diff --git a/src/flatzinc/parser.cc b/src/flatzinc/parser.cc
index a5d34b9b07..33fce9d80d 100644
--- a/src/flatzinc/parser.cc
+++ b/src/flatzinc/parser.cc
@@ -18,6 +18,28 @@ extern void yyset_extra (void* user_defined ,void* yyscanner );
 extern void yyerror(void* parm, const char *str);
 
 namespace operations_research {
+// ----- Misc -----
+bool HasDomainAnnotation(AST::Node* const annotations) {
+  if (annotations != NULL) {
+    return annotations->hasAtom("domain");
+  }
+  return false;
+}
+
+bool HasDefineAnnotation(AST::Node* const annotations) {
+  if (annotations != NULL) {
+    if (annotations->isArray()) {
+      AST::Array* const ann_array = annotations->getArray();
+      if (ann_array->a[0]->isCall("defines_var")) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+// ----- Parser State -----
+
 ParserState::~ParserState() {
   STLDeleteElements(&int_variables_);
   STLDeleteElements(&bool_variables_);
@@ -79,13 +101,6 @@ AST::Node* ParserState::FindTarget(AST::Node* const annotations) const {
   return NULL;
 }
 
-bool HasDomainAnnotation(AST::Node* const annotations) {
-  if (annotations != NULL) {
-    return annotations->hasAtom("domain");
-  }
-  return false;
-}
-
 void ParserState::CollectRequired(AST::Array* const args,
                                   const NodeSet& candidates,
                                   NodeSet* const require) const {
@@ -1040,7 +1055,7 @@ bool ParserState::PresolveOneConstraint(CtSpec* const spec) {
         break;
       }
     }
-    if (!one_positive) {
+    if (!one_positive && !HasDefineAnnotation(spec->annotations())) {
       VLOG(1) << "  - presolve:  transform all negative int_lin_eq into "
               << "int_lin_eq in " << spec->DebugString();
 
diff --git a/src/flatzinc/registry.cc b/src/flatzinc/registry.cc
index 244882b16f..994076a19f 100644
--- a/src/flatzinc/registry.cc
+++ b/src/flatzinc/registry.cc
@@ -433,7 +433,6 @@ void p_int_lin_eq_reif(FlatZincModel* const model, CtSpec* const spec) {
   const int size = array_coefficients->a.size();
   CHECK_EQ(size, array_variables->a.size());
   std::vector<int> coefficients(size);
-  std::vector<IntVar*> variables(size);
 
   int positive = 0;
   int negative = 0;
@@ -466,12 +465,12 @@ void p_int_lin_eq_reif(FlatZincModel* const model, CtSpec* const spec) {
       std::vector<IntVar*> neg_vars;
       std::vector<int64> neg_coeffs;
       for (int i = 0; i < size; ++i) {
-        variables[i] = model->GetIntExpr(array_variables->a[i])->Var();
+        IntVar* const var = model->GetIntExpr(array_variables->a[i])->Var();
         const int64 coeff = coefficients[i];
         if (coeff > 0) {
-          pos = solver->MakeProd(variables[i], coeff);
+          pos = solver->MakeProd(var, coeff);
         } else if (coeff < 0) {
-          neg_vars.push_back(variables[i]);
+          neg_vars.push_back(var);
           neg_coeffs.push_back(-coeff);
         }
       }
@@ -499,7 +498,7 @@ void p_int_lin_eq_reif(FlatZincModel* const model, CtSpec* const spec) {
         const int64 coeff = coefficients[i];
         IntExpr* const expr = model->GetIntExpr(array_variables->a[i]);
         if (coeff < 0) {
-          neg = solver->MakeProd(variables[i], -coeff);
+          neg = solver->MakeProd(expr, -coeff);
         } else if (coeff > 0) {
           pos_exprs.push_back(solver->MakeProd(expr, coeff));
         }
@@ -510,11 +509,11 @@ void p_int_lin_eq_reif(FlatZincModel* const model, CtSpec* const spec) {
       std::vector<int64> pos_coeffs;
       for (int i = 0; i < size; ++i) {
         const int64 coeff = coefficients[i];
-        variables[i] = model->GetIntExpr(array_variables->a[i])->Var();
+        IntVar* const var = model->GetIntExpr(array_variables->a[i])->Var();
         if (coeff < 0) {
-          neg = solver->MakeProd(variables[i], -coeff);
+          neg = solver->MakeProd(var, -coeff);
         } else if (coeff > 0) {
-          pos_vars.push_back(variables[i]);
+          pos_vars.push_back(var);
           pos_coeffs.push_back(coeff);
         }
       }
@@ -534,6 +533,7 @@ void p_int_lin_eq_reif(FlatZincModel* const model, CtSpec* const spec) {
       solver->AddConstraint(ct);
     }
   } else {
+    std::vector<IntVar*> variables(size);
     for (int i = 0; i < size; ++i) {
       coefficients[i] = array_coefficients->a[i]->getInt();
       variables[i] = model->GetIntExpr(array_variables->a[i])->Var();