diff --git a/apps/shared/store_context.cpp b/apps/shared/store_context.cpp
index 533a7a3e9..804fff700 100644
--- a/apps/shared/store_context.cpp
+++ b/apps/shared/store_context.cpp
@@ -7,7 +7,7 @@ using namespace Poincare;
 
 namespace Shared {
 
-void StoreContext::setExpressionForSymbol(const Expression & expression, const Symbol & symbol, Context & context) {
+void StoreContext::setExpressionForSymbol(const Expression & expression, const SymbolAbstract & symbol, Context & context) {
   m_parentContext->setExpressionForSymbol(expression, symbol, context);
 }
 
diff --git a/apps/shared/store_context.h b/apps/shared/store_context.h
index 9c1eaeb7e..79db7930e 100644
--- a/apps/shared/store_context.h
+++ b/apps/shared/store_context.h
@@ -19,7 +19,7 @@ public:
   {}
   void setParentContext(Poincare::Context * parentContext) { m_parentContext = parentContext; }
   void setSeriesPairIndex(int j) { m_seriesPairIndex = j; }
-  void setExpressionForSymbol(const Poincare::Expression & expression, const Poincare::Symbol & symbol, Poincare::Context & context) override;
+  void setExpressionForSymbol(const Poincare::Expression & expression, const Poincare::SymbolAbstract & symbol, Poincare::Context & context) override;
 protected:
   Shared::DoublePairStore * m_store;
   int m_seriesPairIndex;
diff --git a/poincare/include/poincare/context.h b/poincare/include/poincare/context.h
index 41cb9a0ad..f538551d9 100644
--- a/poincare/include/poincare/context.h
+++ b/poincare/include/poincare/context.h
@@ -10,7 +10,7 @@ class Symbol; //TODO remove?
 class Context {
 public:
   virtual const Expression expressionForSymbol(const SymbolAbstract & symbol) = 0;
-  virtual void setExpressionForSymbol(const Expression & expression, const Symbol & symbol, Context & context) = 0;
+  virtual void setExpressionForSymbol(const Expression & expression, const SymbolAbstract & symbol, Context & context) = 0;
 };
 
 }
diff --git a/poincare/include/poincare/expression.h b/poincare/include/poincare/expression.h
index 72fe46b18..b46b7175f 100644
--- a/poincare/include/poincare/expression.h
+++ b/poincare/include/poincare/expression.h
@@ -13,7 +13,7 @@
 namespace Poincare {
 
 class Context;
-class Symbol;
+class SymbolAbstract;
 
 class Expression : public TreeHandle {
   friend class AbsoluteValue;
@@ -148,7 +148,7 @@ public:
   static constexpr int k_maxPolynomialDegree = 2;
   static constexpr int k_maxNumberOfPolynomialCoefficients = k_maxPolynomialDegree+1;
   int getPolynomialReducedCoefficients(const char * symbolName, Expression coefficients[], Context & context, Preferences::AngleUnit angleUnit) const;
-  Expression replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression) { return node()->replaceSymbolWithExpression(symbol, expression); }
+  Expression replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression) { return node()->replaceSymbolWithExpression(symbol, expression); }
 
   /* Comparison */
   /* isIdenticalTo is the "easy" equality, it returns true if both trees have
@@ -236,7 +236,7 @@ private:
   template<typename U> Evaluation<U> approximateToEvaluation(Context& context, Preferences::AngleUnit angleUnit) const;
 
   /* Properties */
-  Expression defaultReplaceSymbolWithExpression(const Symbol & symbol, const Expression expression);
+  Expression defaultReplaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression expression);
   int defaultGetPolynomialCoefficients(Context & context, const char * symbol, Expression expression[]) const;
 
   /* Expression roots/extrema solver*/
diff --git a/poincare/include/poincare/expression_node.h b/poincare/include/poincare/expression_node.h
index 832a42d62..bc036647f 100644
--- a/poincare/include/poincare/expression_node.h
+++ b/poincare/include/poincare/expression_node.h
@@ -12,7 +12,7 @@ namespace Poincare {
 /* Methods preceded by '*!*' interfere with the expression pool, which can make
  * 'this' outdated. They should only be called in a wrapper on Expression. */
 
