(CBotToken* &p, CBotCStack* pStack, CBotVar*
             if (nullptr != (inst->m_exprRetVar = CBotExprRetVar::Compile(p, pStack, bMethodChain)))
             {
                 inst->m_exprRetVar->SetToken(pp);
-                delete pStack->TokenStack();
+                pStack->DeleteNext();
             }
 
             if ( pStack->IsOk() )
diff --git a/src/CBot/CBotInstr/CBotInstrUtils.cpp b/src/CBot/CBotInstr/CBotInstrUtils.cpp
index 0b56267c..c4638d60 100644
--- a/src/CBot/CBotInstr/CBotInstrUtils.cpp
+++ b/src/CBot/CBotInstr/CBotInstrUtils.cpp
@@ -65,7 +65,7 @@ CBotInstr* CompileParams(CBotToken* &p, CBotCStack* pStack, CBotVar** ppVars)
             {
                 if (pile->GetTypResult().Eq(99))
                 {
-                    delete pStack->TokenStack();
+                    pStack->DeleteNext();
                     pStack->SetError(CBotErrVoid, p->GetStart());
                     return nullptr;
                 }
@@ -78,7 +78,7 @@ CBotInstr* CompileParams(CBotToken* &p, CBotCStack* pStack, CBotVar** ppVars)
             }
 
             pStack->SetError(CBotErrClosePar, p->GetStart());
-            delete pStack->TokenStack();
+            pStack->DeleteNext();
             return nullptr;
         }
     }
diff --git a/src/CBot/CBotInstr/CBotNew.cpp b/src/CBot/CBotInstr/CBotNew.cpp
index b97f4e68..dd8d04ac 100644
--- a/src/CBot/CBotInstr/CBotNew.cpp
+++ b/src/CBot/CBotInstr/CBotNew.cpp
@@ -87,7 +87,7 @@ CBotInstr* CBotNew::Compile(CBotToken* &p, CBotCStack* pStack)
 
         // constructor exist?
         CBotTypResult r = pClass->CompileMethode(&inst->m_vartoken, pVar, ppVars, pStk, inst->m_nMethodeIdent);
-        delete pStk->TokenStack();  // release extra stack
+        pStk->DeleteNext(); // release extra stack
         int typ = r.GetType();
 
         // if there is no constructor, and no parameters either, it's ok
@@ -115,7 +115,7 @@ CBotInstr* CBotNew::Compile(CBotToken* &p, CBotCStack* pStack)
         if (nullptr != (inst->m_exprRetVar = CBotExprRetVar::Compile(p, pStk, true)))
         {
             inst->m_exprRetVar->SetToken(pp);
-            delete pStk->TokenStack();
+            pStk->DeleteNext();
         }
 
         if (pStack->IsOk())
diff --git a/src/CBot/CBotInstr/CBotSwitch.cpp b/src/CBot/CBotInstr/CBotSwitch.cpp
index 9436407b..c75e9aa1 100644
--- a/src/CBot/CBotInstr/CBotSwitch.cpp
+++ b/src/CBot/CBotInstr/CBotSwitch.cpp
@@ -71,7 +71,7 @@ CBotInstr* CBotSwitch::Compile(CBotToken* &p, CBotCStack* pStack)
                         {
                             if ( p->GetType() == ID_CASE || p->GetType() == ID_DEFAULT)
                             {
-                                delete pStk2;
+                                pStk->DeleteNext();
                                 pStk2 = pStk->TokenStack(p, true);          // some space for a stack, plz
 
                                 caseInst = static_cast<CBotCase*>(CBotCase::Compile(p, pStk2, inst->m_labels));