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bug: Parse error with function annotations #310

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Description

@alexle0nte

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-cpp

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

tree-sitter 0.25.3 (2a835ee029dca1c325e6f1c01dbce40396f6123e)

Describe the bug

When parsing code that uses function annotations, the parse tree incorrectly reports an ERROR node.
For example, given the following snippet that contains a function annotated with EXPORT:

#define EXPORT __attribute__((visibility("default")))

EXPORT
void foo() {}

The following error appears in the parse tree: (ERROR [3, 0] - [3, 4].

Steps To Reproduce/Bad Parse Tree

  1. Write the code above in a C++ file.
  2. Run tree-sitter parse on the file.
  3. Observe the obtained parse tree:
(translation_unit [0, 0] - [4, 0]
  (preproc_def [0, 0] - [1, 0]
    name: (identifier [0, 8] - [0, 14])
    value: (preproc_arg [0, 15] - [0, 53]))
  (function_definition [2, 0] - [3, 13]
    type: (type_identifier [2, 0] - [2, 6])
    (ERROR [3, 0] - [3, 4]
      (identifier [3, 0] - [3, 4]))
    declarator: (function_declarator [3, 5] - [3, 10]
      declarator: (identifier [3, 5] - [3, 8])
      parameters: (parameter_list [3, 8] - [3, 10]))
    body: (compound_statement [3, 11] - [3, 13])))

Expected Behavior/Parse Tree

The parse tree should not have errors.

Repro

#define EXPORT __attribute__((visibility("default")))

EXPORT
void foo() {}

Activity

  1. eezstreet commented on Jun 2, 2025

    @eezstreet
    Contributor

    I would think that this is not an issue with the tree-sitter grammar, because the grammar only describes a well-formed piece of source code. Because there is preprocessing required to yield well-formed source code here, there is no issue.

    The correct course of action would be to take this code:

    #define EXPORT __attribute__((visibility("default")))
    
    EXPORT
    void foo() {}

    And do a substitution of the preprocessor macro:

    #define EXPORT __attribute__((visibility("default")))
    
    __attribute__((visibility("default")))
    void foo() {}

    If that yields an error, then there is a problem. At least in my humble opinion anyway. :)

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