diff --git a/scilab/modules/ast/includes/exps/opexp.hxx b/scilab/modules/ast/includes/exps/opexp.hxx

index ed425c5..43cf7f8 100644

--- a/scilab/modules/ast/includes/exps/opexp.hxx

+++ b/scilab/modules/ast/includes/exps/opexp.hxx

@@ -254,6 +254,7 @@ public:

             case unknown:

                 return L"unknown";

         }

+        return L"";

     }

diff --git a/scilab/modules/ast/src/cpp/analysis/ConstraintManager.cpp b/scilab/modules/ast/src/cpp/analysis/ConstraintManager.cpp

index 72cd0f4..3ef42ab 100644

--- a/scilab/modules/ast/src/cpp/analysis/ConstraintManager.cpp

+++ b/scilab/modules/ast/src/cpp/analysis/ConstraintManager.cpp

@@ -96,6 +96,7 @@ bool ConstraintManager::check(const MPolyConstraintSet & set, const std::vector<

             }

         }

     }

+    return false;

 }

 bool ConstraintManager::check(Kind kind, const std::vector<GVN::Value *> & values)

diff --git a/scilab/modules/ast/src/cpp/analysis/InferenceConstraints.cpp b/scilab/modules/ast/src/cpp/analysis/InferenceConstraints.cpp

index e0853cc..b5d5bfb 100644

--- a/scilab/modules/ast/src/cpp/analysis/InferenceConstraints.cpp

+++ b/scilab/modules/ast/src/cpp/analysis/InferenceConstraints.cpp

@@ -187,6 +187,7 @@ InferenceConstraint::Result MPolyConstraint::check(GVN & gvn, const std::vector<

             }

         }

     }

+    return Result::RESULT_DUNNO;

 }

 MPolyConstraintSet MPolyConstraint::getMPConstraints(const std::vector<GVN::Value *> & values) const