AMBIGUITY:

AMBIGUITY:

parameter-declaration
 |
 +-- declaration-specifiers
 |    |
 |    +-- type-specifier
 |         |
 |         +-- "int"
 |
 +-- declarator
      |
      +-- direct-declarator
           |
           +-- "("
           |
           +-- declarator
           |    |
           |    +-- direct-declarator
           |         |
           |         +-- typedef-name     <=== NON-STANDARD!
           |              |
           |              +-- "T"
           |
           +-- ")"

parameter-declaration
 |
 +-- declaration-specifiers
 |    |
 |    +-- type-specifier
 |         |
 |         +-- "int"
 |
 +-- abstract-declarator
      |
      +-- direct-abstract-declarator
           |
           +-- "("
           |
           +-- parameter-type-list
           |    |
	   | 	+-- parameter-list
	   |	     |
	   |	     +-- parameter-declaration
	   |	          |
	   |		  +-- declaration-specifiers
	   |		       |
	   |		       +-- type-specifier
	   |		            |
	   |		   	    +-- typedef-name
	   |			         |
	   |				 +-- "T"
	   |
       	   +-- ")"

GCC:

typedef int T;

void foo()
{
    typedef int (*T2int)(T); // (T ->* int)
    typedef int (*fn)(int (T)); // interpreted as ((T ->* int) ->* int)
    //                     |
    //                     +-- so this is a parameter-type-list, not a declaration
    T2int g;
    fn f;

    (*f)(g);
}

void bar()
{
    float (T); // <-- this is a valid declarator
}


POSSIBLE SOLUTION:
* change the production:
    parameter-declaration --> declaration-specifiers declarator
  to
    parameter-declaration --> declaration-specifiers declarator-paren-tn
* declarator-paren-tn doesn't allow parenthesized typedef-names:
  o declarator-paren-tn --> direct-declarator-paren-tn
  o direct-declarator-paren-tn --> "(" declarator-tn ")"
* XXX: can we allow direct-declarator-tn --> "(" declarator ")" ???
       instead of direct-declarator-tn --> "(" declarator-tn ")" ???


CONTEXT:
 
ParameterDeclaration --> DeclarationSpecifiers . Declarator<AnyIdentifier>
    Declarator<AnyIdentifier> --> . DirectDeclarator<AnyIdentifier>
        DirectDeclarator<AnyIdentifier> --> "(" . Declarator<AnyIdentifier> ")"

ParameterDeclaration --> DeclarationSpecifiers . AbstractDeclarator
    AbstractDeclarator --> . DirectAbstractDeclarator
        DirectAbstractDeclarator --> "(" . ParameterTypeList ")"

typedef int (*fn)(int (int));






16	!PushFormalsContext	=	()

...

State 324
	!CacheDeclaratorTypedefName -> TYPEDEF_NAME . 

	long					reduce	26
	O_BRACKET					reduce	26
	union					reduce	26
	double					reduce	26
	int					reduce	26
	COMMA					reduce	26
	_Bool					reduce	26
	enum					reduce	26
	unsigned					reduce	26
	inline					reduce	26
	short					reduce	26
	const					reduce	26
	typedef					reduce	26
	register					reduce	26
	C_PAREN					reduce	26
	O_BRACE					reduce	26
	float					reduce	26
	SEMI_COLON					reduce	26
	void					reduce	26
	char					reduce	26
	O_PAREN					reduce	26
	volatile					reduce	26
	static					reduce	26
	auto					reduce	26
	COLON					reduce	26
	restrict					reduce	26
	struct					reduce	26
	_Complex					reduce	26
	=					reduce	26
	signed					reduce	26
	extern					reduce	26
	TYPEDEF_NAME					reduce	26

...

State 642
	DirectDeclarator -> O_PAREN . Declarator C_PAREN 
	DirectAbstractDeclarator -> O_PAREN . AbstractDeclarator C_PAREN 
	DirectAbstractDeclarator -> O_PAREN . !PushFormalsContext !PushScope ParameterTypeList !PopScope !PopContext C_PAREN 
	DirectAbstractDeclarator -> O_PAREN . !PushFormalsContext !PushScope !PopScope !PopContext C_PAREN 

	long					reduce	16
	AbstractDeclarator					goto	296
	O_BRACKET					shift	212
	union					reduce	16
	double					reduce	16
	int					reduce	16
	DirectDeclarator					goto	322
	IDENTIFIER					shift	315
	_Bool					reduce	16
	unsigned					reduce	16
	inline					reduce	16
	short					reduce	16
	const					reduce	16
	typedef					reduce	16
	!CacheDeclaratorIdentifier					goto	319
	!PushFormalsContext					goto	295
	extern					reduce	16
	Declarator					goto	400
	C_PAREN					reduce	16
	enum					reduce	16
	*					shift	210
	float					reduce	16
	Pointer					goto	640
	void					reduce	16
	char					reduce	16
	auto					reduce	16
	DirectAbstractDeclarator					goto	209
	volatile					reduce	16
	static					reduce	16
	restrict					reduce	16
	struct					reduce	16
	_Complex					reduce	16
	register					reduce	16
	signed					reduce	16
	O_PAREN					shift	642
begin conflict:
	TYPEDEF_NAME					shift	324
	TYPEDEF_NAME					reduce	16
end conflict
	!CacheDeclaratorTypedefName					goto	320