diff --git a/src/CBot/CBotInstr/CBotDefArray.cpp b/src/CBot/CBotInstr/CBotDefArray.cpp
index 2cb05aa0..c70c8f9b 100644
--- a/src/CBot/CBotInstr/CBotDefArray.cpp
+++ b/src/CBot/CBotInstr/CBotDefArray.cpp
@@ -72,19 +72,26 @@ CBotInstr* CBotDefArray::Compile(CBotToken* &p, CBotCStack* pStack, CBotTypResul
         CBotInstr*    i;
         while (IsOfType(p,  ID_OPBRK))
         {
+            pStk->SetStartError(p->GetStart());
             if (p->GetType() != ID_CLBRK)
-                i = CBotExpression::Compile(p, pStk);                   // expression for the value
+            {
+                i = CBotExpression::Compile(p, pStk);                  // expression for the value
+                if (i == nullptr || pStk->GetType() >= CBotTypBoolean) // must be a number
+                {
+                    pStk->SetError(CBotErrBadIndex, p->GetStart());
+                    goto error;
+                }
+            }
             else
                 i = new CBotEmpty();                                    // if no special formula
 
             inst->AddNext3b(i);                                         // construct a list
             type = CBotTypResult(CBotTypArrayPointer, type);
 
-            if (!pStk->IsOk() || !IsOfType(p, ID_CLBRK ))
-            {
-                pStk->SetError(CBotErrCloseIndex, p->GetStart());
-                goto error;
-            }
+            if (IsOfType(p, ID_CLBRK)) continue;
+
+            pStk->SetError(CBotErrCloseIndex, p->GetStart());
+            goto error;
         }
 
         CBotVar*   var = CBotVar::Create(*vartoken, type);               // create an instance
@@ -96,17 +103,23 @@ CBotInstr* CBotDefArray::Compile(CBotToken* &p, CBotCStack* pStack, CBotTypResul
 
         if (IsOfType(p, ID_ASS))                                        // with an assignment
         {
-            if ((inst->m_listass = CBotTwoOpExpr::Compile(p, pStk)) != nullptr)
+            pStk->SetStartError(p->GetStart());
+            if ( IsOfType(p, ID_SEP) )
             {
-                if (!pStk->GetTypResult().Compare(type))  // compatible type ?
-                {
-                    pStk->SetError(CBotErrBadType1, p->GetStart());
-                    goto error;
-                }
+                pStk->SetError(CBotErrBadLeft, p->GetPrev());
+                goto error;
             }
-            else
+            if ( nullptr == (inst->m_listass = CBotListArray::Compile(p, pStk, type.GetTypElem())) )
             {
-                inst->m_listass = CBotListArray::Compile(p, pStk, type.GetTypElem());
+                if (pStk->IsOk())
+                {
+                    inst->m_listass = CBotTwoOpExpr::Compile(p, pStk);
+                    if (inst->m_listass == nullptr || !pStk->GetTypResult().Compare(type))  // compatible type ?
+                    {
+                        pStk->SetError(CBotErrBadType1, p->GetStart());
+                        goto error;
+                    }
+                }
             }
         }
 
diff --git a/src/CBot/CBotInstr/CBotDefBoolean.cpp b/src/CBot/CBotInstr/CBotDefBoolean.cpp
index bcac0722..63b9d346 100644
--- a/src/CBot/CBotInstr/CBotDefBoolean.cpp
+++ b/src/CBot/CBotInstr/CBotDefBoolean.cpp
@@ -82,16 +82,17 @@ CBotInstr* CBotDefBoolean::Compile(CBotToken* &p, CBotCStack* pStack, bool cont,
 
             inst = static_cast<CBotDefBoolean*>(CBotDefArray::Compile(p, pStk, CBotTypBoolean));
 
