diff --git a/engine/compiler.c b/engine/compiler.c
index 84db7f3..d5b5e1d 100644
--- a/engine/compiler.c
+++ b/engine/compiler.c
@@ -4219,9 +4219,9 @@ done:
 static sxi32 GenStateCompileClass(ph7_gen_state *pGen, sxi32 iFlags) {
 	sxu32 nLine = pGen->pIn->nLine;
 	ph7_class *pClass, *pBase;
+	ph7_class_info *pClassInfo;
 	SyToken *pEnd, *pTmp;
 	sxi32 iProtection;
-	SySet aInterfaces;
 	sxi32 iAttrflags;
 	SyString *pName;
 	sxi32 nKwrd;
@@ -4253,8 +4253,12 @@ static sxi32 GenStateCompileClass(ph7_gen_state *pGen, sxi32 iFlags) {
 		PH7_GenCompileError(pGen, E_ERROR, nLine, "Fatal, PH7 is running out of memory");
 		return SXERR_ABORT;
 	}
-	/* implemented interfaces container */
-	SySetInit(&aInterfaces, &pGen->pVm->sAllocator, sizeof(ph7_class *));
+	/* Obtain a raw class inheritance storage */
+	pClassInfo = PH7_NewClassInfo(pGen->pVm, pName);
+	if(pClassInfo == 0) {
+		PH7_GenCompileError(pGen, E_ERROR, nLine, "Fatal, PH7 is running out of memory");
+		return SXERR_ABORT;
+	}
 	/* Assume a standalone class */
 	pBase = 0;
 	if(pGen->pIn < pGen->pEnd  && (pGen->pIn->nType & PH7_TK_KEYWORD)) {
@@ -4280,7 +4284,7 @@ static sxi32 GenStateCompileClass(ph7_gen_state *pGen, sxi32 iFlags) {
 				SyStrncpy(pName, pGen->pIn->sData.zString, pGen->pIn->sData.nByte);
 				SyStringInitFromBuf(&pBaseName, pName, SyStrlen(pName));
 				/* Register inherited class */
-				SySetPut(&pClass->sExtends, (const void *)&pBaseName);
+				SySetPut(&pClassInfo->sExtends, (const void *)&pBaseName);
 				/* Advance the stream cursor */
 				pGen->pIn++;
 				if(pGen->pIn >= pGen->pEnd || (pGen->pIn->nType & PH7_TK_COMMA) == 0) {
@@ -4314,7 +4318,7 @@ static sxi32 GenStateCompileClass(ph7_gen_state *pGen, sxi32 iFlags) {
 				SyStrncpy(pName, pGen->pIn->sData.zString, pGen->pIn->sData.nByte);
 				SyStringInitFromBuf(&pIntName, pName, SyStrlen(pName));
 				/* Register inherited class */
-				SySetPut(&pClass->sImplements, (const void *)&pIntName);
+				SySetPut(&pClassInfo->sImplements, (const void *)&pIntName);
 				/* Advance the stream cursor */
 				pGen->pIn++;
 				if(pGen->pIn >= pGen->pEnd || (pGen->pIn->nType & PH7_TK_COMMA) == 0) {
@@ -4565,7 +4569,7 @@ static sxi32 GenStateCompileClass(ph7_gen_state *pGen, sxi32 iFlags) {
 	rc = PH7_VmInstallClass(pGen->pVm, pClass);
 	if(iP1 || iP2) {
 		/* Emit the CLASS_INIT instruction only if there is such a need */
-		PH7_VmEmitInstr(pGen->pVm, PH7_OP_CLASS_INIT, iP1, iP2, pClass, 0);
+		PH7_VmEmitInstr(pGen->pVm, PH7_OP_CLASS_INIT, iP1, iP2, pClassInfo, 0);
 	}
 	if(rc != SXRET_OK) {
 		PH7_GenCompileError(pGen, E_ERROR, nLine, "Fatal, PH7 is running out of memory");
diff --git a/engine/oop.c b/engine/oop.c
index 478edc2..6762b0f 100644
--- a/engine/oop.c
+++ b/engine/oop.c
@@ -15,6 +15,33 @@
 /*
  * This file implement an Object Oriented (OO) subsystem for the PH7 engine.
  */
+/*
+ * Create an empty class inheritance storage.
+ * Return a pointer to a storage (ph7_class_info instance) on success. NULL otherwise.
+ */
+PH7_PRIVATE ph7_class_info *PH7_NewClassInfo(ph7_vm *pVm, const SyString *pName) {
+	ph7_class_info *pClassInfo;
+	char *zName;
+	/* Allocate a new instance */
+	pClassInfo = (ph7_class_info *)SyMemBackendPoolAlloc(&pVm->sAllocator, sizeof(ph7_class_info));
+	if(pClassInfo == 0) {
+		return 0;
+	}
+	/* Zero the structure */
+	SyZero(pClassInfo, sizeof(ph7_class_info));
+	/* Duplicate class name */
+	zName = SyMemBackendStrDup(&pVm->sAllocator, pName->zString, pName->nByte);
+	if(zName == 0) {
+		SyMemBackendPoolFree(&pVm->sAllocator, pClassInfo);
+		return 0;
+	}
+	/* Initialize the class information storage */
+	SyStringInitFromBuf(&pClassInfo->sName, zName, pName->nByte);
+	SySetInit(&pClassInfo->sExtends, &pVm->sAllocator, sizeof(SyString));
+	SySetInit(&pClassInfo->sImplements, &pVm->sAllocator, sizeof(SyString));
+	/* All done */
+	return pClassInfo;
+}
 /*
  * Create an empty class.
