Fixed static conversion bugs in the IR section

Former-commit-id: 6b63d4900e

src/ir/expressions/IntegerConstantExpression.cpp

@@ -27,7 +27,7 @@ namespace storm {
             }
             
             double IntegerConstantExpression::getValueAsDouble(std::pair<std::vector<bool>, std::vector<int_fast64_t>> const* variableValues) const {
-                return getValueAsInt(variableValues);
+                return static_cast<double>(getValueAsInt(variableValues));
             }
             
             int_fast64_t IntegerConstantExpression::getValueAsInt(std::pair<std::vector<bool>, std::vector<int_fast64_t>> const* variableValues) const {

src/ir/expressions/IntegerLiteralExpression.cpp

@@ -27,7 +27,7 @@ namespace storm {
             }
             
             double IntegerLiteralExpression::getValueAsDouble(std::pair<std::vector<bool>, std::vector<int_fast64_t>> const* variableValues) const {
-                return value;
+                return static_cast<double>(value);
             }
             
             int_fast64_t IntegerLiteralExpression::getValueAsInt(std::pair<std::vector<bool>, std::vector<int_fast64_t>> const* variableValues) const {

src/ir/expressions/VariableExpression.cpp

@@ -83,7 +83,7 @@ namespace storm {
                 
                 // Because only int variables can deliver a double value, we only need to check them.
                 if (variableValues != nullptr) {
-                    return variableValues->second[globalIndex];
+                    return static_cast<double>(variableValues->second[globalIndex]);
                 } else {
                     throw storm::exceptions::ExpressionEvaluationException() << "Cannot evaluate expression with variable '" << variableName << "' of type double.";
                 }