-            if (!pStk->IsOk() )
-            {
-                pStk->SetError(CBotErrCloseIndex, p->GetStart());
-                goto error;
-            }
             goto suite;            // no assignment, variable already created
         }
 
         if (IsOfType(p,  ID_ASS))
         {
+            pStk->SetStartError(p->GetStart());
+            if ( IsOfType(p, ID_SEP) )
+            {
+                pStk->SetError(CBotErrBadLeft, p->GetPrev());
+                goto error;
+            }
             if (nullptr == ( inst->m_expr = CBotTwoOpExpr::Compile( p, pStk )))
             {
                 goto error;
@@ -109,7 +110,7 @@ CBotInstr* CBotDefBoolean::Compile(CBotToken* &p, CBotCStack* pStack, bool cont,
             (static_cast<CBotLeftExprVar*>(inst->m_var))->m_nIdent = CBotVar::NextUniqNum());
         pStack->AddVar(var);
 suite:
-        if (IsOfType(p,  ID_COMMA))
+        if (pStk->IsOk() && IsOfType(p,  ID_COMMA))
         {
             if (nullptr != ( inst->m_next2b = CBotDefBoolean::Compile(p, pStk, true, noskip)))
             {
diff --git a/src/CBot/CBotInstr/CBotDefClass.cpp b/src/CBot/CBotInstr/CBotDefClass.cpp
index 39ac6afa..72ec71ec 100644
--- a/src/CBot/CBotInstr/CBotDefClass.cpp
+++ b/src/CBot/CBotInstr/CBotDefClass.cpp
@@ -101,11 +101,6 @@ CBotInstr* CBotDefClass::Compile(CBotToken* &p, CBotCStack* pStack, CBotClass* p
 
             inst = static_cast<CBotDefClass*>(CBotDefArray::Compile(p, pStk, type ));
 
-            if (!pStk->IsOk() )
-            {
-                pStk->SetError(CBotErrCloseIndex, p->GetStart());
-                goto error;
-            }
             goto suite;         // no assignment, variable already created
         }
 
@@ -159,6 +154,12 @@ CBotInstr* CBotDefClass::Compile(CBotToken* &p, CBotCStack* pStack, CBotClass* p
 
         if (IsOfType(p,  ID_ASS))                           // with a assignment?
         {
+            pStk->SetStartError(p->GetStart());
+            if ( IsOfType(p, ID_SEP) )
+            {
+                pStk->SetError(CBotErrBadLeft, p->GetPrev());
+                goto error;
+            }
             if (inst->m_hasParams)
             {
                 pStk->SetError(CBotErrNoTerminator, p->GetStart());
@@ -200,7 +201,7 @@ CBotInstr* CBotDefClass::Compile(CBotToken* &p, CBotCStack* pStack, CBotClass* p
             var->SetInit(CBotVar::InitType::IS_POINTER);                            // marks the pointer as init
         }
 suite:
-        if (IsOfType(p,  ID_COMMA))                         // several chained definitions
+        if (pStk->IsOk() && IsOfType(p,  ID_COMMA))                         // several chained definitions
         {
             if ( nullptr != ( inst->m_next = CBotDefClass::Compile(p, pStk, pClass) ))    // compiles the following
             {
@@ -208,7 +209,7 @@ suite:
             }
         }
 
-        if (IsOfType(p,  ID_SEP))                           // complete instruction
+        if (!pStk->IsOk() || IsOfType(p,  ID_SEP))           // complete instruction
         {
             return pStack->Return(inst, pStk);
         }
diff --git a/src/CBot/CBotInstr/CBotDefFloat.cpp b/src/CBot/CBotInstr/CBotDefFloat.cpp
index 9a99662f..33398fa2 100644
--- a/src/CBot/CBotInstr/CBotDefFloat.cpp
+++ b/src/CBot/CBotInstr/CBotDefFloat.cpp
@@ -81,16 +81,17 @@ CBotInstr* CBotDefFloat::Compile(CBotToken* &p, CBotCStack* pStack, bool cont, b
             p = vartoken;
             inst = static_cast<CBotDefFloat*>(CBotDefArray::Compile(p, pStk, CBotTypFloat));
 
-            if (!pStk->IsOk() )
-            {
-                pStk->SetError(CBotErrCloseIndex, p->GetStart());
-                goto error;
-            }
             goto suite;            // no assignment, variable already created
         }
 