-class Symbol;
+class SymbolAbstract;
 
 class ExpressionNode : public TreeNode {
   friend class AdditionNode;
@@ -101,7 +101,7 @@ public:
   };
   virtual Sign sign() const { return Sign::Unknown; }
   virtual bool isNumber() const { return false; }
-  /*!*/ virtual Expression replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression);
+  /*!*/ virtual Expression replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression);
   /*!*/ virtual Expression setSign(Sign s, Context & context, Preferences::AngleUnit angleUnit);
   virtual int polynomialDegree(Context & context, const char * symbolName) const;
   /*!*/ virtual int getPolynomialCoefficients(Context & context, const char * symbolName, Expression coefficients[]) const;
diff --git a/poincare/include/poincare/function.h b/poincare/include/poincare/function.h
index a19a1ee09..9969e1243 100644
--- a/poincare/include/poincare/function.h
+++ b/poincare/include/poincare/function.h
@@ -24,7 +24,7 @@ public:
   // Properties
   Type type() const override { return Type::Function; }
   Sign sign() const override { return Sign::Unknown; }
-  Expression replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression) override;
+  Expression replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression) override;
   int polynomialDegree(Context & context, const char * symbolName) const override;
   int getPolynomialCoefficients(Context & context, const char * symbolName, Expression coefficients[]) const override;
   int getVariables(Context & context, isVariableTest isVariable, char * variables, int maxSizeVariable) const override;
@@ -53,7 +53,7 @@ public:
     replaceChildAtIndexInPlace(0, operand);
   }
 
-  Expression replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression);
+  Expression replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression);
   Expression shallowReduce(Context & context, Preferences::AngleUnit angleUnit, bool replaceSymbols = true);
 };
 
diff --git a/poincare/include/poincare/global_context.h b/poincare/include/poincare/global_context.h
index a0eefef1b..9a802fe62 100644
--- a/poincare/include/poincare/global_context.h
+++ b/poincare/include/poincare/global_context.h
@@ -20,7 +20,7 @@ public:
   /* The expression recorded in global context is already a expression.
    * Otherwise, we would need the context and the angle unit to evaluate it */
   const Expression expressionForSymbol(const SymbolAbstract & symbol) override;
-  void setExpressionForSymbol(const Expression & expression, const Symbol & symbol, Context & context) override;
+  void setExpressionForSymbol(const Expression & expression, const SymbolAbstract & symbol, Context & context) override;
   static Ion::Storage::Record RecordWithName(const char * name);
   static bool storageMemoryFull();
   //TODO static constexpr uint16_t k_maxNumberOfSequences = 10;
diff --git a/poincare/include/poincare/store.h b/poincare/include/poincare/store.h
index 8a9703f4c..eeb531626 100644
--- a/poincare/include/poincare/store.h
+++ b/poincare/include/poincare/store.h
@@ -2,7 +2,7 @@
 #define POINCARE_STORE_H
 
 #include <poincare/expression.h>
-#include <poincare/symbol.h>
+#include <poincare/symbol_abstract.h>
 #include <poincare/layout_helper.h>
 #include <poincare/evaluation.h>
 
@@ -39,16 +39,16 @@ private:
 class Store final : public Expression {
 public:
   Store(const StoreNode * n) : Expression(n) {}
-  Store(Expression value, Symbol symbol) : Expression(TreePool::sharedPool()->createTreeNode<StoreNode>()) {
+  Store(Expression value, SymbolAbstract symbol) : Expression(TreePool::sharedPool()->createTreeNode<StoreNode>()) {
     replaceChildAtIndexInPlace(0, value);
     replaceChildAtIndexInPlace(1, symbol);
   }
 