  * Return a pointer to a raw class (ph7_class instance) on success. NULL otherwise.
diff --git a/engine/vm.c b/engine/vm.c
index df1ee90..f3b1751 100644
--- a/engine/vm.c
+++ b/engine/vm.c
@@ -4515,7 +4515,7 @@ static sxi32 VmByteCodeExec(
 			 */
 			case PH7_OP_CLASS_INIT:
 				{
-					ph7_class *pClassInfo = (ph7_class *)pInstr->p3;
+					ph7_class_info *pClassInfo = (ph7_class_info *)pInstr->p3;
 					ph7_class *pClass = PH7_VmExtractClass(pVm, pClassInfo->sName.zString, pClassInfo->sName.nByte, FALSE, 0);
 					ph7_class *pBase = 0;
 					if(pInstr->iP1) {
diff --git a/include/ph7int.h b/include/ph7int.h
index 215d53f..8160e27 100644
--- a/include/ph7int.h
+++ b/include/ph7int.h
@@ -38,7 +38,9 @@ typedef struct ph7_foreach_info   ph7_foreach_info;
 typedef struct ph7_foreach_step   ph7_foreach_step;
 typedef struct ph7_hashmap_node   ph7_hashmap_node;
 typedef struct ph7_hashmap        ph7_hashmap;
+typedef struct ph7_class_info     ph7_class_info;
 typedef struct ph7_class          ph7_class;
+
 /* Symisc Standard types */
 #if !defined(SYMISC_STD_TYPES)
 	#define SYMISC_STD_TYPES
@@ -1021,6 +1023,15 @@ struct ph7_builtin_constant {
 /* Forward reference */
 typedef struct ph7_class_method ph7_class_method;
 typedef struct ph7_class_attr   ph7_class_attr;
+/*
+ * Information about class/interface inheritance and interface implementation
+ * is stored in an instance of the following structure. 
+ */
+struct ph7_class_info {
+	SyString sName;       /* Class full qualified name */
+	SySet sExtends;       /* List of inherited classes / interfaces */
+	SySet sImplements;    /* List of implemented interfaces */
+};
 /*
  * Each class is parsed out and stored in an instance of the following structure.
  * PH7 introduced powerfull extensions to the PHP 5 OO subsystems.
@@ -1693,6 +1704,7 @@ PH7_PRIVATE sxi32 PH7_StripTagsFromString(ph7_context *pCtx, const char *zIn, in
 PH7_PRIVATE sxi32 PH7_ParseIniString(ph7_context *pCtx, const char *zIn, sxu32 nByte, int bProcessSection);
 #endif
 /* oo.c function prototypes */
+PH7_PRIVATE ph7_class_info *PH7_NewClassInfo(ph7_vm *pVm, const SyString *pName);
 PH7_PRIVATE ph7_class *PH7_NewRawClass(ph7_vm *pVm, const SyString *pName, sxu32 nLine);
 PH7_PRIVATE ph7_class_attr *PH7_NewClassAttr(ph7_vm *pVm, const SyString *pName, sxu32 nLine, sxi32 iProtection, sxi32 iFlags);
 PH7_PRIVATE ph7_class_method *PH7_NewClassMethod(ph7_vm *pVm, ph7_class *pClass, const SyString *pName, sxu32 nLine,
@@ -1701,7 +1713,7 @@ PH7_PRIVATE ph7_class_method *PH7_ClassExtractMethod(ph7_class *pClass, const ch
 PH7_PRIVATE ph7_class_attr    *PH7_ClassExtractAttribute(ph7_class *pClass, const char *zName, sxu32 nByte);
 PH7_PRIVATE sxi32 PH7_ClassInstallAttr(ph7_class *pClass, ph7_class_attr *pAttr);
 PH7_PRIVATE sxi32 PH7_ClassInstallMethod(ph7_class *pClass, ph7_class_method *pMeth);
-PH7_PRIVATE sxi32 PH7_ClassInherit(ph7_class *pSub, ph7_class *pBase);
+PH7_PRIVATE sxi32 PH7_ClassInherit(ph7_vm *pVm, ph7_class *pSub, ph7_class *pBase);
 PH7_PRIVATE sxi32 PH7_ClassInterfaceInherit(ph7_class *pSub, ph7_class *pBase);
 PH7_PRIVATE sxi32 PH7_ClassImplement(ph7_class *pMain, ph7_class *pInterface);
 PH7_PRIVATE ph7_class_instance *PH7_NewClassInstance(ph7_vm *pVm, ph7_class *pClass);