Add validate to symbol_table_baset

This enables use of symbol_table_baset instead of symbol_tablet in many
places.

Author: tautschnig

src/util/journalling_symbol_table.h

@@ -143,6 +143,12 @@ class journalling_symbol_tablet : public symbol_table_baset
   using symbol_table_baset::begin;
   using symbol_table_baset::end;
 
+  void validate(
+    const validation_modet vm = validation_modet::INVARIANT) const override
+  {
+    base_symbol_table.validate(vm);
+  }
+
   const changesett &get_inserted() const
   {
     return inserted;

src/util/symbol_table.h

@@ -118,7 +118,8 @@ class symbol_tablet : public symbol_table_baset
   using symbol_table_baset::end;
 
   /// Check that the symbol table is well-formed
-  void validate(const validation_modet vm = validation_modet::INVARIANT) const;
+  void validate(
+    const validation_modet vm = validation_modet::INVARIANT) const override;
 
   bool operator==(const symbol_tablet &other) const;
 };

src/util/symbol_table_base.h

@@ -239,6 +239,9 @@ class symbol_table_baset
 
   virtual const_iteratort begin() const;
   virtual const_iteratort end() const;
+
+  virtual void
+  validate(const validation_modet vm = validation_modet::INVARIANT) const = 0;
 };
 
 std::ostream &

src/util/symbol_table_builder.h

@@ -88,6 +88,12 @@ class symbol_table_buildert : public symbol_table_baset
   using symbol_table_baset::begin;
   using symbol_table_baset::end;
 
+  void validate(
+    const validation_modet vm = validation_modet::INVARIANT) const override
+  {
+    base_symbol_table.validate(vm);
+  }
+
   /// Try to find the next free identity for the passed-in prefix in
   /// this symbol table.
   /// \remark