bug: Incorrect parsing of old style function returning pointer type

[hjjandy]

Did you check existing issues?

• I have read all the tree-sitter docs if it relates to using the parser
• I have searched the existing issues of tree-sitter-c

Tree-Sitter CLI Version, if relevant (output of tree-sitter --version)

Playground, tree-sitter-c 0.23.4 (Python binding)

Describe the bug

An old style function that returns pointer types will be not parsed as a function_definition. Instead, it is split into a sequence of declarations and a compound_statement. The first parameter declaration is treated as part of the function declarator, and if it is of pointer type, an ERROR node emits.

Steps To Reproduce/Bad Parse Tree

In the Playground, parsing the following code:

    int* func(a)
    int* a;
    {   
    }

Expected Behavior/Parse Tree

The erroneous parse tree is as follows:

[translation_unit](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 4] - [6, 0]
  [declaration](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 4] - [2, 11]
    type: [primitive_type](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 4] - [1, 7]
    declarator: [pointer_declarator](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 7] - [2, 10]
      [*](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 7] - [1, 8]
      declarator: [function_declarator](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 9] - [2, 10]
        declarator: [identifier](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 9] - [1, 13]
        parameters: [parameter_list](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 13] - [1, 16]
          [(](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 13] - [1, 14]
          [parameter_declaration](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 14] - [1, 15]
            type: [type_identifier](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 14] - [1, 15]
          [)](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [1, 15] - [1, 16]
        [identifier](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [2, 4] - [2, 7]
        [ERROR](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [2, 7] - [2, 8]
          [*](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [2, 7] - [2, 8]
        [identifier](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [2, 9] - [2, 10]
    [;](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [2, 10] - [2, 11]
  [compound_statement](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [3, 4] - [4, 5]
    [{](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [3, 4] - [3, 5]
    [}](https://tree-sitter.github.io/tree-sitter/7-playground.html#) [4, 4] - [4, 5]

Repro

[v-p-b]

I think pointer return types in function declarations is problematic in itself. Sample code:

int* foo(int a){

}

AST:

translation_unit [0, 0] - [3, 0]
  function_definition [0, 0] - [2, 1]
    type: primitive_type [0, 0] - [0, 3]
    declarator: pointer_declarator [0, 3] - [0, 15]
      declarator: function_declarator [0, 5] - [0, 15]
        declarator: identifier [0, 5] - [0, 8]
        parameters: parameter_list [0, 8] - [0, 15]
          parameter_declaration [0, 9] - [0, 14]
            type: primitive_type [0, 9] - [0, 12]
            declarator: identifier [0, 13] - [0, 14]
    body: compound_statement [0, 15] - [2, 1]

As you can see function_declarator is parsed as a child of a pointer_declarator, while in case of non-pointer return types the return type and the declarator nodes are siblings. Adding more indirections also pushes the declaration deeper in the tree too:

int** foo(int a){

}

translation_unit [0, 0] - [3, 0]
  function_definition [0, 0] - [2, 1]
    type: primitive_type [0, 0] - [0, 3]
    declarator: pointer_declarator [0, 3] - [0, 16]
      declarator: pointer_declarator [0, 4] - [0, 16]
        declarator: function_declarator [0, 6] - [0, 16]
          declarator: identifier [0, 6] - [0, 9]
          parameters: parameter_list [0, 9] - [0, 16]
            parameter_declaration [0, 10] - [0, 15]
              type: primitive_type [0, 10] - [0, 13]
              declarator: identifier [0, 14] - [0, 15]
    body: compound_statement [0, 16] - [2, 1]