   // Store
-  const Symbol symbol() const {
+  const SymbolAbstract symbol() const {
     assert(childAtIndex(1).type() == ExpressionNode::Type::Symbol
         || childAtIndex(1).type() == ExpressionNode::Type::Function);
-    return childAtIndex(1).convert<const Symbol>();
+    return childAtIndex(1).convert<const SymbolAbstract>();
   }
   const Expression value() const {
     return childAtIndex(0);
diff --git a/poincare/include/poincare/symbol.h b/poincare/include/poincare/symbol.h
index 201609acb..a3aab4120 100644
--- a/poincare/include/poincare/symbol.h
+++ b/poincare/include/poincare/symbol.h
@@ -25,7 +25,7 @@ public:
   // Expression Properties
   Type type() const override { return Type::Symbol; }
   Sign sign() const override;
-  Expression replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression) override;
+  Expression replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression) override;
   int polynomialDegree(Context & context, const char * symbolName) const override;
   int getPolynomialCoefficients(Context & context, const char * symbolName, Expression coefficients[]) const override;
   int getVariables(Context & context, isVariableTest isVariable, char * variables, int maxSizeVariable) const override;
@@ -78,7 +78,7 @@ public:
 
   // Expression
   Expression shallowReduce(Context & context, Preferences::AngleUnit angleUnit, bool replaceSymbols = true);
-  Expression replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression);
+  Expression replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression);
   int getPolynomialCoefficients(Context & context, const char * symbolName, Expression coefficients[]) const;
 private:
   SymbolNode * node() const { return static_cast<SymbolNode *>(Expression::node()); }
diff --git a/poincare/include/poincare/variable_context.h b/poincare/include/poincare/variable_context.h
index d4d8da0aa..26c1d58a1 100644
--- a/poincare/include/poincare/variable_context.h
+++ b/poincare/include/poincare/variable_context.h
@@ -13,7 +13,7 @@ public:
   void setApproximationForVariable(T value);
 
   // Context
-  void setExpressionForSymbol(const Expression & expression, const Symbol & symbol, Context & context) override;
+  void setExpressionForSymbol(const Expression & expression, const SymbolAbstract & symbol, Context & context) override;
   const Expression expressionForSymbol(const SymbolAbstract & symbol) override;
 
 private:
diff --git a/poincare/src/expression.cpp b/poincare/src/expression.cpp
index ebb4e00a4..3e20b5fc0 100644
--- a/poincare/src/expression.cpp
+++ b/poincare/src/expression.cpp
@@ -3,6 +3,7 @@
 #include <poincare/rational.h>
 #include <poincare/opposite.h>
 #include <poincare/undefined.h>
+#include <poincare/symbol_abstract.h>
 #include <poincare/symbol.h>
 #include <poincare/variable_context.h>
 #include <ion.h>
@@ -218,7 +219,7 @@ Evaluation<U> Expression::approximateToEvaluation(Context& context, Preferences:
   return node()->approximate(U(), context, angleUnit);
 }
 
-Expression Expression::defaultReplaceSymbolWithExpression(const Symbol & symbol, const Expression expression) {
+Expression Expression::defaultReplaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression expression) {
   for (int i = 0; i < numberOfChildren(); i++) {
     childAtIndex(i).replaceSymbolWithExpression(symbol, expression);
   }
diff --git a/poincare/src/expression_node.cpp b/poincare/src/expression_node.cpp
index 8eb5635da..8876cb6d1 100644
--- a/poincare/src/expression_node.cpp
+++ b/poincare/src/expression_node.cpp
@@ -5,7 +5,7 @@
 
 namespace Poincare {
 
-Expression ExpressionNode::replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression) {
+Expression ExpressionNode::replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression) {
   return Expression(this).defaultReplaceSymbolWithExpression(symbol, expression);
 }
 
diff --git a/poincare/src/function.cpp b/poincare/src/function.cpp
index 8fd0241d4..15b898120 100644
--- a/poincare/src/function.cpp
+++ b/poincare/src/function.cpp
@@ -29,7 +29,7 @@ size_t FunctionNode::size() const {
   return NodeSize(strlen(m_name));
 }
 
-Expression FunctionNode::replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression) {
+Expression FunctionNode::replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression) {
   return Function(this).replaceSymbolWithExpression(symbol, expression);
 }
 
