diff --git a/src/bdd/dsd/dsdProc.c b/src/bdd/dsd/dsdProc.c
index bcc3102cf..8c775e8b9 100644
--- a/src/bdd/dsd/dsdProc.c
+++ b/src/bdd/dsd/dsdProc.c
@@ -873,7 +873,7 @@ if ( s_Show )
                         for ( m = 0; m < pLR->nDecs; m++ )
                             if ( pLR->pDecs[m] != pLastDiffL )
                                  pCommon[nCommon++] = pLR->pDecs[m];
-                        assert( nCommon = pLR->nDecs-1 );
+                        assert( nCommon == pLR->nDecs-1 );
                     }
                 }
                 else
diff --git a/src/proof/live/ltl_parser.c b/src/proof/live/ltl_parser.c
index 36d109ccd..646e8f48c 100644
--- a/src/proof/live/ltl_parser.c
+++ b/src/proof/live/ltl_parser.c
@@ -519,7 +519,7 @@ void populateAigPointerUnitGF( Aig_Man_t *pAigNew, ltlNode *topASTNode, Vec_Ptr_
             return;
         case GLOBALLY:
             nextNode = topASTNode->left;
-            assert( nextNode->type = EVENTUALLY );
+            assert( nextNode->type == EVENTUALLY );
             nextToNextNode = nextNode->left;
             if( nextToNextNode->type == BOOL )
             {
diff --git a/src/proof/ssc/sscUtil.c b/src/proof/ssc/sscUtil.c
index db7f772bf..c88e0220e 100644
--- a/src/proof/ssc/sscUtil.c
+++ b/src/proof/ssc/sscUtil.c
@@ -96,7 +96,7 @@ Gia_Man_t * Gia_ManDropContained( Gia_Man_t * p )
             Vec_IntWriteEntry( vLits, i, ConstLit ); // const1 SAT var is always true
         else 
         {
-            assert( status = l_True );
+            assert( status == l_True );
             Vec_IntPush( vKeep, i );
         }
     }