         if (IsOfType(p,  ID_ASS))
         {
+            pStk->SetStartError(p->GetStart());
+            if ( IsOfType(p, ID_SEP) )
+            {
+                pStk->SetError(CBotErrBadLeft, p->GetPrev());
+                goto error;
+            }
             if (nullptr == ( inst->m_expr = CBotTwoOpExpr::Compile( p, pStk )))
             {
                 goto error;
@@ -108,7 +109,7 @@ CBotInstr* CBotDefFloat::Compile(CBotToken* &p, CBotCStack* pStack, bool cont, b
             (static_cast<CBotLeftExprVar*>(inst->m_var))->m_nIdent = CBotVar::NextUniqNum());
         pStack->AddVar(var);
 suite:
-        if (IsOfType(p,  ID_COMMA))
+        if (pStk->IsOk() && IsOfType(p,  ID_COMMA))
         {
             if (nullptr != ( inst->m_next2b = CBotDefFloat::Compile(p, pStk, true, noskip)))
             {
diff --git a/src/CBot/CBotInstr/CBotDefInt.cpp b/src/CBot/CBotInstr/CBotDefInt.cpp
index 360eb22b..9f7dcb61 100644
--- a/src/CBot/CBotInstr/CBotDefInt.cpp
+++ b/src/CBot/CBotInstr/CBotDefInt.cpp
@@ -84,25 +84,18 @@ CBotInstr* CBotDefInt::Compile(CBotToken* &p, CBotCStack* pStack, bool cont, boo
 
             CBotInstr* inst2 = CBotDefArray::Compile(p, pStk, CBotTypInt);
 
-            if (!pStk->IsOk() )
-            {
-                pStk->SetError(CBotErrCloseIndex, p->GetStart());
-                goto error;
-            }
-
-            if (IsOfType(p,  ID_COMMA))     // several definition chained
-            {
-                if (nullptr != ( inst2->m_next2b = CBotDefInt::Compile(p, pStk, true, noskip)))    // compile the next one
-                {
-                    return pStack->Return(inst2, pStk);
-                }
-            }
             inst = static_cast<CBotDefInt*>(inst2);
             goto suite;     // no assignment, variable already created
         }
 
         if (IsOfType(p,  ID_ASS))   // with an assignment?
         {
+            pStk->SetStartError(p->GetStart());
+            if ( IsOfType(p, ID_SEP) )
+            {
+                pStk->SetError(CBotErrBadLeft, p->GetPrev());
+                goto error;
+            }
             if (nullptr == ( inst->m_expr = CBotTwoOpExpr::Compile( p, pStk )))
             {
                 goto error;
@@ -121,15 +114,15 @@ CBotInstr* CBotDefInt::Compile(CBotToken* &p, CBotCStack* pStack, bool cont, boo
                 (static_cast<CBotLeftExprVar*>(inst->m_var))->m_nIdent = CBotVar::NextUniqNum());
             pStack->AddVar(var);    // place it on the stack
         }
-
-        if (IsOfType(p,  ID_COMMA))     // chained several definitions
+suite:
+        if (pStk->IsOk() && IsOfType(p,  ID_COMMA))     // chained several definitions
         {
             if (nullptr != ( inst->m_next2b = CBotDefInt::Compile(p, pStk, true, noskip)))    // compile next one
             {
                 return pStack->Return(inst, pStk);
             }
         }
-suite:
+
         if (noskip || IsOfType(p,  ID_SEP))                    // instruction is completed
         {
             return pStack->Return(inst, pStk);
diff --git a/src/CBot/CBotInstr/CBotDefString.cpp b/src/CBot/CBotInstr/CBotDefString.cpp
index c878a84c..b224a1c0 100644
--- a/src/CBot/CBotInstr/CBotDefString.cpp
+++ b/src/CBot/CBotInstr/CBotDefString.cpp
@@ -75,15 +75,21 @@ CBotInstr* CBotDefString::Compile(CBotToken* &p, CBotCStack* pStack, bool cont,
 
         if (IsOfType(p,  ID_ASS))
         {
+            pStk->SetStartError(p->GetStart());
+            if ( IsOfType(p, ID_SEP) )
+            {
+                pStk->SetError(CBotErrBadLeft, p->GetPrev());
+                goto error;
+            }
             if (nullptr == ( inst->m_expr = CBotTwoOpExpr::Compile( p, pStk )))
             {
                 goto error;
             }
-/*            if (!pStk->GetTypResult().Eq(CBotTypString))            // type compatible ?
+            if (!pStk->GetTypResult().Eq(CBotTypString))            // type compatible ?
             {
                 pStk->SetError(CBotErrBadType1, p->GetStart());
                 goto error;
-            }*/
+            }
         }
 
         CBotVar*    var = CBotVar::Create(*vartoken, CBotTypString);