@@ -113,7 +113,7 @@ Function::Function(const char * name) :
   static_cast<FunctionNode *>(Expression::node())->setName(name, strlen(name));
 }
 
-Expression Function::replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression) {
+Expression Function::replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression) {
   // Replace the symbol in the child
   childAtIndex(0).replaceSymbolWithExpression(symbol, expression);
   if (symbol.type() == ExpressionNode::Type::Function && strcmp(name(), symbol.name()) == 0) {
diff --git a/poincare/src/global_context.cpp b/poincare/src/global_context.cpp
index 8640562fe..c09bb6915 100644
--- a/poincare/src/global_context.cpp
+++ b/poincare/src/global_context.cpp
@@ -37,7 +37,7 @@ const Expression GlobalContext::expressionForSymbol(const SymbolAbstract & symbo
   return Expression::ExpressionFromRecord(RecordWithName(symbol.name()));
 }
 
-void GlobalContext::setExpressionForSymbol(const Expression & expression, const Symbol & symbol, Context & context) {
+void GlobalContext::setExpressionForSymbol(const Expression & expression, const SymbolAbstract & symbol, Context & context) {
   sStorageMemoryFull = false;
   /* If the new expression contains the symbol, replace it because it will be
    * destroyed afterwards (to be able to do A+2->A) */
diff --git a/poincare/src/store.cpp b/poincare/src/store.cpp
index 8697eeecc..a4497001f 100644
--- a/poincare/src/store.cpp
+++ b/poincare/src/store.cpp
@@ -1,16 +1,16 @@
+#include <poincare/store.h>
+#include <poincare/char_layout.h>
+#include <poincare/context.h>
+#include <poincare/complex.h>
+#include <poincare/horizontal_layout.h>
+#include <poincare/serialization_helper.h>
+#include <poincare/symbol.h>
+#include <ion.h>
 extern "C" {
 #include <assert.h>
 #include <stdlib.h>
 #include <math.h>
 }
-#include <poincare/store.h>
-#include <ion.h>
-#include <poincare/context.h>
-#include <poincare/serialization_helper.h>
-#include <poincare/complex.h>
-#include <poincare/char_layout.h>
-#include <poincare/horizontal_layout.h>
-
 
 namespace Poincare {
 
diff --git a/poincare/src/symbol.cpp b/poincare/src/symbol.cpp
index fcee778f9..bbbe13e62 100644
--- a/poincare/src/symbol.cpp
+++ b/poincare/src/symbol.cpp
@@ -47,7 +47,7 @@ ExpressionNode::Sign SymbolNode::sign() const {
   return Sign::Unknown;
 }
 
-Expression SymbolNode::replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression) {
+Expression SymbolNode::replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression) {
   return Symbol(this).replaceSymbolWithExpression(symbol, expression);
 }
 
@@ -210,7 +210,7 @@ Expression Symbol::shallowReduce(Context & context, Preferences::AngleUnit angle
   return *this;
 }
 
-Expression Symbol::replaceSymbolWithExpression(const Symbol & symbol, const Expression & expression) {
+Expression Symbol::replaceSymbolWithExpression(const SymbolAbstract & symbol, const Expression & expression) {
   if (symbol.type() == ExpressionNode::Type::Symbol && strcmp(name(), symbol.name()) == 0) {
     Expression value = expression.clone();
     Expression p = parent();
diff --git a/poincare/src/variable_context.cpp b/poincare/src/variable_context.cpp
index 65ca57eec..448fead7b 100644
--- a/poincare/src/variable_context.cpp
+++ b/poincare/src/variable_context.cpp
@@ -18,7 +18,7 @@ void VariableContext::setApproximationForVariable(T value) {
   m_value = Float<T>(value);
 }
 
-void VariableContext::setExpressionForSymbol(const Expression & expression, const Symbol & symbol, Context & context) {
+void VariableContext::setExpressionForSymbol(const Expression & expression, const SymbolAbstract & symbol, Context & context) {
   if (strcmp(symbol.name(), m_name) == 0) {
     if (expression.isUninitialized()) {
       return;