Show an error message when associativity is assigned to a non-terminal.

src/lalr/ErrorCode.hpp

@@ -25,7 +25,8 @@ enum ErrorCode
     PARSER_ERROR_UNDEFINED_SYMBOL, ///< A grammar symbol is referenced but not defined.
     PARSER_ERROR_UNREFERENCED_SYMBOL, ///< A grammar symbol is defined but not referenced.
     PARSER_ERROR_ERROR_SYMBOL_ON_LEFT_HAND_SIDE, ///< The 'error' symbol has been used on the left hand side of a production.
-    PARSER_ERROR_DUPLICATE_ASSOCIATION_ON_IMPLICIT_TERMINAL ///< Both implicit terminal forms specify associativity and precedence.
+    PARSER_ERROR_DUPLICATE_ASSOCIATION_ON_IMPLICIT_TERMINAL, ///< Both implicit terminal forms specify associativity and precedence.
+    PARSER_ERROR_ASSOCIATIVITY_ASSIGNED_ON_NON_TERMINAL ///< Associativity has been assigned to a non-terminal.
 };
 
 }

src/lalr/GrammarGenerator.cpp

@@ -573,6 +573,10 @@ void GrammarGenerator::calculate_implicit_terminal_symbols()
                 replace_references_to_symbol( non_terminal_symbol, terminal_symbol );
                 i->reset();
             }
+            else if(non_terminal_symbol->associativity() != ASSOCIATE_NULL && non_terminal_symbol->productions().size())
+            {
+                error( non_terminal_symbol->line(), PARSER_ERROR_ASSOCIATIVITY_ASSIGNED_ON_NON_TERMINAL, "associativity has been assigned to a non-terminal: %s",  non_terminal_symbol->identifier().c_str());
+            }
         }
     }